WO2015051259A1

WO2015051259A1 - Pharmaceutical compositions and methods of use

Info

Publication number: WO2015051259A1
Application number: PCT/US2014/059066
Authority: WO
Inventors: Aravind MITTUR; Liang Dong; Suneel Gupta; Yogesh Patil
Original assignee: Impax Laboratories, Inc.
Priority date: 2013-10-04
Filing date: 2014-10-03
Publication date: 2015-04-09

Abstract

Disclosed are compositions and methods for administering an NMDA receptor antagonist to a patient. The compositions may be administered orally, buccally, sublingually or rectally.

Description

PHARMACEUTICAL COMPOSITIONS AND METHODS OF USE

This application claims the benefits of United States Provisional Patent Application No. 61/887, 173 filed on October 4, 2013.

Field of the Invention

The present invention relates to compositions and methods for administering an NMDA receptor antagonist to a patient in need of NMDA receptor antagonist therapy and preferably to a patient suffering from depression. Embodiments of the present invention include solid, liquid, and semi-solid compositions that enable oral, buccal, sublingual, or rectal delivery of an NMDA receptor antagonist to a patient and preferably in an abuse resistant or deterrent composition.

Background

NMDA receptor antagonists are a class of compounds that inhibit N-Methyl-D-

Aspartate receptors (NMDAR). Examples of NMDA receptor antagonists include ketamine, dextromethorphan, phencyclidine, memantine, riluzole, amantadine, nitrous oxide and synthetic opioids such as meperidine, methadone, dextropropoxyphene, tramadol and ketobemidone. NMDA receptor antagonists have been used as anesthetics and for pain management in humans and animals. U.S. Patent Application Publication Nos.

2007/0287753 Al and 2012/0225949 Al describe the potential use of ketamine, an NMDAR receptor antagonist, for the treatment of depression. Some of the NMDA receptor antagonists have been reported to provide hallucinogenic or euphoric properties, and therefore they have the potential for abuse, especially by recreational drug users.

Drug abuse of prescription medications is a widespread and prevalent problem in almost all societies. Sometimes the abuse can be as simple as the diversion of appropriately prescribed medications to an individual that does not have a medical need for the medication but is merely seeking to obtain a "high." Other times, the abuse may involve the adulteration of medications to obtain a greater concentration of the drug or a quicker release of the drug. When a medication is adulterated, the drug abuser typically consumes the drug via parenteral administration, i.e., injection, or by nasal administration, i.e., inhalation or snorting. To combat parenteral or nasal administration by a drug abuser a number of different abuse prevention or deterrent methods have been proposed. For example, crush resistant opioid tablets have been described in U.S. Patent No. 8, 114,383 and U.S. Patent Application Publication No. 2009/0081290. Another abuse deterrent method is the addition of aversive agents such as mucosal irritants, bittering agents and/or emetics to opioid compositions as described in U.S. Patent Nos. 7, 141,250 and 7,510,726 and U.S. Patent Application

Publication No. 2009/0011016 Al. It has also been proposed that medication abuse can be deterred by adding gelling agents to potentially abusable medications thereby making it difficult to draw the adulterated medication with the gelling agent through the needle of a syringe such as described in U.S. Patent No. 7,776,314. The addition of an opioid antagonist such as naltrexone or naloxone to an opioid composition has also been described in U.S. Patent Nos. 4, 935,428; 7,682,634; 7,815,934 and 8,454,996 as a method of deterrence.

Summary of the Invention

It is an objective of the present invention to provide a solid, liquid, or semi-solid composition that enables the oral, buccal, sublingual, or rectal delivery of an NMDA receptor antagonist to a patient.

It is a further objective of the present invention to provide an abuse deterrent composition for the oral, buccal, sublingual, or rectal delivery of a NMDA receptor antagonist to a patient.

It is still a further objective of the present invention to provide a method for administering an NMDA receptor antagonist to a patient for treating afflictions such as depression, bipolar disorder, acute suicidal ideation and thoughts, restless leg syndrome or pain wherein the NMDA receptor antagonist is administered orally, buccally, sublingually, or rectally and preferably in the form of an abuse deterrent composition.

The above objectives and others are obtained by the present invention which comprises an abuse deterrent composition comprising a therapeutic amount of an NMDA receptor antagonist. Embodiments of the present invention may comprise one or more of the following abuse deterrent features:

i) the composition comprises a material that swells and/or gels when the

composition is placed in an aqueous environment;

ii) the composition comprises one or more aversive agent such as a mucosal irritant, bittering agent or emetic agent;

iii) the composition comprises a self-emulsifying component wherein the NMDA receptor antagonist is incorporated into, i.e., admixed, dissolved, or suspended in the self-emulsifying component; the composition comprises a polymer that is soluble in common household solvents such as water, ethanol, isopropyl alcohol, acetone, mineral oil and combinations thereof to prevent, inhibit or hinder the extraction or purification of the NMDA receptor antagonist from the composition into common household solvent.

Detailed Description

Before the present invention is further described, it is to be understood that this invention is not limited to the particular embodiments described, as such may, of course, vary. It also is to be understood that the terminology used herein is for the purpose of describing particular embodiments only, and is not intended to be limiting, since the scope of the present invention will be limited only by the appended claims.

It must be noted that as used herein and in the appended claims, the singular forms "a," "an," and "the" include plural referents unless the context clearly dictates otherwise. It is further noted that the claims may be drafted to exclude any optional element.

The terms "individual," "subject," or "patient" are used interchangeably. As used herein, they mean any mammal. In some embodiments, the mammal is a human. In some embodiments, the mammal is a non-human.

The terms "treat," "treating" or "treatment," and other grammatical equivalents as used herein, include alleviating, inhibiting or reducing symptoms, reducing or inhibiting severity of, reducing incidence of, prophylactic treatment of, reducing or inhibiting recurrence of, preventing, delaying onset of, delaying recurrence of, abating or ameliorating a disease or condition symptoms, ameliorating the underlying metabolic causes of symptoms, inhibiting the disease or condition, e.g., arresting the development of the disease or condition, relieving the disease or condition, causing regression of the disease or condition, relieving a condition caused by the disease or condition, or stopping the symptoms of the disease or condition. The terms further include achieving a therapeutic benefit. By therapeutic benefit is meant eradication or amelioration of the underlying disorder being treated, and/or the eradication or amelioration of one or more of the physiological symptoms associated with the underlying disorder such that an improvement is observed in the individual.

The terms "effective amount" or "therapeutically effective amount" as used herein, refer to a sufficient amount of at least one agent being administered which achieves a desired result, e.g., to relieve to some extent one or more symptoms of a disease or condition being treated. In certain instances, the result is a reduction and/or alleviation of the signs, symptoms, or causes of a disease, or any other desired alteration of a biological system. In some embodiments, the effective amount is a dose that is generally effective in alleviating, reducing, noticeably reducing, or eliminating, symptoms associated with depression, bipolar disorder or mania. In certain instances, an "effective amount" for therapeutic uses is the amount of the composition comprising an agent as set forth herein required to provide a clinically significant decrease in a disease. An appropriate "effective" amount in any individual case is determined using any suitable technique, such as a dose escalation study.

The terms "administer," "administering," "administration," and the like, as used herein, refer to the methods that are used to enable delivery of agents or compositions to the desired site of biological action. These methods include, but are not limited to oral, buccal sublingual, rectal and topical administration. Administration techniques that are optionally employed with the agents and methods described herein, include, e.g., as discussed in Goodman and Gilman, The Pharmacological Basis of Therapeutics, 9^th ed. , 1996 and Remington's, Pharmaceutical Sciences 21^st ed. 2005.

The term "pharmaceutically acceptable" as used herein, refers to a material that does not abrogate the biological activity or properties of the agents described herein, and is relatively nontoxic (i.e., the toxicity of the material is significantly outweighed by the benefit of the material). In some instances, a pharmaceutically acceptable material is administered to an individual without causing significant undesirable biological effects or significantly interacting in a deleterious manner with any of the components of the composition in which it is contained.

The term "depression" as used herein refers a clinical mood disorder in which episodes of depression range in severity from mild to severe with symptoms including lowering of mood, decrease in activity, fatigue, disturbed sleep, diminished self-esteem, suicidal thoughts, and ideas of guilt and worthlessness. These symptoms interfere with a patient's ability to work, sleep, study, eat, or enjoy life. An episode can occur only once in a person's lifetime, but more often, a person has several episodes. Major depressive disorder ("MDD") is a subcategory of depression typically characterized by one or more of the aforementioned symptoms for a period of 14 days or more.

As used herein the term "bipolar disorder" is a disorder characterized by unusually intense emotional states that occur in distinct periods called "mood episodes." An overly elated or overexcited state is called a manic episode, and an extremely sad or hopeless state is called a depressive episode. Individuals who experience manic episodes also commonly experience depressive episodes or symptoms, or mixed episodes in which features of both mania and depression are present at the same time. These episodes are usually separated by periods of "normal" mood, but in some individuals, depression and mania may rapidly alternate, known as rapid cycling. Extreme manic episodes can sometimes lead to psychotic symptoms such as delusions and hallucinations. Patients affected by bipolar disorder have had at least one manic or hypomanic (mild mania) episode. Patients with full manias and depression are indicated as having "bipolar I disorder." Patients with hypomania and depression are described as having "bipolar II disorder." Onset of episodes tends to be acute, with symptoms developing over days to weeks.

