Preparation of ranitidine hydrochloride microcapsules and its biphasic release kinetics

Abstract

The emulsion–solvent–evaporation technique has been adopted in microencapsulation of ranitidine HCl, an antiulcer drug using coating polymer Eudragit RS-100. The biphasic release kinetics of ranitidine HCl has been evaluated. A matrix mechanism predominates in the early phase of the release of drug from the micro-capsules followed by a first-order release kinetics in the second phase. Drug release from the microcapsules was determined in the light of different kinetic models like zero-order, Higuchi matrix, first-order, and Baker-Lonsdale. These have been characterized by differential rate treatment and correlation coefficient analysis. In vitro dissolution study has been carried out to evaluate diffusion coefficient (D_α) and diffusivity rate constant (k_bl) with the help of the Baker-Lonsdale model for the first phase. Similarly the first-order re-lease rate constant (k₁) and the permeability constant (P_i) for the first-order mechanism during the second phase of release have been evaluated.