ABSTRACT:
The main objective of the present study was to improve bioavailability of diltiazem hydrochloride and to decrease the frequency of dosage form administration by increasing the encapsulation efficiency of the drug, residence time of the dosage form at the site of absorption and sustained release of the drug from the delivery system. Diltiazem-loaded mucoadhesive microspheres were prepared by emulsification-internal gelation technique. The mucoadhesive microspheres were prepared by using sodium alginate alone and in combination with HPMC K4M and carbopol 934P. The size distribution of microsphere batches generally ranged from 778.59 to 924.28 µm. The in vitro wash-off test indicated that the microspheres had good mucoadhesive properties. The wash-off was faster at simulated intestinal fluid (phosphate buffer, pH 7.4) than that at simulated gastric fluid (0.1 M HCl, pH 1.2). The scanning electron microscopy, X-ray diffractometry, Differential scanning calorimetry and in vitro dissolution studies were performed to characterize the microspheres. The in vitro drug release mechanism was non-fickian type controlled by swelling and relaxation of polymer.