Symptoms of bipolar disorder may also include mood cycling (i.e., cycling between manic episodes, depressive episodes, and normal moods), obsessive fear of harm, severe aggression, territorial aggression, thermal dysregulation, night sweats, early and middle insomnia, arousal disorders of sleep (nightmares, night-terrors, teeth grinding, bedwetting), rapid speech, germ contamination fears, hoarding, extreme separation anxiety, hallucinations, delusions, and sweet cravings.

Where a range of values is provided, it is understood that each intervening value, to the tenth of the unit of the lower limit unless the context clearly dictates otherwise, between the upper and lower limit of that range and any other stated or intervening value in that stated range, is encompassed within the invention. The upper and lower limits of these smaller ranges may independently be included in the smaller ranges, and are also encompassed within the invention, subject to any specifically excluded limit in the stated range. Where the stated range includes one or both of the limits, ranges excluding either or both of those included limits are also included in the invention.

The publications discussed herein are provided solely for their disclosure prior to the filing date of the present application. Nothing herein is to be construed as an admission that the present invention is not entitled to antedate such publication by virtue of prior invention. Further, the dates of publication provided may be different from the actual publication dates which may need to be independently confirmed.

Unless defined otherwise, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention belongs. Although any methods and materials similar or equivalent to those described herein can also be used in the practice or testing of the present invention, the preferred methods and materials are now described. All publications mentioned herein are incorporated herein by reference to disclose and describe the methods and/or materials in connection with which the publications are cited. As discussed previously, the present invention is a composition comprising an NMDA receptor antagonist, for oral, buccal, sublingual, or rectal delivery.

The NMDA receptor antagonist can be ketamine, dextromethorphan, phencyclidine, nitrous oxide or a synthetic opioid such as meperidine, ibogaine, methadone,

dextropropoxyphene, tramadol and ketobemidone and pharmaceutically acceptable salts and isomers thereof. In one embodiment of the present invention the NMDA receptor antagonist is ketamine. As used herein, the term "ketamine" refers to ketamine (i.e., [(2-2- chlorophenyl)-2-(methylamino)-cyclohexanone]), metabolites of ketamine (e.g., norketamine) and pharmaceutically acceptable salts thereof (e.g., ketamine hydrochloride, ketamine hydrobromide, ketamine sulfate, ketamine mesylate, ketamine phosphate, ketamine succinate, ketamine tannate, and ketamine maleate). Also included within the scope of the term "ketamine," are isomers and enantiomers of ketamine and its metabolites such as desmethyl ketamine, also known as norketamine, dehydronorketamine, hydroxynorketamine and hydroxyketamine and the metabolites of the enantiomers themselves as well as deuterated analogs. A more complete description of possible metabolites can be found in

Zarate et al, "Relationship of Ketamine's Plasma Metabolites with Response, Diagnosis, and Side Effects in Major Depression," Biol Psychiatry, 2012; 72: 331-338 and Turfus et al., "Use of Human Microsomes and Deuterated Substrates: An Alternative Approach for the Identification of Novel Metabolites of Ketamine by Mass Spectrometry," Drug Metabolism and Disposition, 2009; 37: 1769-1778 which are incorporated herein by reference. Ketamine is a chiral compound. The R and S stereoisomers have different binding affinities. S- ketamine, sometimes referred to as esketamine has about four times greater affinity for the PCP site of the NMDA receptor than does R-ketamine. S-ketamine hydrochloride which is employed in certain embodiments of the present invention, has the following structure:

The synthesis of ketamine is described in U.S. Patent No. 3,254, 124 and the isolation of its isomers is described in Great Britain Patent 1 330 878 both of which are incorporated herein by reference.

The compositions of the present invention will contain and deliver a therapeutically effective amount of NMDA receptor antagonist. The therapeutic effective amount will vary depending upon the specific NMDA receptor antagonist, body weight of the patient, disease condition being treated, indicated use and delivery mechanism of the composition. The determination of the therapeutically effective amount of NMD A receptor antagonist can be determined by a person of ordinary skill in the art based upon known and reported pharmacokinetic values for the NMDA receptor antagonist such as those reported in

Goodman and Gilman, The Pharmacological Basis of Therapeutics, 9^th ed. , 1996 which is incorporated herein by reference. Typically, the therapeutically effective amount of NDMA receptor antagonist ranges from about 0.001 mg/kg/day to about 5 mg/kg/day, preferably about 0.01 mg/kg/day to about 4 mg/kg/day and most preferably about 0.1 mg/kg/day to about 3 mg/kg/day.

With respect to ketamine, the therapeutically effective amount will also vary with the condition being treated. For example, a dose between 0.5mg/kg to 5 mg/kg has been administered intravenously or 5 mg/kg to 15 mg/kg has been administered intramuscularly to induce surgical anesthesia. It has also been reported in U.S. Patent No. 6,855,735 which is incorporated herein by reference, that 2 mg to 100 mg per day of ketamine administered orally is useful in treating restless leg syndrome. U.S. Patent Application Publication Nos. 2012/0225949 Al and 2007/0287753 Al, both of which are incorporated herein by reference, teach the administration of 0.5 mg to about 250 mg per day administered intravenously, intranasally, or transdermally for treating depression and bipolar disorders.

Some embodiments of the present inventions will contain about 1 mg to about 350 mg, preferably about 2.5 mg to 250 mg and most preferably about 10 mg to about 200 mg of NDMA receptor antagonist, preferably ketamine of a pharmaceutically acceptable salt thereof, and most preferably S-ketamine or a pharmaceutically acceptable salt thereof. In a further sublingual or buccal embodiment of the present invention the dosage form will comprise S-ketamine or a pharmaceutically acceptable salt thereof in an amount of about 10 mg to about 200 mg based upon the free base equivalent, preferably about 15 mg to about 175 mg based upon the free base equivalent and most preferably about 20 mg to about 150 mg based upon the free base equivalent.

The NDMA receptor antagonist, preferably ketamine or a pharmaceutically acceptable salt thereof and most preferably S-ketamine or a pharmaceutically acceptable salt thereof, employed in the compositions of the present invention may be micronized, and exhibit a mean particle size (D50) of less than or equal to 100 microns, preferably less than or equal to 50 microns and most preferably less than or equal to 10 microns.

Embodiments of the present invention will include compositions that are designed for oral, buccal, sublingual, or rectal delivery and may be in a solid, liquid or semi-solid state. The compositions will comprise the NMDA receptor antagonist and at least one

pharmaceutically acceptable excipient, preferably one or more of the following abuse deterrent features:

i) the composition comprises a material that swells and/or gels when the

composition is placed in an aqueous environment;

ii) the composition comprises one or more aversive agents such as a mucosal irritant, bittering agent or emetic agent;

iii) the composition comprises a self-emulsifying component wherein the NMDA receptor antagonist is incorporated into, i.e., admixed, dissolved, or suspended in the self-emulsifying component;

iv) the composition comprises a polymer that is soluble in common household solvents such as water, ethanol, isopropyl alcohol, acetone mineral oil and combinations thereof to prevent, inhibit or hinder the extraction or purification of the NMDA receptor antagonist from the composition into the common household solvent.

Materials that gel when placed in an aqueous environment are natural and synthetic materials, preferably polymers, that upon contact with water, absorb the water and swell, at least 10%, 20%, 50% or more compared to their original dry volume, thereby forming a viscous or semi-viscous substance that significantly reduces and/or inhibits the ability of the drug abuser to extract of the drug from the dosage form because the drug is entrapped in the gelled material. Once the material that gels absorbs water and swells the viscous or semi- viscous substance containing the NMDA receptor antagonist is also difficult to draw into the needle of a syringe, such as a needle with an internal lumen diameter of about 1.37 mm (a 15 gauge) or smaller, preferably an internal lumen of about 1.194 mm (16 gauge) or smaller and to inject the viscous or semi-viscous substance. Examples of materials that gel when placed in an aqueous environment include but are not limited to pharmaceutically acceptable polymers such as polyethylene oxide, polyvinyl alcohol, hydroxypropyl methylcellulose, hydroxypropyl cellulose and carbomers.

The polyethylene oxide can have an average molecular weight ranging from about 300,000 to about 9,000,000, more preferably from about 600,000 to about 7,000,000, and most preferably at least about 900,000 to about 5,000,000. In one embodiment, the polyethylene oxide includes a high molecular weight polyethylene oxide. In one embodiment, the average particle size of the polyethylene oxide ranges from about 840 to about 2,000 microns. In another embodiment, the density of the polyethylene oxide can range from about 1.15 to about 1.26 g/ml. In another embodiment, the viscosity can range from about 8,800 to about 17,600 cps. Preferably, the polyethylene oxide is a commercially available and pharmaceutically acceptable homopolymer having moisture content of no greater than about 1% by weight. Examples of suitable, commercially available polyethylene oxide polymers include POLYOX^® WSR N-l 105, WSR 301, WSR 303 and/or WSR Coagulant, available from Dow Chemicals.

The polyvinyl alcohol can have a molecular weight ranging from about 20,000 to about 200,000. The specific gravity of the polyvinyl alcohol can range from about 1.19 to about 1.31 and the viscosity from about 4 to about 65 cps. Examples of suitable, commercially available polyvinyl alcohol polymers include PVA, USP, available from Spectrum Chemical Manufacturing Corporation, New Brunswick, NJ 08901.

The hydroxypropyl methylcellulose can have a number average molecular weight ranging from about 40,000 to about 1,500,000. The specific gravity of the hydroxypropyl methyl cellulose can range from about 1.19 to about 1.31, with an average specific gravity of about 1.26 and a viscosity of a 2% aqueous solution at 20°C of about 100 to 200,000 cps, preferably about 1,000 to about 100,000. The hydroxypropyl methylcellulose used in the formulation can be a water-soluble synthetic polymer. Examples of suitable, commercially available hydroxypropyl methylcellulose polymers include Methocel K100 LV, Methocel K4M, Methocel K15M and Methocel K100M available from Dow Chemicals.

