Controlled release of diltiazem hydrochloride

A new type of complex reservoir-matrix system for the controlled delivery of diltiazem hydrochloride was developed. This capsule-type device was designed for oral administration to humans and/or animals. It contained (i) an appropriate amount of the drug in a compartment ; (ii) a swelling-controlled membrane which was prepared by mixing polymeric materials with another appropriate amount of the drug ; and (iii) a water-soluble gelatin capsule as container. The swelling-controlled membranes were prepared from poly(2-hydroxyethyl methacrylate) hydrogels. The effect of pH on the swelling of the hydrogels was studied. In-vitro dissolution testing was carried out to evaluate the release of the drug using a continuous-flow method. Zero-order release kinetics was obtained over a period of 12 h.