US2921883A - Novel coating material for medicaments - Google Patents

Description

United States Patent 2,921,883 Patented Jan. 19, 1960 NOVEL COATING MATERIAL FOR MEDICAlVIENTS N Drawing. Application May 3, 1957 Serial No. 656,750

14 Claims. (Cl. 167-82) and Joseph V. Swin- Pa., assignors to Smith, Kline 8: Philadelphia, Pa., a corporation This invention relates to a new coating material useful for prolonging the release of a medicament upon oral ad ministration and medicaments coated with said material.

The coating material of this invention is useful for coating medicaments using any of the conventional coat ing techniques. For example, it can be used to coat medicament pellets employing a coating pantechnique; it can be used to form a pellet of the coating material with the medicament dispersed therein; or a dispersion of medicament in the coating material can be spray dried to coat the medicament.

Th coating of small medicament-containing pellets with a fatty material or a fatty material admixed with a waxy material in order to obtain pellets with a size of the order from 0.1 to 2.0 mm. in diameter is known to the art. These pellets are encapsulated and administered to humans to provide for sustained release of the medicament over a long period of time, from about eight to ten hours.

, The manufacture of such coated pellets has been complicated by the small size of the pellets and the critical nature of the thickness of the coating in order to obtain a proper release of medicament. Complicating the picture further was the fact that the previous coating materials, for instance glyceryl monostearate and beeswax, due to solid state changes of the coatings, such as microcrystallization, i.e. changes of one crystalline form to another, teuded to alter the release of the medicament over a period of time, such as slowing down the medicament release. Therefore, in order to solve this problem and obtain products with reliable sustained release characteristics, complicated aging and blending techniques had to be employed. It is an object of this invention to provide a coating material which eliminates these problems.

Further, use of the coating material of this invention enables a continuous application of the coating material to the pellets to be employed during the manufacturing process, a great advantage over the multi-coating procedures of the prior art.

The coating material of this invention comprises an intimate mixture of a nontoxic, solid hydroxylated lipid material and a nontoxic, solid cellulose derivative. Exemplary of the lipid material are fatty alcohols having from 12 to 31 carbon atoms, such as for instance lZ-hydroxystearyl alcohol, lO-hydroxystearyl alcohol, 9,10-dihydroxystearyl alcohol, 14-hydroxybehenyl alcohol, lauryl alcohol, ceryl alcohol, carnubyl alcohol, stearyl aoohol, myricyl alcohol, behenyl alcohol, cetyl alcohol, myristyl alcohol or arachyl alcohol; fatty mono, di or triesters of glycols and glycerols which have at least one free hydroxy group and are derived from fatty acids of from 12 to 22 carbons, such as glyceryl distearate, glyceryl monostearate, propylene glycol monolaurate, ethylene glycol monopalmitate, ethylene glycol mono-lZ-hydroxystearate glyceryl monobehenate, glyceryl monocaprate, glyceryl didecanoate, propylene glycol monomyristate, glyceryl monol Z-hydroxystearate, glyceryl tri-12-hydroxystearate,

propylene di-IZ-hydroxystearate, ethylene glycol di-9,10-

dihydroxystearate, glyceryl tri-dihydroxystearate, glyceryl mono-12-hydroxystearate, glyceryl di-12-hydroxystearate, glyceryl di-ll-hydroxypalmitate, glyceryl mono-l6-hydroxystearate, glyceryl tri-lZ-hydroxylaurate, glyceryl trialeurate or glyceryl monostearate di-lZ-hydroxystearate.

Solid esters of either fatty hydroxy acids with lower aliphatic alcohols or fatty polyhydric alcohols with lower aliphatic acids, the said esters having a total carbon content of from 12 to 62 carbon atoms are also of value in this combination. Exemplary of such compounds are propyl 9,10-dihydroxystearate, dodecyl 9,10-dihydroxystearate, IZ-hydroxystearyl butyrate, IZ-hydroxystearyl palmitate, octadecyl 9,10-dihydroxystearate', propyl 13,14- dihydroxybehenate, or octadecyl 12-hydroxylaurate.

Advantageous compounds are glyceryl tri-l2-hydroxy stearate, glyceryl di-lZ-hydroxystearate, glyceryl mono- IZ-hydroxystearate, behenyl alcohol, stcaryl alcohol and l2-hydroxystearyl alcohol. A preferred substance is hydrogenated castor oil whose major component is glycryl tri-lZ-hydroxystearate.

