ABSTRACT:
Floating microspheres of Diltiazem Hydrochloride were prepared by Ionotropic Gelation Technique using sodium alginate. By varying drug to polymer ratio six different formulations comprising combination of Hydroxy Propyl Methyl Cellulose K-100M with Eudragit RS-100 and Hydroxy Propyl Methyl Cellulose K-100M alone were prepared with an objective to prolong drug release by increasing gastric residence time to increase its bioavailability. Sodium bicarbonate and calcium chloride were used as gas generating agent and cross-linking agent respectively. The formulations were evaluated for micromeritic study, drug entrapment efficiency, floating ability, in-vitro drug release and prediction of its pattern and for drug-excepients compatibility. The prepared microspheres were faint brown, discrete, spherical, compact and free flowing with size distribution between 150 to 250µm. The drug entrapment, loading and encapsulation efficiency were found in the range of 39.25% to 76.06%, 26.34% to 63.27% and 24.98% to 96.47% respectively. Floating time for all the formulations was ? 8 h. Release was found to be affected by composition and concentration of retardants. The drug release pattern followed a Higuchi mechanism. Drug release from the formulation prepared with Hydroxy Propyl Methyl Cellulose K-100M: Drug as 1.5:1 was found to be optimum (87% after 12 h). XR-PD study shows decreased crystallinity of drug in the formulation. Drug-polymer interactions were not seen as evidenced by FT-IR. From the study it can be concluded that Diltiazem hydrochloride can be successfully prepared by ionotropic gelation technique with high drug entrapment and efficiency with prolong release characteristics thereby improving bioavailability and patient compliance.