Formulation and Evaluation of Floating Matrix Tablets of Acyclovir using 3² Factorial Design

Floating Drug Delivery Systems (FDDS) have a bulk density lower than gastric fluids and thus remain buoyant in the stomach for a prolonged period of time, without affecting the gastric emptying rate. While the system is floating on the gastric contents, the drug is released slowly at a desired rate from the system. These floating tablets mainly prepared for reduction of lag time and release the drug up to 12 hours and may also increase the bioavailability of the drugs by utilizing the drug to full extent avoiding unnecessary frequency of dosing. The study included formulation of floating tablets using polymers like Hydroxy propyl methyl cellulose K15M, PVP K30, Sodium bicarbonate, Xanthan-Gum, Guar-gum and microcrystalline cellulose as matrix forming agents. The tablets were directly compressed using Lab Press multi station rotary punching machine. FTIR and DSC-TGA studies conformed that there was no incompatibility between the polymers and the drug. Tablet preformulation parameters were within the Pharmacopoeias limit. Tablet showed zero lag time, continuance of buoyancy for >12 h. In vivo X-ray studies depicted that tablets continued to float in the GIT for 12 h. The in vitro drug release pattern of Acyclovir floating tablets was fitted to different kinetic models which showed highest regression for zero order kinetics with Koresmeyer-peppasand most of the formulations followed Nonfickian diffusion.