Exemplary of the cellulose derivative of the combination of this invention are cellulosic ethers, such as ethyl cellulose, methyl cellulose, propyl cellulose; cellulosic esters, such as cellulose acetate, cellulose acetate butyrate, cellulose propionate, cellulose caprate, cellulose acetate propionate or cellulose acetate stearate.

The cellulose derivatives preferably are those in which the R moiety of cellulose-R is either an aliphatic acyl of 2 to 22 carbons'or an aliphatic alkyl of from 1 to 5 carbons.

The water insoluble cellulose derivatives are of particular advantage. Advantageous and preferred cellulosic derivatives are ethyl cellulose and cellulose acetate butyrate.

The components of the coating material are mixed either by melting the constituents together with intimate mixing or preferably by dissolving the constituents in an organic solvent in which they are sufiiciently soluble, such as carbon tetrachloride, ethylene dichloride, chloroform, ethyl acetate or benzene, then evaporating the solvent. T he ratio by weight of lipid material to cellulosic material may be varied widely, such as from 1:1 to 20:1. Preferably, proportions about 1:1 to about 9:1 are used. A particularly useful combination is hydrogenated castor oil of which the major constituent is glyceryl tri-12-hydroxystearate and ethyl cellulose preferably in proportions of about 4:1.

The coating material can be dissolved, usually in about 10% solution, in a suitable organic solvent, such as chloroform or alcohol-chloroform mixture and gradually applied by continuous spraying or vaporizing to the medicament-containing pellets which are agitated as the coating material is applied, such as in a coating pan. The pellets are then dried. If desired, the coating material can be applied in successive coats by alternately spraying or vaporizing to the pellets and drying until the de sired number of coats have been applied. It is preferred to have the coating a minimum of 2% by weight of the coated pellets. Advantageously the coating will be 5% to 15% by weight of the coated pellets.

Where it is desirable to have the medicament which is coated with the coating material of this invention in a finely divided form, for example, about 500 microns (U.S. 35 mesh) or smaller in size, the medicament in comminuted form mesh (U.S.) or smaller] is suspended in a volatile solution of the coating material, for example, the coating material in an organic solvent such as chloroform. The thus formed suspension is then spray dried to form dry treated particles substantially coated with the coating material. This spray drying may be carried out in apparatus conventionally used for spray drying and-which is well known tothe art. The spray drying conditions may vary. within wide ranges. however, preferred to use an inlet temperature of the spraying chamber of not more than about 150 C. and an outlet temperature of the spraying chamber of not less than about 50 C. The spray dried material may be used as such or, if desired, can be compressed into a. tablet.

Similarly, the coating material of this invention can be employed to provide for a sustained release of medicament by molding pellets using a dispersion of the selected medicament in a melt of the coating material of this invention, this admixture being formed in suitable molds.

The sustained release coating of this invention provides satisfactory sustained release rates of medicament in the gastrointestinal tract. It will be understood that this susained release of medicament over a period of many hours differs from the result achieved with enteric coatings which protect the medicament during passage through the stomach and then releases all of the medicament at substantially one time.

Further the sustained released rates are maintained well upon aging. Since the coatings are not very pH sensitive, the medicament release is not affected by the emptying time of the stomach and the varying pl-l caused thereby. Further, the coatings of this invention are harder than the previously used glyceryl stearate-wax mixtures. For this reason the coated pellets are less liable to distortion in the coating pans as Well as more resistant to injury by shock during subsequent commercial handling. In addition the coatings of this invention are less subject to cracking caused by extreme temperature changes, such as from near zero conditions often encountered while shipping to the room temperature conditions of storage.

Pharmaceutical preparations having a medicament coated with the coating material of this invention give good sustained release of medicament with a thinner coat than is possible with the prior art combinations. This is reflected in shorter operating times on each batch of pellets, thereby saving man and machine power as well as coating material.

