Bhanudas S. Kuchekar

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.

Oxalis corniculata Linn. (Oxalidaceae) is one of the important medicinal plants used traditionally for the treatment of fever, pain and inflammation. The present study was aimed to screen antipyretic activity of petroleum ether, chloroform, ethyl acetate, methanol extracts and β-sitosterol isolated from petroleum ether extract of Oxalis corniculata Linn. The leaves of Oxalis corniculata Linn. was used for successive extraction with increasing polarity solvents. Petroleum ether extract was selected for activity-guided fractionation to isolate β-sitosterol due to its better efficacy than other extracts. Antipyretic activity was done by yeast induced pyrexia method. All the extracts were screened at the dose of 100 mg/kg, i.p. and isolated β-sitosterol was screened at the dose of 10 and 20 mg/kg. The result showed that after five hour of petroleum ether extract (100 mg/kg) administration significant inhibition of pyrexia up to 89.5% was observed. Isolated β-sitosterol 10 and 20 mg/kg, i.p. showed promising antipyretic activity with inhibition of pyrexia by 91.23 and 94.41% respectively. Results are compared with standard drug paracetamol (50 mg/kg i.p.). Thus the present pharmacological screening provides support for the folklore claim of antipyretic activity of Oxalis corniculata Linn.