ABSTRACT
The problems of frequent administration and variable low bioavailability after oral administration of conventional dosage forms of diltiazem can be attenuated by designing it in the form of microcapsules which would facilitate intimate contact with the absorption surface and thereby improve and enhance the bioavailability. Diltiazem-loaded microcapsules were successfully prepared by ionotropic gelation technique employing Sodium carboxy methylcellulose, Xanthan gum as rate controlling polymers and Aluminium chloride as cross linking agent. Microcapsules obtained were discrete, spherical, free flowing and showed a maximum encapsulation efficiency of 91.20 ± 0.08%. Particle size of the microcapsules was found to be in the range of 1009 – 1311 μm. Interaction studies performed using FTIR spectroscopy revealed that there were no drug and polymer interactions. The drug remained dispersed in the polymer matrix in amorphous state, which was confirmed by X-ray diffraction analysis. The in vitro drug release follows matrix-diffusion controlled release and the release mechanism was non-Fickian type controlled by swelling and relaxation of polymer. There was no significant change in drug content and cumulative drug release of drug-loaded microcapsules stored at different storage condition after 90 days. From the study, it was concluded that diltiazem loaded microcapsules could be successfully prepared by ionotropic gelation technique with high entrapment efficiency and prolonged release characteristics.