CONTROLLED RELEASE COMPOSITION FOR ACTIVE SUBSTANCES INTO AN AQUEOUS MEDIUM

摘要

A composition for delaying release of an active component into an aqueous fluid is taught which includes a capsule that swells in the presence of an aqueous fluid allowing moisture to enter the capsule into contact with a capsule decomposing agent activated by the entering moisture such that the agent decomposes the capsule sufficiently to release the active agent at a predetermined delayed time after the capsule contacts the aqueous fluid. A preferred capsule composition is gelatin and decomposing agents are a proteolytic enzyme or a salt that affects the osmotic gradient of the system. The controlled release composition of the invention is preferably utilized in a soft contact lens disinfecting system wherein a solution of hydrogen peroxide disinfects the lenses followed by neutralization of residual hydrogen peroxide wherein release of the neutralizing agent is delayed by means of the capsule proteolytic enzyme or salt composition.