The hydroxypropyl cellulose can have a molecular weight ranging from about

350,000 to about 2,000,000, and typically from about 750,000 to about 1,500,000. The specific gravity of the hydroxypropyl cellulose can range from about 1.19 to about 1.31, with an average specific gravity of about 1.2224 and a viscosity of a 2% aqueous solution at 20°C of about 100 to 20,000 cps, preferably about 150 to about 10,000. The hydroxypropyl cellulose used in the formulation can be a water-soluble synthetic polymer. Examples of suitable, commercially available hydroxypropyl methylcellulose polymers include KLUCEL GF, KLUCEL MF and KLUCEL HF.

The carbomers can have a molecular weight ranging from 700,000 to about

4,000,000. The viscosity of the polymer can range from about 4,000 to about 39,400 cps. Examples of suitable, commercially available carbomers include carbopol 934P NF, carbopol 974P NF and carbopol 97 IP NF, available from Noveon Pharmaceuticals.

Additional materials that gel when placed in an aqueous environment that may be used in the present invention, include carboxymethylcellulose calcium,

carboxymethylcellulose sodium, guar gum, locust bean gum, xanthan gum, hydroxyethyl cellulose, hydroxypropyl cellulose, methyl cellulose, acrylic polymers and copolymers, sodium alginate, croscarmellose sodium, sodium starch glycolate, crospovidone and mixtures thereof. Many of the aforementioned materials that gel are available in different grades. It is preferred that the grade selected for incorporation into the abuse deterrent compositions of the present invention exhibit a viscosity of at least 500 cps, preferably at least 1000 cps when a 2% w/w of the material is added to water at 20°C.

The material that gels when placed in the aqueous environment should be able to prevent less than or equal to about 95%, 90%, 85%, 80%, 75%, 70%, 65%, 60%, 55%, 50%, 45%, 40%, 35%, 30%, 25%, 20%, 15% or 10% of the total amount of drug in a dosage form from being recovered from a solvent in contact with a dosage form of the present invention according to the test procedures outlined in U.S. Patent No. 7,510,726.

The material that gels should be comprise about 1% to about 60%, preferably about 2% to about 50% and most preferably about 5% to about 40% of the abuse deterrent composition, based on the total weight of the abuse deterrent composition. When a material that gels is employed in the abuse deterrent composition of the present invention, the abuse deterrent composition should be free or substantially free of water that is available to hydrate the gelling material, i.e., less than 2% of free or unbound water. If the abuse deterrent composition of the present invention is a liquid and contains a material that gels when placed in an aqueous environment, the composition should employ non-aqueous solvents such as dehydrated ethanol, low molecular weight polyethylene glycols, glycerin and oils which are discussed below.

As described above, the present invention can include one or more aversive agents such as mucosal irritants, bittering agents, emetic agents or combinations thereof.

The mucosal irritants are pharmaceutically acceptable excipients that irritate the mucosal membrane and the nasal tissues in particular if the abuse deterrent composition of the present invention is crushed and inhaled or snorted. Such compounds include, but are not limited to surfactants. In one embodiment, suitable surfactants include sodium lauryl sulfate, poloxamer, sorbitan monoesters and glyceryl monooleates. Other suitable mucosal irritants include capsaicin, a capsaicin analog with similar type properties as capsaicin, and the like. Some capsaicin analogues or derivatives include for example and without limitation, resiniferatoxin, tinyatoxin, heptanoylisobutylamide, heptanoyl guaiacylamide, other isobutylamides or guaiacyl amides, dihydrocapsaicin, homovanillyl octylester, nonanoyl vanillylamide, or other compounds of the class known as vanilloids. A more complete list of irritants is included in U.S. Patent Application Publication No. 2007/0020188 Al which is incorporated herein by reference.

One or more of the mucosal irritants can be present in amount of from about 0% to about 30%, preferably about 2% to about 25% and most preferably about 5% to about 20% by weight based upon the total weight of the composition.

The bittering agents employed in the present invention are pharmaceutical excipients that produce a bitter taste upon inhalation or oral administration of an adulterated dosage form which spoils or hinders the pleasure of obtaining a high from the adulterated dosage form, and preferably deters the abuse of the dosage form. Examples of bittering agents that may be employed including, without limitation, natural, artificial and synthetic flavor oils and flavoring aromatics and/or oils, oleoresins and extracts derived from plants, leaves, flowers, fruits, and so forth, and combinations thereof. Non-limiting representative flavor oils include spearmint oil, peppermint oil, eucalyptus oil, oil of nutmeg, allspice, mace, oil of bitter almonds, menthol and the like. Useful bittering agents can be artificial, natural and synthetic fruit flavors such as citrus oils including lemon, orange, lime, grapefruit, and fruit essences and so forth. Additional bittering agents include sucrose derivatives (e.g., sucrose octaacetate), chlorosucrose derivatives, quinine sulphate, and the like. A more complete list and description of bittering agents can be found in U.S. Patent Application Publication No. 2007/0020188 which is incorporated herein by reference.

One or more of the bittering agents can be present in an amount of from about 0% to about 30%, preferably about 2% to about 25% and most preferably about 5% to about 20% by weight based upon the total weight of the composition. The bittering agent should be employed in an amount that imparts a bitter or unpleasant taste if the composition comprising the NMDA receptor antagonist is adulterated. It is also understood that some of these bittering agents may be used at levels and in manners that mask the unpleasant taste when the composition comprising the NMDA receptor antagonist is not adulterated.

The emetic agents employed in the present invention are pharmaceutical excipients that are sequestered (not available for biological absorption) or present in amounts below a level that would induce emesis. However, when the composition is abused by crushing, grinding, dissolving or ingested beyond the prescribed dose or amount the emetic agent is released at levels that induce emesis. Examples of emetics include zinc sulfate, cephaeline, methyl cephaeline, psychotrine, O-methylpsychotrine, ammonium chloride, potassium chloride, magnesium sulfate, ferrous gluconate, ferrous sulfate, aloin, and emetine. A more detailed description of emetic agents and their use can be found in U.S. Patent No. 7,510,726 and U.S. Patent Application Publication No. 2007/0020188 Al which are incorporated herein by reference.

Compositions of the present invention may include one or more of the above described aversive agents. The total amount of aversive agent may range from about 0.5% to about 50%, preferably about 1% to about 35% and most preferably about 2% to about 20% based upon the total weight of the composition.

As discussed above, embodiments of the present invention may comprise a self- emulsifying component wherein the NMDA receptor antagonist is incorporated into, i.e., admixed, dissolved, or suspended in the self-emulsifying component. In certain embodiment the self-emulsifying component is part of or is a self-emulsifying drug delivery system

(SEDDS) or a self-microemulsifying drug delivery system (SMEDDS) wherein the NMDA receptor antagonist is incorporated into the SEDDS or SMEDDS. The SEDDS and

SMEDDS are known in the art and generally described in Shah et al., "Self-Emulsifying Drug Delivery Systems (SEDDS) With Poylglycolyzed Glycerides for Improving In Vitro Dissolution and Oral Absorption of Lipophilic Drugs", International Journal of

Pharmaceuticals, 106 (1994) pp. 15-23; Constantinides, "Lipid Microemulsions for

Improving Drug Dissolution and Oral Absorption: Physical and Biopharmaceutical Aspects", Pharmaceutical Research, Vol. 12. No. 11, 1995, pp. 1561-1572 and U.S. Patent Nos. 8,367, 102 and 7,435,427 which are incorporated herein by reference. In general, the self-emulsifying component, and the SEDDS and SMEDDS in particular, are a composition comprising the NMDA receptor antagonist and a lipophilic excipient that when administered to a patient will self-emulsify in the presence of biological fluids such as saliva, gastric fluid or intestinal fluid creating small discrete units comprising the NMDA receptor antagonist and the lipophilic excipient. SEDDS produce opaque or cloudy dispersions with droplet sizes ranging from 200 nm to 5 μιη. SMEDDS result in clear or translucent microemulsions with particle sizes < 200 nm. In certain embodiments, the average particle sizes of SMEDDS or SEDDS are 50, 75, 100, 125, 150, 175, 200, 225, 250, 275, 300, 325, 350, 375, 400, 425, 450, 500, 600, 700, 800, 900, or 1000 nm; or 1.5, 2, 2.5, 3, 3.5, 4, 4.5, or 5 μιη.

The lipophilic excipient should be a liquid at temperatures of 37°C or less, and preferably at room temperature. The lipophilic excipient should exhibit a

hydrophilic/lipophilic balance (HLB) value of 7 or less, preferably of 6 or less and more preferably of 5 or less. The lipophilic excipient may be a fatty acid, a medium chain triglyceride, a fatty acid ester, a vegetable oil such as peanut oil, corn oil, soy bean oil, olive oil, hydrogenate vegetable oil or mixtures thereof as well as liquid non-ionic surfactants which have an HLB value below 7. In certain sublingual embodiments the lipophilic excipient should comprise about 25 % (w/w) of the composition to about 75 % (w/w), preferably about 30% (w/w) to about 70% (w/w) and most preferably about 35% (w/w) to about 65% (w/w) of the composition.

