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 (Dα) and diffusivity rate constant (kbl) 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 (Pi) for the first-order mechanism during the second phase of release have been evaluated.