Development and Evaluation of Gastroretentive Floating Tablets of Neem Leaf Extract Using Psyllium Husk

Gastro retentive systems can remain in the gastric region for several hours and hence prolongs the gastric residence time of drugs and improve the bioavailability. The aim of this project was to develop sustained release floating matrix tablet for hydroalcoholic extract of neem leaves using psyllium husk as release controlling polymer along with synthetic polymer HPMC K100 M and sodium bicarbonate as gas generating agent. The tablets were prepared by direct compression method. Seven different formulations A1 to A7 were prepared by varying the concentration of psyllium husk, HPMC K100 M and sodium bicarbonate. Tablets were evaluated for pre and post compression parameters like tablet thickness, hardness, weight variation, drug content, friability, floating lag time and in vitro drug release. Results for angle repose, swelling index, weight variation, drug content, thickness, hardness, % friability for all the formulations were found to be in acceptable limit. In vitro drug release was observed for 12 hours and all the tablet formulations followed zero-order kinetics and/ or Korsemeyer-Peppas model in drug release. The formulations were optimized on the basis of buoyancy time and in vitro drug release. The optimized formulation was found to be A4 with 98.77% in vitro drug release in 12 h and 212 seconds buoyancy time. The BaSO4 tagged formulation, similar to formulation A4 was tested in in vivo gastric retention study in rabbits. It was observed that formulation kept floating in the stomach region till 10 hours. Formulations containing combination of psyllium husk and HPMC K100M with sodium bicarbonate as gas generating agent can be a promising way for formulating gastroretentive drug delivery systems.