In certain embodiment the lipophilic excipient is a polyglycolyzed glyceride such as oleoyl polyoxyglycerides commercially available under the trade name LABRAFIL

M1944CS; linoleoyl polyoxyglycerides commercially available under the trade name LABRAFIL M2125CS; an acetylated monoglyceride commercially available under the trade name MYVACET 9-45K; liquid lecithin commercially available under the trade name CENTROPHASE; diesters of propylene glycol obtained from coconut oil commercially available under the trade name CAPTEX 200; triglycerides obtained from coconut oil commercially available under the trade name CAPTEX 355 or MIGLYOL 812; monoolein: propylene glycol (90: 10) commercially available under the trade name ARLACEL 186 or mixtures thereof.

In addition to the NMDA receptor antagonist and lipophilic excipient the self- emulsifying component, and the SEDDS and SMEDDS in particular, may further comprise a surfactant, a water-miscible non-aqueous solvent and combinations thereof.

A surfactant refers to a compound that reduces the surface tension of liquids, or reduces interfacial tension between two liquids or a liquid and a solid, the surface tension being the force acting on the surface of a liquid, tending to minimize the energy of the surface. Surfactants have sometimes been used in pharmaceutical formulations, including delivery of drugs, in order to modify the absorption of the drug or its delivery to the target tissues. A non-ionic surfactant refers to a surfactant which lacks net ionic charge. In certain embodiments, the non-ionic surfactant is water-soluble.

A critical micelle concentration (CMC) is defined as the concentration of surfactants above which micelles form and almost all additional surfactants added to the system go to form micelles. Embodiments of the present invention provide a composition comprising a non-ionic surfactant at any level, however, specific embodiments of the present invention comprise about 0 to about 40 weight percent of a non-ionic surfactant, preferably about 1 to about 30 weight percent of a non-ionic surfactant and most preferably about 2 to about 20 weight percent of a non-ionic surfactant based upon the total weight of the composition. The foregoing weight percent may be based upon a single non-ionic surfactant or mixtures of one or more non-ionic surfactants. Although any type of non-ionic surfactants may be used in embodiments of the present invention, certain embodiments of the present invention employ non-ionic surfactants that exhibit an HLB value of 10 or less, preferably 8 or less and most preferably 6 or less.

The non-ionic surfactant may be selected from the group consisting of a

polyethoxylated castor oil, a polyoxyethylene alkyl ester, a polyglycolyzed glyceride, a sorbitan fatty acid ester, a glycerin fatty acid ester, a fatty acid polyglyceride, a fatty acid alcohol polyglycol ether, acetylene glycol, acetylene alcohol, an oxyalkylene block polymer, a polyoxyethylene alkyl ether, a polyoxyethylene alkylaryl ether, a polyoxyethylene styrylaryl ether, a polyoxyethylene glycol alkyl ether, a polyoxyethylene fatty acid ester, a polyoxyethylene sorbitan fatty acid ester, a polyoxyethylene glycerin fatty acid ester, a polyoxyethylene hydrogenated castor oil, a polyoxypropylene fatty acid ester or a mixture of the foregoing. A further listing of possible non-ionic surfactants can be found on pages 1243- 1249 of Martindale, The Extra Pharmacopoeia 29^th ed. which is incorporated herein by reference.

In certain embodiments the non-ionic surfactants may comprise fatty alcohol acid or amide ethoxylates, monoglyceride ethoxylates, sorbitan ester ethoxylates alkyl

polyglycosides, mixtures thereof, and the like. Certain non-ionic surfactants include polyoxyethylene derivatives of polyol esters, such as Polysorbate 20 (TWEEN 20®), Polysorbate 40 (TWEEN 40®) Polysorbate 60 (TWEEN 60®), and Polysorbate 80 (TWEEN 80®).

In certain embodiments the non-ionic surfactant may also comprise d-alpha tocopheryl polyethylene glycol 1000 succinate (TPGS), nonoxinols, poloxamers, sorbitan monolaurate, sorbitan monooleate, sorbitan monopalmitate, sorbitan monostearate, sorbitan sesquioleate, sorbitan trioleate, tyloxapol and mixtures of the foregoing.

In certain embodiments, the non-ionic surfactant should be a liquid at room temperature. Alternatively the non-ionic surfactant should exhibit a melting point of 35°C or lower, preferably 30°C or lower. The non-ionic surfactant should also be soluble in the water miscible solvent and/or lipophilic excipient employed in the liquid or semi-solid composition embodiments of the present invention.

The compositions of the present invention may optionally comprise one or more ionic surfactants. An ionic surfactant refers to a surfactant which has net ionic charge. In certain embodiments, the ionic surfactant is water-soluble. If present the ionic surfactant may comprise between 0 and about 10 weight percent of the composition, preferably between 0 and about 5 weight percent of the composition and most preferably between 0 and about 2.5 weight percent of the composition.

Any of a variety of ionic surfactants is suitable for use in the compositions. Suitable ionic surfactants include, but are not limited to, carboxylates such as soaps, acyl lactylates, acyl amides of amino acids, esters of sulfuric acid such as alkyl sulfates and ethoxylated alkyl sulfates, sulfonates such as alkyl benzene sulfonates, acyl isethionates, acyl taurates and sulfosuccinates, phosphates, quaternary ammonium salts and ethoxylated amines. An example of a preferred ionic surfactant is sodium lauryl sulfate.

Any of a variety of water-miscible non-aqueous solvents is suitable for use in the compositions of the present invention and the liquid or semi-solid compositions in particular. Some examples of the water-miscible solvents are propylene glycol, polyethylene glycol, alcohol, diethylene glycol monoethyl ether, 2-(2-ethoxyethoxy)ethanol, triacetin or mixtures of the foregoing. Depending upon the type of liquid formulation, the amount of water- miscible solvent will vary.

Certain embodiments of the present invention may comprise alcohol as a water- miscible solvent. Alcohol, also known as ethanol or ethyl alcohol, may be used as the dehydrated alcohol, which according to the USP contains not less than 99.2% by weight of ethanol or as regular alcohol which according to the USP contains not less than 92.3% and not more than 93.8% by weight of ethanol. In certain embodiments where USP alcohol with 92.3% -93.8% ethanol is employed in the abuse deterrent compositions of the present invention and a material that gels when placed in an aqueous environment is also employed in the abuse deterrent composition, the total amount of USP alcohol in the composition should be an amount that contributes 2% or less, preferably 1% or less of water to the total weight of the composition.

As described above, the abuse deterrent compositions of the present invention may further include a polymer that is soluble in common household solvents and which a drug abuser may use to extract a drug from a dosage form. Some of the common house hold solvents are water, ethanol, isopropyl alcohol, acetone and mineral oil. It has been reported that drug abusers seek to extract abusable drugs from dosage forms by mixing the dosage forms with the common household solvents such as acetone. This mixture in theory will dissolve the drug but not unwanted excipients and lead to a concentrated drug extraction that when injected or inhaled, after the common household solvent has been removed will lead to a desired high or euphoric state. By including a polymer that is soluble in the common household solvent in the abuse deterrent composition, when a drug abuser seeks to extract the drug with the common household solvent such as acetone, the polymer will also be extracted along with the self-emulsifying component if present. Once the common household solvent is removed, the extracted polymer, drug and self-emulsifying component if present, will produce a mass that is difficult to inject or inhale. Polymers that are soluble in common household solvents such as water, ethanol, isopropyl alcohol, acetone mineral oil and combinations thereof and that may be included in the abuse deterrent compositions of the present invention include but are not limited to hydroxypropyl methylcellulose,

ethylcellulose, povidone, copovidone, polymethacrylates and mixtures thereof.

The polymer that is soluble in the common household solvents should be present in the compositions of the present invention in an amount of from about 0% to about 60%, preferably about 1% to about 50% and most preferably about 2.0% to about 35% by weight based upon the total weight of the composition. In certain embodiments of the present invention, the polymer soluble in the common household solvents should exhibit a viscosity of at least 200 cps or less, preferably 100 cps or less and most preferably 50 cps or less when a 2% w/w of the material is added to water at 20°C.

In certain embodiments of the present invention the polymer that is soluble in common household solvent should be selected so it is soluble in as many of the common household solvents as possible. For example, the polymer that is soluble in common household solvents should be selected so it is soluble in water, ethanol, isopropyl alcohol, acetone or combinations thereof. Preferably the polymer that is soluble in common household solvents should be soluble in water, ethanol, isopropyl alcohol and acetone. More preferably, the polymer that is soluble in common household solvents should be soluble in water and either ethanol, isopropyl alcohol or acetone or combinations of the foregoing organic solvents.

In certain embodiments of the present invention the polymer that is soluble in common household solvents may comprise an amido-group, a tertiary amide group or an amino group. As used herein the terms "amido-group," "tertiary amide group," and "amino- group" are defined in U.S. Patent No. 6,558,659, entitled "Stable Pharmaceutical

Compositions Containing 7-Substituted-3,5-Dihydroxyheptanoic Acids or 7-Substituted-3,5- Dihydroxyheptenoic Acids" which are incorporated herein by reference.

In addition to the above-described abuse deterrent features, the compositions of the present invention may further comprise additional processing, stability enhancing and drug delivery excipients, such as taste-masking/flavoring agents, permeation enhancers, preservatives, pH modifying agents or buffering agents, dyes, fillers, and combinations thereof.

Additional information on the various excipients that may be used in the compositions of the present invention can be found in standard reference texts such as Remington, The Science and Practice of Pharmacy 21^st ed. pp. 1058-1092; United States Pharmacopeia 27 pp. 2809-2956, The Handbook of Pharmaceutical Excipients 5^th ed. and Martindale 33^rd ed., which are incorporated herein by reference. Representative examples of the various excipients employed in the embodiments of the present invention are provided below.

