Patent GB-743014-A (GB)
Title: Improvements in and relating to enteric capsules for medicaments
IPC: B29C41/14
Filed: 1953-05-01
Abstract: An alkaline acqueous solution of a phthalic acid ester of either cellulose, cellulose ethyl ether containing 26-38 per cent by weight of ethoxyl groups and 6-35 per cent of phthalyl groups, or cellulose acetate containing not more than 23 per cent of acetyl groups and not less than 10 per cent of phthalyl groups, is formed into an enteric capsule shell.  A shell forming element may be dipped into the solution and the skin which is formed thereon is solidified and dried.  A medicament is then placed inside the shell and the shell is sealed.  Alternatively, a medicament may be coated with a film of the solution which is then set and dried. A medicament and the alkaline aqueous solution of the cellulose ester may be co-extruded at low temperature to form a succession of globules of medicament surrounded by the cellulose ester.  The globules are allowed to fall into warm water which sets the composition and the gelled spheres may be dried on a vibrating table in a current of warm air.  The cellulose ester solution may be allowed to flow from a tube and upon the formation of each drop thereof, medicament may be injected into the globule, which is then dipped into dilute acid and set.  If desired the globules may first be formed or shaped in a non-solvent bath, prior to setting in the acid solution, e.g. in benzene with ethylene chloride or other chlorinated hydrocarbon added to adjust the density of the bath to that of the globules.  The alkaline aqueous solution may be obtained by dissolving the alkali metal salt or the ammonium salt of the cellulose ester in water, or by dissolving the acid form of the cellulose ester in water having a pH of at least 7.5 such as imparted by the addition of sodium or potassium carbonate, bicarbonate, or borate, or by the addition of ammonia, or a basic amine.  A plasticizer such as glycerin, ethylene glycol, or triacetin may be incorporated in the solution or applied to the formed capsule shell. The shell-forming element or mould may be a polished steel mandrel or a round-tipped rod which dips into the cellulose ester solution and can be rotated to obtain an even distribution of the coating.  The complete enteric capsule containing the desired medicament may be formed by putting together two of the half capsule shells either or both of which may contain the medicament.  The medicament may be ferrous sulphate, aspirin, bile salts, pancreatin, gentian violet, ammonium chloride, mandelic acid, or barium sulphate. Specifications 526,276 and 638,284 are referred to.ALSO:An enteric capsule shell is formed from an alkaline aqueous solution of a phthalic acid ester of either cellulose, cellulose ethyl ether containing 26-38 per cent by weight of ethoxyl groups and 6-35 per cent of phthalyl groups, or cellulose acetate containing not more than 23 per cent of acetyl groups and not less than 10 per cent of phthalyl groups.  A shell-forming element may be dipped into the solution, the skin which is formed thereon being solidified and dried; a medicament is placed inside the shell so formed and the shell is sealed.  Alternatively, a medicament may be coated with a film of the solution which is then set and dried.  A medicament and the alkaline aqueous solution of the cellulose ester may be co-extruded at low temperature to form a succession of globules of medicament surrounded by the cellulose ester.  The globules are allowed to fall into warm water and the gelled spheres may be dried on a vibrating table in a current of warm air.  The cellulose ester solution may be allowed to flow from a tube, and upon the formation of each drop thereof, medicament may be injected into the globule, which is then dipped into dilute acid and set.  If desired, the globules may first be formed or shaped in a non-solvent bath, prior to setting in the acid solution, e.g. in benzene with ethylene chloride or other chlorinated hydrocarbon added to adjust the density of the bath to that of the globules. The shell-forming element or mould may be a polished steel mandrel or a round-tipped rod which dips into the cellulose ester solution and can be rotated to obtain an even distribution of the coating. The complete enteric capsule containing the desired medicament may be formed by putting together two of the half-capsule shells either or both of which may contain the medicament. Specifications 526,276, [Group IV], and 638,284 are referred to.