DESIGN & DEVELOPMENT OF DILTIAZEM HCL FLOATING TABLET

The aim of this study was to develop floating matrix tablet of Diltiazem HCl. Diltiazem HCl, a benzodiazepine derivative with vasodilating action due to its antagonism of the actions of the calcium ion in membrane functions. The tablets were prepared by direct compression method using HPMC K4M, HPMC K15M and HP MC K100M polymer and NaHCO3 as gas generating agent. Simplex Lattice design was used for optimization. The concentrations of HPMC K4M(Xi), HPMC K15M(X2) and HPMC K100M(X3) were selected as the independent variables. The amount of the drug released at 2 hr (Q2), 6 hr (Q6) and 10 hr (Q10), floating lag time, diffusion coefficient (n) and rate constant (k) were selected as the dependent variables. Tablets were evaluated for in vitro dissolution, floating lag time, friability, hardness, drug content, and weight variation. Dissolution data were fitted to various models to ascertain kinetic of drug release. The drug release from the matrix tablet best fitted in korsemeyer's peppas model showing anamolous release i.e both diffusion and dissolution controlled release. Optimized formulation (D5) showed good similarity with theoretical profile of Diltiazem HCl. Different grades of HPMC had profound effect on both floating lag time and release rate, this is because of difference in viscosity of various grades of HPMC. Increase in amount and grade of HPMC from K4M to K100M decreased floating lag time as well as release rate and vice-versa.