One or more taste-masking agents or flavoring agents may be used in the

compositions of the present invention to mask an undesired taste and/or odor. Suitable taste- masking agents and flavoring agents can be found in C.F.R. Title 21, Part 172, Subpart-F, which is hereby incorporated by reference in its entirety. Examples of suitable taste-masking agents and flavoring agents include, but are not limited to, sodium bicarbonate, ion exchange resin, cyclodextrin inclusion compound, adsorbent substance, SPLENDA®, saccharin sodium, sucrose, aspartame, acesulfame K, cyclamate, volatile oils, peppermint, menthol, and flavoring such as fruit, orange, cherry, grape, vanilla, mint, spearmint and mixtures of the foregoing. If present, the taste-masking/flavoring agent may comprise about 0.01% to about 25% of the composition, preferably between 0.1% to about 15% of the composition and most preferably about 0.5% to about 10% of the composition.

One or more permeation enhancers may be used in the compositions of the present invention. A permeation enhancer, sometimes referred to as a penetration enhancer, is a compound that can increase the permeability of a biological membrane to a drug, analyte, or other chemical molecule, compound, particle or substance. A permeation enhancer can increase the permeability of the NMDA receptor antagonist, preferably ketamine. Examples of permeation enhancers include, but are not limited to, sodium lauryl sulfate (SLS), alkylsaccharides, sodium salicylate, bile salts, sodium caprate, sodium laurate, capric acid, lauric acid, beta-cyclodextrin, cyclodextrin, DMSO, Tween-20, sodium tauroglycolate, and hyaluronidase. Other examples of permeability enhancers include, but are not limited to, 23- lauryl ether, sodium glycoholate, sodium glycodeoxycholate, sodium EDTA, Polysorbate 80, Cetylpyridinium chloride, cetyltrimethylammonium bromide, benzalkonium chloride, azone, sodium salicylate, sodium taurodeoxycholate, sulfoxides, various alkyl glycosides, menthol, aprotinin, dextran sulfate, lauric acid, lauric acid/propylene glycol, lysophosphatidylcholine, methoxysalicylate, methyl oleate, oleic acid, phosphatidylcholine, and polyoxyethylene. Further examples of permeability enhancers include, but are not limited to, ethylene-diamine tetra-acetic acid (EDTA), bile salt permeation enhancers, fatty acid permeation enhancers, acyl carnitines, and salicylates. If employed the permeation enhancer may comprise about 0.01% to about 20% percent of the compositions, preferably about 0.1% to about 10% of the compositions and most preferably about 0.5% to about 5% of the composition.

The composition may also comprise a preservative or anti-microbial agent. Examples of preservatives include, but are not limited to, benzalkonium chloride, methylparabens, and propylparabens. Suitable anti-microbial preservatives can be found in C.F.R. Title 21, Part 172, Subpart B, which is hereby incorporated by reference in its entirety.

The composition may also comprise pharmaceutically acceptable acids or bases to adjust the pH to a desired range. Pharmaceutically acceptable acids include hydrochloric acid, citric acid, fumaric acid, tartaric acid or mixtures thereof and pharmaceutically acceptable bases include sodium hydroxide, magnesium hydroxide, arginine, lysine, meglamine, triethanol amine or mixtures thereof. The pH of the composition, and particularly a liquid or semi-solid, may range between about 3.0 to about 9.0 and preferably about 4.0 to about 8.0. Buffering agents can also be used in the compositions to maintain a relatively constant hydrogen ion concentration. The buffering agent may also be added to enhance and/or maintain the NMDA receptor antagonist in the desired form. For example, a buffering agent such as sodium phosphate may be added to maintain S-ketamine

hydrochloride in an unprotonated form. An appropriate buffering agent may be selected from numerous known reagents including, for example phosphate, carbonate and bicarbonate systems such as sodium phosphate. If employed, the pH adjusting agent or buffering agent may comprise about 0.01% to about 20% percent of the compositions, preferably about 0.1% to about 10% of the compositions and most preferably about 0.5% to about 5% of the composition.

The composition may also comprise a coloring agent to make the composition more attractive in appearance, to help identify the product and as an indicator if the composition is unknowingly added to someone's drink at a club, bar or party. The coloring agent may also provide an additional abuse deterrent feature. If the coloring agent is soluble in a solvent that abusers typically employ to extract the drug from the dosage form, such as water, ethanol, isopropyl alcohol or acetone, the coloring agent will be extracted along with the drug by the abuser. The coloring agent will thereby impart an undesirable color to the extracted drug and hopefully deter the abuser from injecting or inhaling the exacted drug. Suitable coloring agents include, but are not limited to, any approved colorants, such as FD & C Blue No. 1 and FD & C Yellow No. 6. The composition may also comprise fillers sometimes referred to as diluents.

Examples of fillers include sugars such as lactose, dextrose, sucrose, maltose, or

microcrystalline cellulose, clays and mixtures thereof.

The compositions of the present invention may be administered by any route appropriate to the condition to be treated. Suitable routes include oral, buccal, sublingual, or rectal. It will be appreciated that the route used may vary with, for example, the condition of the recipient. The compositions of the present invention may be formulated into hard or soft gelatin capsules, suppositories, tablets or liquids. Examples of hard and soft gelatin capsule formulations can be found in European Patent Application No. 1 029 539 Al or U.S. Patent No. 7,435,427 which are incorporated herein by reference.

In certain embodiments, the composition is administered to a patient through the oral cavity, preferably by buccal or sublingual instillation. Buccal instillation is a method of administering a solid, liquid or semi-solid composition in the cavity between the gum and the cheek or directly onto the cheek mucosa. Sublingual instillation is a method of

administering a solid, liquid or semi-solid composition in the cavity under the tongue. One embodiment of the present invention comprises application of the solid, liquid or semi-solid composition by buccal and/or sublingual administration. The drug then enters the blood in the capillary bed by diffusion through the mucosal tissue and is distributed in the bloodstream to the rest of the body.

Compositions for administration to the buccal or sublingual cavity may be provided in a prefilled, unit dose delivery device. The unit dose delivery device may be a hard or soft gelatin capsule, a Blow-Fill-Seal packet or ampoule, a spray (aerosol or pump) wherein each actuation of the spray apparatus delivers a metered dose of the NMDA receptor antagonist. The unit dose delivery device may also be a foil-lined sealed packet. Alternatively, the unit dose delivery device may be a tube similar in design to a tooth paste tube or cake icing tube. In this embodiment a caregiver or patient will remove a cap from an appropriately sized tube that exposes an opening to the internal lumen of the tube containing the liquid composition. The caregiver will compress or squeeze the external walls of the tube to force the liquid composition from the tube and to the delivery site, such as the buccal cavity of the patient. Another embodiment of the unit dose delivery device employs a barrel/plunger type mechanism similar to a syringe (without a needle). In this embodiment, the liquid composition is filled into a barrel in a predetermined amount. The liquid composition is forced from one end of the barrel by applying force to a plunger contained within the barrel. The barrel may be formed or equipped with a soft or semi-rigid tip that allows a more focused and directional delivery of the liquid composition to the appropriate site of administration such as the buccal, sublingual or rectal cavity.

Certain embodiments of the present inventions are abuse deterrent compositions comprising:

a) about 2% to about 50%, preferably about 5% to about 25%, of ketamine, S- ketamine or a pharmaceutically acceptable salt thereof;

b) about 1% to about 50%, preferably about 5% to about 35%, of a material that gels when the composition is placed in an aqueous environment wherein the material that gels is selected from the group consisting of polyethylene oxide, polyvinyl alcohol, hydroxypropyl methylcellulose, hydroxylpropyl cellulose, carbomers and mixtures thereof;

c) optionally an aversive agent selected from the group consisting of a mucosal irritant, a bittering agent an emetic agent or combinations thereof;

d) a self-emulsifying component wherein the ketamine or S-ketamine is incorporated into the self-emulsifying component wherein the self-emulsifying component comprises:

i) about 5% to about 75%, preferably about 15% to about 65%, based upon the total weight of the abuse deterrent composition of a lipophilic excipient that is a liquid at temperatures of 37°C or less and exhibits a

hydrophilic/lipophilic balance (HLB) value of 7 or less; and

ii) about 1% to about 50%, preferably about 5% to about 35%, based upon the total weight of the abuse deterrent composition of a non-ionic surfactant that exhibits an HLB value of 10 or less;

e) about 1% to about 50%, preferably about 2.5% to about 20% of a polymer that is soluble common household solvents selected from the group consisting of water, ethanol, isopropyl alcohol, acetone, mineral oil and mixtures thereof; f) optionally a taste-masking or flavoring agent;

g) optionally a permeation enhancer; and

h) optionally a buffering agent. The amounts of items a-h are adjusted so they sum to 100%.

The self-emulsifying component of the above described abuse deterrent composition is preferably a SEDDS or SMEDDS.

The polymer that is soluble in the common household solvents in the above abuse deterrent composition may exhibits a viscosity of 200 cps or less when a 2% w/w solution of the material is added to water at 20°C. The polymer soluble in the common household solvents also prevents the material that gels when placed into an aqueous environment, i.e., the polyox, carbomer, hydroxypropyl cellulose or hydroxypropyl methylcellulose from agglomerating, which is turn makes the extraction of the NMDA receptor antagonist more challenging.

