Thermal Treatment of Beads with Wax for Controlled Release

Abstract

Beads prepared by extruder/marumerizer technology were formulated with water soluble drugs, microcrystalline cellulose and several waxy materials. The waxes (10 to 50% by weight) were included in an effort to slow drug release. Subsequent thermal treatment of these beads was applied. Beads were processed to determine the effect of varying wax level, excipient, active drug, and effect of heat treatment. In-vitro drug release profiles were evaluated for the untreated and thermal treated beads. In general, the simple incorporation of wax into the granulation did not provide the desired controlled release dissolution profile. Thermal treatment of the finished beads, however, resulted in products which behaved in a different manner during dissolution testing and in general provided slower release. Drug release was found to vary with the type and level of wax, drug, excipient, and the thermal treatment.