The variations possible in utilizing the coating combination of this invention will be more apparent from consideration of the following examples:

Example I pan is set in rotation and one-third of the alkaloid coating solution is added by slowly pouring it onto the pellets in order to wet them evenly. Then 400 gm. of coating powder, containing equal parts of starch and sugar, are sprinkled on the wetted mass of nonpareil seeds. The pellets are dried in warm air. The addition of the alka- 'loid solution, starch-sugar coating powder and the drying procedure are repeated to apply two additional coats. Two final coatings are added, each coat consisting of 350 ml. of syrup U.S.P. The pellets are thoroughly dried It is, I

The remainder ofthe batch, containing three-fourths of the coated pellets, further is coated with 1.5 1. of fat and screened through a #16 mesh screen and on a #25 V mesh screen. The yield is approximately 20 kg.

The screened pellets are returned to a coating pan and coated with a fat-cellulosic coating solution made by admixing l000 gm. of hydrogenated castor oil, 250 gm. of ethyl cellulose and sufiicient chloroform to make 12.5 liters. Ten liters of the solution are applied in a continuous manner at room temperature. After applying the cellulose solution. After applying the solution, the pellets are dried with air and two-thirds of the remaining batch removed.

The remainder of the batch, containing one-fourth of the original pellets, is further coated with 1.0 l. of fatcellulose solution. After applying the solution, the pellets are dried with air.

The three groups of pellets thus formed are placed in a single container and thoroughly mixed to provide a uniform mixture. Size No. 4 gelatin capsules are then filled with the thus mixed pellets to provide a total dosage of 0.4 mg. of mixed alkaloids per capsule. Each capsule contains about 350 pellets.

Each No. 4 capsule provides the desired body level of belladonna alkaloids in about one-half hour. The coated pellets continue to provide sufficient belladonna alkaloids to maintain this desired body level for approximately ten hours.

Example ll Pellets coated "with belladonna alkaloids and overcoated with syrup are prepared and screened as in Example I. The screened pellets, approximately 20 kg., are returned to a coating pan and coated with 12 l. of a fat-cellulosic coating solution made by admixing 1000 gm. of hydrogenated castor oil, 250 gm. of ethyl cellulose and sufficient chloroform to make 12.5 liters.

The coating solution is applied gradually and con tinuously until the coating operation is completed. The pellets are dried with air and screened through a #16 mesh screen and on a #25 mesh screen. The pellets are thoroughly mixed and filled into size No. 4 gelatin capsules to provide a total dosage of 0.4 mg. of mixed alkaloids per capsule. Each capsule contains about 350 pellets. Each No. 4 capsule provides the desired body level of belladonna alkaloids in about one-half hour. The coated pellets continue to maintain this desired body level for approximately ten hours.

- Example Ill Nonpareil seeds (sugar pellets), 18.3 kg., like those used in Example I are placed in a 36-inch coating pan. A coating solution is prepared by dissolving 1.2 kg. of chlorprophenpyridamine maleate in 2.3 l. of 10% gelatin solution; The pan is set in rotation and approximately ml. of the coating solution is added by slowly pouring over the pellets to evenly wet them. The pellets are dried in warm air. The addition of the coating solution and the drying procedure are repeated until the solution is exhausted. When all of the coating solution has been applied, two final coats consisting of 150 ml. syrup U.S.P. are applied. The pellets are thoroughly dried and screened through a #16 mesh screen and a #25 mesh screen. The yield is approximately 20 kg.

The screened pellets are returned to a coating pan and coated with the fat-cellulosic coating solution as in Example I.

The three groups of pellets thus formed are placed in a single container and thoroughly mixed to provide a uniform mixture.

Size No. 3 gelatin capsules are then filled with the thus mixed pellets to provide a total dosage of 8 mg. of chlorprophenpyridamine maleate per capsule. Each capsule contains about 450 pellets.

Each No. 3 capsule provides the desired body level of chlorprophenpyridamine maleate in about one-half sule. contains about .450 pellets.

I Example IV I A Pellets coated with chlorprophenpyridamine maleate and overcoated with syrup are prepared and screened as in Example III. The yield is 20 kg.

Eighteen kilograms of the screened pellets are returned to a coating pan and coated with 10.8 1. of a fat-cellulosic coating solution made by admixing 1000 gm. of hydrogenated castor oil, 250 gm. of ethyl cellulose and sufiicient chloroform to make 12.5 liters. The coating solution is applied gradually and continuously until the coating operation is completed. The pellets are dried with air and screened through a #16 mesh screen and on a #25 mesh screen.

