Patent GB-643853-A (GB)
Title: Medicinal capsules and process of manufacture
IPC: A61K9/48
Filed: 1947-01-03
Abstract: A thermo-gelled film of a water-soluble methyl cellulose having a methoxyl content of 25 to 35 per cent and an intrinsic viscosity (based on a 2 per cent solution in distilled water at 20 DEG  C.) of 7 to 15 centipoises, is used in the formation of a telescoping medicinal capsule.  A methoxy content of 30 per cent and a viscosity of 9 centipoises is preferred.  Flexibility is improved and capsules suitable for enclosing hygroscopic medicaments are made by incorporating plasticizers such as invert sugar, sorbitol, mannitol, sucrose, dextrose, monacetin, lactose, triethyl phosphate, glycerol; monoethers of glycerol such as glycerol a -methyl ethers, a - and b -glucoheptonic acid and/or their lactones and lower alkyl and glycol esters, glucono g -lactone, g -valerolactone; a -amino acids, e.g. glycine, ethyl glycinate; amines such as monoethanolamine and triethanolamine; glycols such as propylene glycol, triethylene glycol, 2-ethyl-1,3-hexanediol, 1,3-butylene glycol; glucosides such as a -methyl glucoside; acetopropanol, amides such as acetamide and propionamide.  Further there may be present: (a) electrolytes, e.g. benzene sulphonic acid, toluene sulphonic acid and citric acid; (b) colouring materials such as edible dyes of animal or vegetable origin, e.g. carmine, cudbear and caramel, or synthetic dyes, e.g. amaranth, brilliant blue F.C.F., eosin, erythrosine, guinea green certified, orange I, ponceau 3R, sunset yellow F.C.F., and tartrazine; (c) substances rendering the capsules opaque, e.g. charcoal and titanium dioxide; (d) gums, e.g. acacia; (e) wetting agents, e.g. sodium dioctyl sulphosuccinate; (f) non-thermogelling cellulose derivatives, e.g. water-soluble hydroxy ethyl cellulose; (g) Carbowax-a polyethylene glycol. The capsules are formed by dipping highly-polished, stainless steel pins, maintained at, say, 65 DEG  C., into a bubble-free aqueous solution of methyl cellulose of suitable viscosity, preferably maintained at 18 DEG  C., and gelling should occur within 35 seconds of such contact.  The temperature of the pins may be varied over, say, 40 DEG  to 80 DEG  C., depending upon the size of the capsules and the viscosity of the methyl cellulose employed.  Before dipping, the pins are lubricated with, e.g. a mixture of equal parts of anhydrous lanolin and soft soap containing 0.1 per cent by weight of chromium trioxide.  After dipping, the coated pins are rotated to facilitate even coating and dried in a kiln through which a current of air is passed, the temperature being maintained at 40 DEG  C. for 30 minutes and then slowly raised to 60 DEG  C. over a further 15 minutes, such drying preventing brittleness.  Infra-red radiation may be used in the drying operation.  The Specification as open to inspection under Sect. 91 disclosed that any water-soluble thermogelling etherified cellulose derivative may be used, e.g. ethyl substituted ethers and p methylated cellulose ethers of glycollic acid.  This subject-matter does not appear in the Specification as accepted.ALSO:A telescoping medicinal capsule is formed of a thermo-gelled film of a water-soluble methyl cellulose having a methoxy content of 25 to 35 per cent and an intrinsic viscosity (2 per cent solution in distilled water at 20 DEG C) of 7 to 15 centipoises.  A methoxy content of 30 per cent and viscosity of 9 centipoises is preferred.  Flexibility is improved and capsules suitable for enclosing hydroscopic medicaments are made by incorporating plasticizers such as invert sugar, sorbitol, mannitol, sucrose, dextrose, lactose, monacitin, triethyl phosphate, glycerol; monoethers of glycerol such as glycerol a  - methyl ether; a - and b - gluco heptonic acid and/or their lactones and lower alkyl and glycol esters, glucono d -lactone, n -valerolactone; a -amino acids, e.g. glycine, ethyl glycinate; amines such as mono- and tri-ethanolamines; glycols such as propylene glycol, triethylene glycol, 2-ethyl-1,3 hexane diol, 1,3-butylene glycol; glycosides such as a -methyl glucoside, aceto-propanol; amides such as acetamide and propionamide.  The capsule wall material may also contain (a) electrolytes, e.g. benzene sulphonic acid, toluene sulphonic acid and citric acid; (b) colouring materials such as edible of animal or vegetable origin, e.g. carmine, cudbear and caramel or synthetic dyes, e.g. amaranth, brilliant blue F.C.F., losin, erythrosine, guinea green certified, orange I, porceau 3R, sunset yellow F.C.F. and tartrazine; (c) substances rendering the capsule opaque, e.g. charcoal and titanium dioxide; (d) gums, e.g. acacia; (e) wetting agents, e.g. sodium dioctyl sulphosuccinate; (f) non-thermo-gelling cellulose derivatives, e.g. water soluble hydroxyethyl cellulose; (g) carbowax-a polyethylene glycol.  The capsules are formed by dipping highly polished, stainless steel pins, maintained at say 65 DEG C, into a bubble-free aqueous solution of methyl cellulose of suitable viscosity preferably maintained at 18 DEG C (see Group IVa).  The Specification as open to inspection under Sect. 91 comprises capsules having as an essential ingredient any water-soluble thermo-gelling etherified cellulose derivative, e.g. ethyl substituted ethers and methylated cellulose ethers of glycollic acid.  This subject-matter does not appear in the Specification as accepted.