The above embodiment of the abuse deterrent composition may also be administered to patients, preferably human patients, to treat depression, restless leg syndrome, bipolar disorder or pain. The abuse deterrent composition may be administer orally, buccally, sublingually, or rectally, preferably orally, buccally or sublingually and comprise about 10 mg to about 200 mg based upon the free base equivalent, preferably about 15 mg to about 175 mg based upon the free base equivalent and most preferably about 20 mg to about 150 mg based upon the free base equivalent of S-ketamine or a pharmaceutically acceptable salt thereof. If the racemic mixture, i.e., ketamine or a pharmaceutically acceptable salt is employed, the forgoing amounts should be doubled.

In certain embodiments, the amount of S-ketamine should be administered in a manner that produces anti-depressant effects but not anesthesia. The target range to obtain anti-depressant effects should be an amount that obtains a plasma level of less than about 200 ng/mL, preferably less than about 150 ng/mL and most preferably less than about 100 ng/mL In an alternative embodiment, the target plasma level of S-ketamine should range between about 10 ng/ml and about 200 ng/mL, preferably between about 15 ng/mL and about 150 ng/mL and most preferably between about 20 ng/mL and 100 ng/mL. In certain patients, anti-depressant effects have been found wherein the S-ketamine plasma levels range from about 10 ng/mL to about 100 ng/mL, preferably from about 15 ng/mL to about 90 ng/mL and most preferably about 20 ng/mL to about 85 ng/mL. The foregoing plasma levels may be determined based upon a single dose fasting study in healthy volunteers or in patients.

The abuse-deterrent composition of the present invention may be administered in a manner that will obtain the desired therapeutic benefit. For example, in the treatment of depression, the composition may be administered once every 12 hours, once every 24 hours, once every 48 hours, once every 72 hours, once every 96 hours, once every 120 hours, once every 144 hours or once every 168 hours. In certain embodiments, when the abuse deterrent composition is administered for the treatment of depression, the composition may be administered once every 24 to 168 hours, preferably once every 48 hours to 168 hours or once every 72 to 168 hours. In certain embodiments, the amount of S-ketamine should be administered in a manner that produces anti-depressant effect and obtains a S-norketamine plasma level of less than about 500 ng/mL, preferably less than about 450 ng/mL and most preferably less than about 400 ng/mL In an alternative embodiment, the target plasma level of S-norketamine should range between about 10 ng/ml and about 500 ng/mL, preferably between about 25 ng/mL and about 450 ng/mL and most preferably between about 50 ng/mL and 400 ng/mL. The foregoing plasma levels may be determined based upon a single dose fasting study in healthy volunteers or in patients.

In certain embodiments, it is also desired that the S-ketamine or pharmaceutically acceptable salt be administered in an abuse-deterrent dosage form, preferably a sublingual or buccal dosage form that releases the S-ketamine or pharmaceutically acceptable salt in a manner and location of the patient's body that results in a time to maximum plasma concentration of S-ketamine, i.e., T_max of less than about 200 minutes, preferably less than about 180 minutes and most preferably less than about 150 minutes. In one embodiment, it is also desired that the S-ketamine or pharmaceutically acceptable salt be administered in an abuse-deterrent dosage form, preferably a sublingual or buccal dosage form, that releases the S-ketamine or pharmaceutically acceptable salt in a manner and location of the patient's body that results in a T_max range of about 20 minutes to about 200 minutes, preferably about 25 minutes to about 180 minutes and most preferably about 30 minutes to about 150 minutes. The foregoing T_max values may be determined based upon a single dose fasting study in healthy human volunteers or in patients.

In certain embodiments, it is also desired that the S-ketamine or pharmaceutically acceptable salt be administered in an abuse-deterrent dosage form, preferably a sublingual or buccal dosage form that releases the S-ketamine or pharmaceutically acceptable salt in a manner and location of the patient's body that results in an S-norketamine T_max of less than about 240 minutes, preferably less than about 200 minutes and most preferably less than about 180 minutes. In one embodiment, it is also desired that the S-ketamine or

pharmaceutically acceptable salt be administered in an abuse-deterrent dosage form, preferably a sublingual or buccal dosage form, that releases the S-ketamine or

pharmaceutically acceptable salt in a manner and location of the patient's body that results in an S-norketamine T_max range of about 30 minutes to about 240 minutes, preferably about 35 minutes to about 200 minutes and most preferably about 40 minutes to about 180 minutes. The foregoing T_max values may be determined based upon a single dose fasting study in healthy human volunteers or in patients. Certain embodiments of the present invention that are useful for treating depression may further comprise administering a pharmaceutically effective dose of a second agent, wherein the second agent is an antidepressant agent. The second agent may be any additional antidepressant agent. Exemplary antidepressant agents include but are not limited to at least one member of lithium, a pharmaceutical antidepressant, an herbal antidepressant, an anticonvulsant, a mood stabilizer, an antipsychotic agent, and a benzodiazepine. Some of the preferred second antidepressant agents are described in U.S. Published Patent Application No. 2007/0287753 which is incorporated herein by reference.

The above embodiment of the abuse deterrent composition also has the added benefit of muco-adhesion due to the presence of the recited polymers that gel when the composition is placed in an aqueous environment such as the buccal, or sublingual cavity. This muco- adhesive feature allows the composition to adhere to the mucosa of the buccal or sublingual cavity of the patient and reduce the patient's tendency to swallow the composition before the ketamine, S-ketamine or a pharmaceutically acceptable salt thereof has been released and absorbed through the mucosa of the buccal or sublingual cavity.

The abuse deterrent compositions of the present invention that comprise self- emulsifying component will become milky when diluted with an aqueous medium, thereby further discouraging the drug-abuser from injecting the adulterated dosage form. In addition, the self-emulsifying components, especially a SEDDS or SMEDDS will be extracted into almost any solvent typically used by a drug abuser, including water, ethanol, isopropyl alcohol and acetone. The extraction of the self-emulsifying component with the NMDA receptor antagonist will make recrystallization of the extracted material to pure drug powders for either snorting or injection more difficult.

The abuse deterrent properties of the present invention may be determined by any methods described in the literature. One such method comprises adding the abuse deterrent composition, i.e., the unit dosage form, to an excess amount of a common household solvent as previously described, mixing or shaking the combination and analyzing an extract of the common household solvent from combination to determine the amount of NMDA receptor antagonist, preferably ketamine or S-ketamine, that is present in the extracted household solvent. The lower the amount of NMDA receptor antagonist in the extracted solvent, the more abuse resistant the composition. One embodiment of this methodology comprises adding a predetermined amount of the abuse deterrent composition, such as a 500 mg tablet, capsule or paste comprising the NMDA receptor antagonist, to an appropriately size container along with an excess amount of a common household solvent. Preferably the solvent is added in an amount that is about ten times the weight of the abuse deterrent composition. For example, if the abuse deterrent composition is 500 mg, approximately solvent 5,000 mg of a common household solvent, such as acetone is added. The combination is mixed or shaken and after an appropriate time period, such as about 5 to 30 minutes, the solvent is extracted and analyzed to determine the amount of NMD A receptor antagonist in the extracted solvent. The amount of NMD A receptor antagonist in the extract solvent should be less than 5% of the total amount of the NMDA receptor antagonist present in the abuse deterrent composition, preferably less than 2.5% of the total amount of the NMDA receptor antagonist present in the abuse deterrent composition and most preferably less than 1% of the total amount of the NMDA receptor antagonist present in the abuse deterrent composition. Embodiments of the present invention should exhibit the afore- described extraction limitations in more than one of the common household solvents. For example, the abuse deterrent compositions of the present invention should allow less than 5%, preferably less than 2.5% and most preferably less than 1% of the total amount of the NMDA receptor antagonist present in the dosage form to be extract into water and less than 5%, preferably less than 2.5% and most preferably less than 1% of the total amount of the NMDA receptor antagonist present in the dosage form to be extract into an organic solvent such as ethanol, isopropyl alcohol, acetone, mineral oil or combinations thereof.

It has also been discovered that the abuse deterrent compositions of the present invention that comprise high molecular weight hydrophilic polymers, especially polyox, polyvinyl alcohol, carbomers, hydroxypropyl methylcellulose and hydroxypropyl cellulose, which swell extensively in aqueous media and ethanol can be formulated along with the self- emulsifying component to release at least 90% of the NMDA receptor antagonist in 90 minutes or less, preferably 60 minutes or less and most preferably in about 30 minutes or less when the abuse deterrent compositions are tested in a USP Type II apparatus with an aqueous media.

Examples

The following examples are put forth so as to provide those of ordinary skill in the art with a complete disclosure and description of how to make and use the embodiments, and are not intended to limit the scope of what the inventors regard as their invention nor are they intended to represent that the experiments below are all or the only experiments performed. Efforts have been made to ensure accuracy with respect to numbers used (e.g., amounts, temperature, etc.) but some experimental errors and deviations should be accounted for. EXAMPLE 1

A buccal/sublingual abuse deterrent composition is prepared in accordance with the present invention having the following composition:

The above composition is prepared by suspending the S-Ketamine powder in a mixture of the linoleoyl polyoxyglycerides and sorbitan monooleate. The sucralose, copovidone and carbomer homopolymer are gradually added to the suspension while mixing. The final composition is a paste and is filled into appropriately sized glass syringes with a plunger stopper and plunger rod.

