Acid resistant capsules
The present invention relates to new acid resistant hard pharmaceutical capsules, a process for their manufacture and use of such capsules particularly but not exclusively for oral administration of pharmaceuticals, veterinary products, food and dietary supplements to humans or animals. The capsules of the invention are obtained by aqueous compositions comprising a water soluble film forming polymer and gellan gum in a mutual weight ratio of 4 to 15 weight parts of gellan gum for 100 weight parts of film forming polymer.
1. An acid resistant hard pharmaceutical capsule shell consisting essentially of gellan gum, HPMC, and optionally at least one additive selected from the group consisting of inert, non-toxic pharmaceutical grade or food grade pigments, plasticizers, surfactants, and flavouring agents, wherein the weight ratio of gellan gum to HPMC ranges from 4.5 to 15 parts by weight of gellan gum per 100 parts by weight of HPMC, wherein said hard capsule shell exhibits resistance to leakage of at least 1 hour at pH 1.2 in a USP-30 simulated gastric fluid, and further wherein the capsule shell is filled with at least one substance selected from the group consisting of acid-instable substances and substances associated with gastric side effects in humans and/or animals.
2. The hard capsule shell according to claim 1 further wherein the capsule shell has a moisture content ranging from about 2% to about 16% over the total weight of the shell.
3. A dip-molding process for the manufacture of an acid resistant hard pharmaceutical capsule shell according to claim 1 , said process comprising:
dipping pins into an aqueous composition according to claim 1 ;
withdrawing the dipping pins from the aqueous composition; and
drying the composition adhered on the dipping pins so as to obtain a shell.
4. A method of administering to a patient in need the acid resistant hard pharmaceutical capsule shell according to claim 1 , wherein the acid resistant hard pharmaceutical capsule contains at least one substance selected from the group consisting of acid-instable substances and substances associated with gastric side effects.