The remaining 2 kg. of the originally produced pellets overcoated with syrup are screened through a #16 mesh screen and on a #25 mesh screen. The fat-cellulosic coated pellets are then thoroughly mixed with the pellets which are not fat-cellulosic coated in a ratio of 9:1 to provide a uniform mixture.

Size No. 3 gelatin capsules are filled with the thus mixed pellets to provide a total dosage of 8 mg. of chlorprophenpyridamine maleate per capsule. Each cap- Each No. 3 capsule provides the desired body level of chlorprophenpyridamine maleate in about one-half hour. The coated pellets continue to provide suflicieut chlorprophenpyridamine maleate to maintain this desired body level for approximately ten hours.

Example V Percent w./v. Hydrogenated castor oil 8 Ethyl cellulose (15 cps.) 2

Chloroform, q.s. 100% volume.

The above solution is applied to medicated sugar pellets at room temperature, following the procedure of Example I, to a 6% increase in weight of the pellets. These pellets are filled directly into gelatin capsules with Chloroform, q.s. 100% volume.

The above solution is applied to medicated sugar pellets at room temperature, following the procedure of Example I, to a 6% increase in Weight of the pellets.

Example VII Percent w./v. Hydrogenated castor oil 9 Ethyl cellulose (15 cps.) 1 Chloroform, q.s. 100% volume.

The above solution is applied to medicated sugar pellets at room temperature, following the procedure of EX- ample I, to a 6% increase in weight of the pellets.

Example VIII Percent w./v. Glyceryl distearate 8 Ethyl cellulose (50 cps) 2 Ethyl alcohol, q.s. 100% volume.

This solution is applied to medicated sugar pellets at 60 C., following the procedure of Example I, to an 8% increase in weight of the pellets.

Example IX Percent w./v. Glyceryl tri-12-hydroxystearate 4 Glyceryl distearate 4 Ethyl cellulose (15 cps.) 2

Ethyl alcohol, q.s. 100% volume.

The above. solution is applied to medicated sugar pellets, at' 60 0., following. the procedure of Example II, to a increase in weight of the pellets.

The above solution is applied to medicated sugar pellets at' 60 C., following the procedure of Example I, to a 10% increase in weight of the pellets.

Example XI Percent w./v. Hydrogenated castor oil 12 Cellulose acetate butyrate 3 Chloroform, q.s. 100% volume.

The above solution is applied to medicated sugar pellets at room temperature, following the procedure of Example I, to a 6% increase in weight of the pellets.

Example XII Percent w./v. Hydrogenated castor oil 6.7 Cellulose acetate butyrate 3.3 Chloroform, q.s. 100% volume.

The above solution is applied to medicated sugar pellets at room temperature, following the procedure of EX- ample I, to a 6% increase in weight of the pellets.

Example XIII Percent w./v. Glyceryl distearate 12 Cellulose acetate butyrate 3 Ethyl alcohol, q.s. 100% volume.

The above solution is applied to medicated sugar pellets at 60 0., following the procedure of Example 11, to

a 10% increase in weight of the pellets.

Example XIV Percent w./v. Behenyl alcohol 5 Cellulose acetate butyrate 5 Ethyl alcohol: chloroform (3:1), q.s. 100% volume.

The above solution is applied to medicated sugar pellets at room temperature, following the procedure of Example I, to a 7% increase in weight of the pellets.

Example XV Percent w./v. Stearyl alcohol 5 Cellulose acetate butyrate 5 Ethyl alcohol: chloroform (3:1), q.s. 100% volume.

The above solution is applied to medicated sugar pellets at room temperature, following the procedure of Example I to a 9% increase in weight of the pellets.

Example XVI Percent w./v. IZ-hydroxystearyl alcohol 5 Cellulose acetate butyrate S Ethyl alcohol: chloroform (3:1), q.s. 100% volume.

The above solution is applied to medicated sugar pellets at room temperature, following the procedure of Example I, to a 9% increase in weight of the pellets.

Example XVII Percent w./v. Hydrogenated castor oil 5.6 Ethylene glycol monohydroxystearate 2.4 Cellulose acetate butyrate 2.0

7 Chloroform, q.s. volume.

The above solution is applied to medicated sugar pellets at :room: temperature, following the. procedure "oil Example II, to a 9% increase in weight of the pellets.