EXAMPLE 2

S-Ketamine 2.00 g 20.00 20.00 Hydrochloride

Linoleoyl 4.94 g 49.40 49.40 Polyoxyglycerides

(LABRAFIL

M2125CS)

Carbomer 1.14 g 1 1.42 1 1.42 Homopolymer Type

B

(CARBOPOL®

974P)

Sorbitan Monooleate 1.14 g 11.42 1 1.42 (SPAN 80)

Copovidone 0.41 g 4.10 4.10 (Kollidon® VA64)

Menthol, USP 0.05 g 0.50 0.50

Sucralose NF 0.05 g 0.50 0.50 (Splenda®)

Sodium Lauryl 0.16 g 1.58 1.58

Sulfate

Sodium Phosphate 0.16 g 1.58 1.58 Dibasic, Anhydrous

EXAMPLE 3

A buccal/sublingual abuse deterrent composition containing 45 mg of S-ketamine is prepared in accordance with the present invention having the following composition:

(Splenda®)

Copovidone 4.34 21.7 20.0 (Kollidon® VA64)

Carbomer 18.00 90.0 83.1 Homopolymer Type

B

(CARBOPOL®

974P)

Total 100.0 500.0 461.4

51.9 mg of S-ketamine hydrochloride is equivalent to 45 mg of its free base.

The above composition is prepared by suspending the S-Ketamine powder in a mixture of the linoleoyl polyoxyglycerides and sorbitan monooleate. The sucralose, copovidone and carbomer homopolymer are gradually added to the suspension while mixing. The final composition is a paste and is filled into 1.0 mL long luer lock glass syringes with Datwyler FM 257/2 plunger stopper and 1 mL long polypropylene plunger rod.

EXAMPLE 4

A buccal/sublingual abuse deterrent composition containing 90 mg of S-ketamine is prepared in accordance with the present invention having the following composition:

(Kollidon® VA64)

Carbomer 10.87 54.3 50.1 Homopolymer Type

B

(CARBOPOL®

974P)

Total 100.0 500.0 461.4

103.8 mg of S-ketamine hydrochloride is equivalent to 90 mg of its free base.

The above composition is prepared and filled into appropriately sized syringes according to the procedure described for Example 3.

EXAMPLE 5

A buccal/sublingual abuse deterrent composition containing 135 mg of S-ketamine prepared in accordance with the present invention having the following composition:

974P)

Total 100.0 500.0 461.4

* 155.7 mg of S-ketamine hydrochloride is equivalent to 135 mg of its : ree base.

The above composition is prepared and filled into appropriately sized syringes according to the procedure described for Example 3. EXAMPLE 6

The compositions of Examples 3 and 4 were administered to healthy human volunteer subjects between the ages of 18 and 47 years, in a single-center, single-dose, randomized, four treatment, crossover study. Twenty-four (24) subjects [14 males, 10 females] were enrolled. Each subject received a single dose of the following treatments at approximately 8:00 a. m. after an approximately 10 hour overnight fast:

Treatment 1, the 461.4 mg sublingual paste (comprising 90 mg eq. of S-ketamine free base) of Example 4retained under the tongue for two (2) minutes;

Treatment 2, the 461.4 mg sublingual paste (comprising 90 mg eq. of S-ketamine free base)of Example 4 with no restriction on retention under the tongue of swallowing;

Treatment 3, the 461.4 mg sublingual paste (comprising 45 mg eq. of S-ketamine free base) of Example 3 retained under the tongue for two (2) minutes; and

Treatment 4, 15 mg (free base equivalent of S-ketamine) I.V. (KETANEST-S® a commercially available form of S-ketamine marketed by Eurocept Pharmaceuticals in Europe which comprises 25 mg/ml of S-ketamine) administered over 40 minutes.

The sublingual pastes were administered under the subject's tongue by use of the prefilled syringe (applicator). The subjects were not allowed to expectorate, drink, or rinse the mouth for at least one hour post dose. Subjects were not allowed to eat until

approximately 2 hours after dosing. A minimum of a five (5) day washout period was required between the dosing of each treatment.

Plasma samples were collected within one hour predose and postdose at 10, 20, 30, 40 and 50 minutes and at 1, 1.5, 2, 3, 4, 6, 8, 12, and 24 hours. The plasma samples were obtained by collecting approximately 6 mL of blood in a K₂-EDTA treated tubes at each time point. The plasma was fractionated from the blood sample within 60 minutes of collection by centrifugation for about 15 minutes at 3400 rpm. The plasma samples were transferred via a pipette into polypropylene tubes containing ΙΟΟμί of 10% (v/v phosphoric acid solution and stored at -70°C until shipment for analysis. The resultant plasma samples were analyzed for S-ketamine, S-norketamine and S-dehydronorketamine concentrations by a validated liquid chromatography-tandem mass spectrometry (HPLC-MS/MS) method. The

pharmacokinetics of this study may be summarized as follows:

S-Ketamine

(mean ±SE, median (range) for T_max)

(%)

S-Hydroxynorketamine

(mean ±SE, median (range) for T_max)

EXAMPLE 7

A buccal/sublingual abuse deterrent composition containing 30 mg of S-ketamine is prepared in accordance with the present invention having the following composition:

Homopolymer Type

B

(CARBOPOL®

974P)

Total 100.0 200 173.00

*34.60 mg of S-ketamine hydrochloride is equivalent to30 mg of its free base.

EXAMPLE 8

An oral abuse deterrent capsule containing 30 mg of S-ketamine is prepared in accordance with the present invention having the following composition:

*34.60 mg of S-ketamine hydrochloride is equivalent to 30 mg of its free base.

The above composition is prepared according to the procedure described for Example 3 and filled into 00 size gelatin capsules. EXAMPLE 9

34.60 mg of S-ketamine hydrochloride is equivalent to 30 mg of its free base

The above composition is prepared according to the procedure described for Example 3 and filled into capsules as described in Example 8.

EXAMPLE 10

The compositions of Examples7-9 were administered to healthy human volunteer subjects between the ages of 19 and 49 years in a single-center, single-dose, randomized, four treatment, crossover study. Twenty-four (24) subjects [1 1 males, 13 females] were enrolled and twenty (20) subjects completed all four treatment periods. Each subject received a single dose of the following dosage forms at approximately 8:00 a.m. after approximately a 10 hour overnight fast:

Treatment 1, the 173 mg sublingual paste (comprising 30 mg eq. of S-ketamine free base) of Example 7;

Treatment 2, the 173 mg capsule (comprising 30 mg eq. of S-ketamine free base) of Example 8;

Treatment 3, the 173 mg capsule (comprising 30 mg eq. of S-ketamine free base) of Example 9; and

The capsules were administered with approximately 240 mL of water. The capsules were swallowed intact and the sublingual paste was applied under the subject's tongue and was swallowed approximately 2 minutes after administration. Subjects were not allowed to eat until approximately 4 hours after dosing. The subjects were not allowed to expectorate, drink, or rinse the mouth for at least 1.5 hours post dose. A seven day washout period was required between the dosing of each test material.

A total of 15 plasma samples were collected within 60 minutes predose and postdose at 10, 20, 30, 40 and 50 minutes and at 1, 1.5, 2, 3, 4, 6, 8, 12, and 24 hours. The plasma samples were obtained by collecting approximately 6 mL of blood in a K2-EDTA treated tuber at each time point. The plasma was fractionated from the blood sample within 60 minutes of collection by centrifugation for about 15 minutes at 3400 rpm. The plasma samples were transferred via a pipette into polypropylene tubes containing ΙΟΟμΕ of 10% (v/v phosphoric acid solution and stored at -70°C until shipment for analysis. The resultant plasma samples were analyzed for S-ketamine and potential metabolite concentrations by a validated liquid chromatography-tandem mass spectrometry (LC-MS/MS) method. The pharmacokinetics of this study may be summarized as follows:

Cmax (ng/mL) 84.5 (24.9) 32.2 (7.15) 17.7 (8.88) 18.9 (9.20) t½ (h) 7.16 (2.71) 4.1 (1.37) 2.86 (1.61) 3.21 (2.32)

AUCo-last 182.7 (34.3) 69.8 (24.5) 35.6 (18.2) 40.4 (18.6)

(ng*h/mL)

AUCo-_∞ 195.6 (41.2) 74.7 (25.2) 38.7 (9.53) 43.7 (20.1) (ng*h/mL)

Bioavailability — 19.1 9.9 1 1.2

(%)³

All values (except T_max) are mean ±SD in subjects who received all four treatments.

² Median (range).

³ Estimated from AUC values to the IV dose. The CNS-related adverse events were recorded for the twenty (20) subjects that completed all four treatments and are summarized in the following table:

The psychiatric responses of the four treatments were measured at predose and post dose using Brief Psychiatric Rating Scale-Positive Symptoms (BPRS) and Clinician

Administered Dissociative Stated Scale (CADSS). The BPRS test is a measure of psychotic symptoms and the CADSS is a measure of dissociative symptoms.

The BPRS was administered in all subjects through all the Periods (Treatments A, B, C and D), scheduled at predose and postdose at 30 minutes, 1, 2, 3, 6, 12, and 32 hrs.

Whenever possible, the BPRS was administered by the same trained clinician to a subject throughout the study to assess the psychiatric effects. The BPRS consisted of 18 symptom constructs which included 1 = Somatic Concern; 2 = Anxiety; 3 = Emotional Withdrawal; 4 = Conceptual Disorganization; 5 = Guilty

Feelings; 6 = Tension; 7= Mannerisms and Posturing; 8 = Grandiosity; 9 = Depressive Mood; 10 = Hostility; 11 = Suspiciousness; 12 = Hallucinatory Behavior; 13 = Motor Retardation; 14 = Uncooperativeness; 15 = Unusual Thought Content; 16 = Blunted Affect; 17 =

Excitement; 18 = Disorientation.

