| 摘要 |
A composition for controlled delivery of at least one active substance into an aqueous medium by erosion at a preprogrammed rate of at least one surface of the composition, the composition comprising a matrix which is erodible in the aqueous medium in which the composition is to be used and which allows substantially no diffusion of water into the composition beyond any exposed surface layers of the matrix, the matrix comprising at least one substantially water soluble crystalline polymer, e.g. a polyethylene glycol, with at least one water-dispersible or water-soluble surface active agent, e.g. a non-ionic emulsifier, dispersed therein, at least one release modifier, e.g. an enteric coating material, that functions to regulate erosion of the matrix within a pH range of from about 2 to about 7, and at least one active substance. The composition provides controlled, e.g. substantially zero order, release in both the stomach and the intestines despite different conditions of pH, agitation and absorption.
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