What is claimed is:

I l. A coating material for medicamentsto prolong the release of the medicament in the gastrointestinal tract which comprises an intimate mixture of a non-toxic, solid hydroxylated lipid material selected from the group consisting of a fatty alcohol having from 12 to 31 carbon atoms; a fatty ester of a glycol which has at least one free hydroxy group with a fatty acid of from 12 to 22 carbon atoms; a fatty ester of a glycerol which has at least one free hydroxy group with a fatty acid of from 12 to 22 carbon atoms; a solid ester of a fatty hydroxy acid with a lower aliphatic alcohol, the said ester having a total carbon content of 12 to 62 carbon atoms; a solid ester of a fatty polyhydric alcohol with a lower aliphatic acid, the said ester having a total carbon content of 12 to 62 carbon atoms; and a non-toxic, solid cellulose derivative represented by cellulose-R in which the R moiety is a member selected from the group consisting of an aliphatic alkyl group of from 1 to carbon atoms and an aliphatic acyl group of from 2 to 22 carbon atoms, the ratio by weight of said lipid material to said cellulosic material being from about 1:1 to about 9:1.

2. A coating material in accordance with claim 1 characterized in that the ratio by weight of said lipid ma terial to said cellulosic material is about 4: 1.

3. A coating material for medicaments to prolong the release of the medicament in the gastrointestinal tract which comprises an intimate mixture of hydrogenated castor oil and ethyl cellulose, the ratio by weight of hydrogenated castor oil to ethyl cellulose being from about 1:1 to about 9:1.

4. A coating material in accordance with claim 3 characterized in that the ratio by weight of hydrogenated castor oil to ethyl cellulose is about 4: 1.

5. A coating material for medicaments to prolong the release of the medicament in the gastrointestinal tract which comprises an intimate mixture of hydrogenated 5 characterized in that'the ratio .by weight of IZ-hydroxy- 'stearyl'alcohol to ethyl cellulose is about 4:1.

castor oil and cellulose acetate butyrate, the ratio by weight. of hydrogenated castor oil to cellulose acetate butyrate being from about 1: 1 to about 9: 1.

6. A coating material in accordance with claim 5 characterized in that the ratio by weight of hydrogenated castor oil to cellulose acetate butyrate is about 4:1.

7. A coating material for medicaments to prolong the release of the medicament in the gastrointestinal tract which comprises an intimate mixture of 12 hydroxystearyl alcohol and ethyl cellulose, the ratio by weight of IZ-hydroxystearyl alcohol to ethyl cellulose being from about 1:1 to about 9:1. v

'8, A coating material in accordance with claim 7 9. A coating material for medicaments to prolong the release of the medicament in the gastrointestinal tract which comprises an intimate mixture of l2-hydroxystearyl alcohol and cellulose acetate butyrate, the ratio by weight of IZ-hydroxystearyl alcohol to cellulose acetate butyrate being from about 1:1 to about 9:1.

10. A coating material in accordance with claim 9 characterized in that the ratio by weight of l2-hydroxystearyl alcohol to cellulose acetate butyrate is about 4:1.

11. A coating material for medicaments to prolong the release of the medicament in the gastrointestinal tract which comprises an intimate mixture of glyceryl tri-12- hydroxystearate and ethyl cellulose, the ratio by weight of glyceryl tri-lZ-hydroxystearate to ethyl cellulose being from about 1:1 to about 9:1.

12. A coating material in accordance with claim 11 characterized in that the ratio by weight of glyceryl tri- 12-hydroxystearate to ethyl cellulose is about 4: 1.

13. A pharmaceutical preparation providing a prolonged release of the contained medicament in the gastrointestinal tract which comprises a medicament protected by a coating comprising an intimate mixture of a nontoxic, solid hydroxylated lipid material selected from the group consisting of glyceryl tri-IZ-hydroxystearate, glyceryl di-12-hydroxystearate, glyceryl mono-IZ-hydroxystearate, behenyl alcohol, stearyl alcohol and 12-hydroxystearyl alcohol and a non-toxic, solid cellulose derivative selected from the group consisting of ethyl cellulose, methyl cellulose, propyl cellulose, cellulose acetate, cellulose acetate butyrate, cellulose propionate, cellulose caprate, cellulose acetate propionate and cellulose acetate stearate, the ratio by weight of said lipid material to said cellulosic material being from about 1:1 to about 9: 1.

14. A pharmaceutical preparation in accordance with claim 13 characterized in that the ratio by weight of said lipid material to said cellulosic material is about 4:1.