Each symptom was scored by entering a number which would best describe the subject's condition where 0 = not assessed; 1 = not present; 2 = very mild; 3 = mild; 4 = moderate; 5 = moderately severe; 6 = severe; 7 = extremely severe.

The total score for each subject was recorded as the sum of the scores of the 18 items at each time-point. The total score was compared from one evaluation to the next as the measure of response to treatment.

Following the IV treatment, mean peak BPRS Total Score was observed 1 hour after the start of infusion and returned to mean predose values by approximately 1 hour after the end of infusion. The summary mean (± SD) for BPRS Total Score recorded was 18.5±1.3 at predose, 18.4±1.3 at lhr, and 18.2±0.9 at 3hrs for Treatment A; 18.8±2.0 at predose, 18.7±1.6 at lhr, and 18.4±1.0 at 3hrs for Treatment B; 18.4 ±1.3 at predose, 18.4±1.1 at lhr, and 18.2±0.5 at 3hrs for Treatment C and 18.7±1.8 at predose, 20.5±9.1 at lhr, and 18.1±0.7 at 3hrs for Treatment D.

The CADSS was administered in all subjects through all the Periods (Treatments A,

B, C and D), scheduled at predose and postdose at 30 minutes, 1, 2, 3, 6, 12, and 32 hrs. Whenever possible, the CADSS post dose was administered by the same trained clinician to a subject throughout the study to assess the dissociative symptoms.

The CADSS consisted of a 27-item scale with a subjective and an observer component. The subjective component consisted of 19 items, which were administered by a clinician who began each question with the phrase "at this time" and then read the item to the subject while the observer component consisted of 8 behavioral items which were consistent with the presence of a dissociative state. The foregoing was assessed by the patient for the subjective components and the clinician for the observer component where 0 = not at all, 1 = slightly, 2 = moderately, 3 = considerably, 4 = extremely.

Following the IV treatment, mean (± SD) peak CADSS Total Score of 14.9±25.6 occurred 30 min after the start of infusion and returned to predose values by approximately 5 hours after the end of infusion. Following Treatment A, B, and C, mean (± SD) peak CADSS Total Score of 1.0±2.8, 1.5±4.7, and 4.1±12.0 were noted at 30 min, lhr, and 30 min, respectively after dosing. The total scores returned to predose values by approximately 2-3 hours after each of the three test formulations were administered. The summary mean (± SD) for CADSS Total Score recorded at predose was 0.2±1. lwhile it was 0.2±0.7at 3hrs for Treatment A; 0.2±0.5 at predose and 0.1±0.2 at 3hrs for Treatment B; 0.4±1.0 at predose and 0.7±2.3 at 3hrs for Treatment C, and 0 at predose and 0.9±4.0 at 32hrs for Treatment D.

A more detailed description of the BPRS methodology can be found in Overall et al, "The Brief Psychiatric Rating Scale," Psychol Rep. 1962; 10: 799-812 which is incorporated herein by reference. A more detailed description of the CADSS methodology can be found in Journal of Traumatic Stress. 1998; 1 1(1): 125-36 and J. Douglas Bremmer, M.D., Emory University, March 4, 2014, "The Clinician Administered Dissociative States Scales (CADSS) Instructions for Administration" which are incorporated herein by reference.

EXAMPLE 11

The following compositions were prepared and tested to determine the amount of S- ketamine that could be extracted with acetone:

(CARBOPOL®

974P)

Total 41 1.1 443.3 461.4

Compositions A, B and C were added to approximately 10 times their weight of acetone.

Composition A (containing the water and acetone soluble polymer, copovidone), separated into two phases upon the addition of acetone. The acetone phase could be easily decanted, dried and concentrated S-ketamine obtained.

Compositions B (without the water and acetone soluble polymer, copovidone), separated into two phases upon the addition of acetone. The acetone phase could be easily decanted, dried and concentrated S-ketamine obtained.

Composition C (containing the water and acetone soluble polymer, copovidone and the gelling carbomer) formed two phases that could not be easily separated upon the addition of acetone. The mixture of Composition C and acetone was centrifuged at 2500 rpms for 10 minutes which allowed the acetone to be extracted. High Performance Liquid

Chromatography (HPLC) analysis of the acetone phase obtained from centrifugation contained about 0.4% of the total S-ketamine in Composition C.

EXAMPLE 12

Composition C described in Example 1 1 above was added to approximately 10 times its weight of 0.2 N HC1 (acidified water). The resulting mixture was vigorously shaken resulting in a milky gel. The mixture was allowed to stand and samples of the water phase were extracted and analyzed by HPLC. After four hours the aqueous phase was reduced due to the absorption by the carbomer. Prior to the four hour time point, when water was available for extraction, the amount of S-ketamine in the water was less than about 0.7 %of the total S-ketamine in Composition C.

The invention illustratively described herein suitably may be practiced in the absence of any element or elements, limitation or limitations which is not specifically disclosed herein. Thus, for example, in each instance herein any of the terms "comprising," "consisting essentially of and "consisting of may be replaced with either of the other two terms. The terms and expressions which have been employed are used as terms of description and not of limitation, and there is no intention in the use of such terms and expressions of excluding any equivalents of the features shown and described or portions thereof, but it is recognized that various modifications are possible within the scope of the invention claimed. Thus, it should be understood that although the present invention has been specifically disclosed by preferred embodiments and optional features, modification and variation of the concepts herein disclosed may be resorted to by those skilled in the art, and that such modifications and variations are considered to be within the scope of this invention as defined by the appended claims.

Claims

WHAT IS CLAIMED IS:

1. An abuse deterrent composition comprising:

a) an NMDA receptor antagonist and

b) at least one or more of the following abuse deterrent features:

i) a material that gels when the composition is placed in an aqueous environment;

ii) an aversive agent selected from the group consisting of a mucosal irritant, a bittering agent, an emetic agent and combinations thereof; iii) a self-emulsifying component wherein the NMDA receptor antagonist is incorporated into the self-emulsifying component; and

iv) a polymer soluble in common household solvents selected from the group consisting of water, ethanol, isopropyl alcohol, acetone, mineral oil and mixtures thereof.

2. The abuse deterrent composition of claim 1 wherein the NMDA receptor antagonist is ketamine, S-ketamine or pharmaceutically acceptable salts thereof.

3. The abuse deterrent composition of claim 2 wherein the NMDA receptor antagonist is S-ketamine hydrochloride.

4. A method for treating depression, restless leg syndrome, bipolar disorder or pain comprising the step of administering the abuse deterrent composition of claim 1 to a patient.

5. The method of claim 4 wherein the abuse deterrent composition is administered orally, buccally, sublingually or rectally.

6. The method of claim 5 wherein the abuse deterrent composition is administered buccally or sublingually.

7. An abuse deterrent composition comprising:

a) about 2% to about 50%, preferably about 5% to about 25%, of ketamine, S- ketamine or a pharmaceutically acceptable salt thereof; b) about 1% to about 50%, preferably about 5% to about 35%, of a material that gels when the composition is placed in an aqueous environment wherein the material that gels is selected from the group consisting of polyethylene oxide, polyvinyl alcohol, hydroxypropyl methylcellulose, hydroxylpropyl cellulose, carbomers and mixtures thereof;

i) about 5% to about 75%, preferably about 15% to about 65%, based upon the total weight of the abuse deterrent composition of a lipophilic excipient that is a liquid at temperatures of 37°C or less and exhibits a hydrophilic/lipophilic balance (HLB) value of 7 or less; and ii) about 1% to about 50%, preferably about 5% to about 35%, based upon the total weight of the abuse deterrent composition of a non-ionic surfactant that exhibits an HLB value of 10 or less;

e) about 1% to about 50%, preferably about 2.5% to about 20% of a polymer that is soluble common household solvents selected from the group consisting of water, ethanol, isopropyl alcohol, acetone and mixtures thereof;

f) optionally a taste-masking or flavoring agent;

g) optionally a permeation enhancer; and

h) optionally a buffering agent.

8. A method for treating depression, restless leg syndrome, bipolar disorder or pain comprising the step of administering the abuse deterrent composition of claim 7 to a patient orally, buccally, sublingually or rectally.

9. The method of claim 8 wherein the abuse deterrent composition is administered buccally or sublingually.

10. The method of claim 7 wherein the abuse deterrent composition comprises about 1 mg to about 200 mg based upon the free base equivalent of S-ketamine or a pharmaceutically acceptable salt thereof.

11. The method of claim 10 wherein the S-ketamine is released in a manner to obtain an S-ketamine plasma level of less than about 200 ng/mL.

12. The method of claim 1 1 wherein the S-ketamine plasma level is between about 10 ng/ml and about 200 ng/mL.

13. The method of claim 10 wherein the S-ketamine is released in a manner to obtain an S-norketamine plasma level of less than about 500 ng/mL.

14. The method of claim 13 wherein the S-norketamine plasma level is between about 10 ng/ml and about 500 ng/mL.

15. The method of claim 9 wherein the S-ketamine or pharmaceutically acceptable salt is released in a manner to obtain a time to maximum plasma concentration of S- ketamine, (T_max) of less than about 200 minutes.

16. The method of claim 15 wherein the T_max is obtained from about 20 minutes to about 200 minutes.

17. The method of claim 9 wherein the S-ketamine or pharmaceutically acceptable salt is released in a manner to obtain a time to maximum plasma concentration of S- norketamine (T_max) of less than about 240 minutes.

18. The method of claim 17 wherein the T_max is obtained from about 30 minutes to about 240 minutes.

19. The method of claim 9 wherein the dosage form is administered once every 72 to 168 hours.