Formulation and optimisation of lamivudine-loaded Eudragit® S 100 polymer-coated pectin microspheres for colon-specific delivery.

This investigation is to find a prolonged or delayed drug release system, exclusively for the treatment of hepatitis-B to reduce the side effects, which arise when conventional solid dose forms are administered. To pursue this goal, lamivudine-loaded Eudragit-coated pectin microspheres have been formulated employing water/oil (W/O) emulsion evaporation strategy. The formulation was optimised using a 34 factorial design. A drug to polymer ratio of 1:2, the surfactant of 1 ml, the volume of 50 ml of processing medium with a stirring speed of 2500 rpm were found to be the optimal parameters to obtain the lamivudine-loaded Eudragit-coated pectin microspheres formulation with a high drug entrapment efficiency of 89.44% ± 1.44%. The in vitro release kinetics of lamivudine was a suitable fit to the Higuchi model, indicating a diffusion-controlled release with anomalous transport. The obtained microspheres were then subjected to different characterisation studies, including scanning electron microscopy (SEM), Fourier transform infrared spectroscopy (FTIR), differential scanning calorimetry (DSC), and X-ray diffraction (XRD). The results of this study clearly indicate that Eudragit-coated pectin microspheres could be the promising controlled release carriers for colon-specific delivery of lamivudine in the presence of rat cecal content.