Diltiazem Hydrochloride Floating Matrix Tablet: Formulation and in vitro-in vivo Evaluation

Background: Diltiazem hydrochloride is a calcium channel-blocker with a plasma elimination half-life of 4.4 ± 1.3 h and has a narrow absorption window. So, this work aimed to prepare a gastro-retentive floating matrix tablet. Methods: The direct compression method was used to manufacture tablets. 3² factorial design was applied for optimization, taking Hydroxypropyl Methylcellulose K100M (HPMC K 100M) and the amount of sodium bicarbonate as independent factors and cumulative percentage release at 1 h, at 6 h, and at 12 h and floating lag time as dependent variables. Results: The high amount of HPMC K100M and sodium bicarbonate shows good results. The optimized preparation was evaluated for differential scanning calorimetry, in-vivo gastric retention in male albino rabbits, kinetic modeling, and stability study. An in vivo study revealed gastric retention of tablets up to 6 h in healthy male Albino rabbits. The stability study indicated no significant change in the buoyancy and release profiles of the drug. Conclusion: From this study, it can be concluded that the gastro-retentive diltiazem hydrochloride floating matrix tablet was successfully prepared and retained inside the rabbit stomach for up to 6 h and was stable under accelerated stability study.