CA2007181C — Sustained release pharmaceutical composition

USPTO Abstract

A sustained release pharmaceutical pellet composition comprises a core element of an active ingredient of high solubility and a coating for the core element. The coating is partially soluble at a highly acidic pH to provide a slow rate of release of the active ingredient. The active ingredient may be a variety of highly soluble medicines. The coating includes at least one insoluble matrix polymer selected from the group consisting of acrylic ester polymers, methacrylic ester polymers and mixtures thereof; at least one enteric polymer selected from the group consisting of cellulose acetate phthalate, hydroxypropyl methyl-cellulose phthalate, polyvinyl acetate phthalate, methacylic acid copolymer, hydroxypropyl methylcellulose acetate succinate, shellac, cellulose acetate trimellitate and mixtures thereof and at least one partially acid soluble component selected from polyvinylpyrrolidone, hydroxypropyl cellulose, hydroxypropyl methylcellulose, polyethylene glycol, polyvinyl alcohol and monomers therefor and mixtures thereof. This coating composition is particularly suited in providing sustained release of the active ingredient and maintaining the desired effective level in the blood stream.