References Cited in the file of this patent UNITED STATES PATENTS 2,196,768 Hiatt Apr. 9, 1940 2,373,763 Kuever et al Apr. 17, 1945 2,540,979 Clymer et al. Feb. 6, 1951 2,798,024 Zapapas July 2, 1957 2,805,977 Robinson Sept. 10, 1957 2,881,085 Endicott Apr. 7, 1959 FOREIGN PATENTS 109,438 Australia Ian. 11, 1940 164,481 Australia Aug. 5, 1955 UNITED STATES PATENT OFFICE Certificate Patent- No. 2,921,883 Patented January 19, 1960 Davis R. Reese and Joseph V. Swintosky Application having been made jointly by Davis R. Reese and Joseph V. Swintosky, the inventors named in the patent above identified, and Smith Kline & French Laboratories, Philadelphia, Pennsylvania, a corporation of Pennsylvania, the assignee, for the issuance of a certificate under-the provisions of Title 35, Section 256 of the United States Code, deleting the name of the said Davis R. Reese from the patent as a joint inventor, and a showing and proof of facts satisfying the requirements of the said section having been submitted, it is this 19th day of February 1963, certified that the name of the said Davis R. Reese is hereby deleted from the said patent as a joint inventor with the said Joseph V. Swmtosky.

EDWIN L. REYNOLDS, First Assistant Uommz'ssz'oner of Patents.

5 UNITED STATES PATENT OFFICE i Certificate Patent No. 2,921,883 Patented January 19, 1960 D vis R. Reese and Joseph V. Swintosky Application having been made jointly by Davis R. Reese and Joseph V. Swintosky, the inventors named in the patent above identified, and Smith Kline & French Laboratories, Philadelphia, Pennsylvania, a corporation of Pennsylvania, the assignee, for the issuance of a certificate under-'the provisions of Title 35, Section 256 of the United States Code, deleting the name of the said Davis R. Reese from the patent as a joint inventor, and a showing and proof of facts satisfying the requirements of the said section having been submitted, it is this 19th day of February 1963, certified that the name of the said Davis R. Reese is hereby deleted from the said patent as a joint inventor with the said Joseph V. Swintosky.

[sEAL] EDWIN L. REYNOLDS, First Assistant Gammz'ssz'oner 0 Patents.

Claims (1)

1. A COATING MATERIAL FOR MEDICAMENTS TO PROLONG THE RELEASE OF THE MEDICAMENT IN THE GASTROINTESTINAL TRACT WHICH COMPRISES AN INTIMATE MIXTURE OF A NON-TOXIC, SOLID HYDROXYLATED LIPID MATERIAL SELECTED FROM THE GROUP CONSISTING OF A FATTY ALCOHOL HAVING FROM 12 TO 31 CARBON ATOMS, A FATTY ESTER OF A GLYCOL WHICH HAS AT LEAST ONE FREE HYDROXY GROYP WITH A FATTY ACID OF FROM 12 TO 22 CARBON ATOMS, A FATTY ESTER OF A GLYCEROL WHICH HAS AT LEAST ONE FREE HYDROXY GROUP WITH A FATTY ACID OF FROM 12 TO 22 CARBON ATOMS, A SOLID ESTER OF A FATTY HYDROXY ACID WITH A LOWER ALIPHATIC ALCOHOL, THE SAID ESTER HAVING A TOTAL CARBON CONTENT OF 12 TO 62 CARBON ATOMS, A SOLID ESTER OF A FATTY POLYHYDRIC ALCOHOL WITH A LOWER ALIPHATIC ACID, THE SAID ESTER HAVING A TOTAL CARBON CONTENT OF 12 TO 62 CARBON ATOMS, AND A NON-TOXIC, SOLID CELLULOSE DERIVATIVE REPRESENTED BY CELLULOSE-R IN WHICH THE R MOIETY, IS A MEMBER SELECTED FROM THE GROUP CONSISTING OF AN ALIPHATIC ALKYL GROUP OF FROM 1 TO 5 CARBON ATOMS AND AN ALIPHATIC ACYL GROUP OF FROM 2 TO 22 CARBON ATOMS, THE RATIO BY WEIGHT OF SAID LIPID MATERIAL TO SAID CELLULOSIC MATERIAL BEING FROM ABOUT 1:1 TO ABOUT 9:1.