A novel nasal delivery system of a chinese traditional medicine,Radix Bupleuri, based on the concept of ion-activated in situ gel

The purpose of this study was to develop a nasal in situ gel system forRadix Bupleuri employing gellan gum as a polymer.Radix Bupleuri in situ gel containing 0.2 mL essential oil extracted from 450 gRadix Bupleuri, proper solubilizing agents and gellan gum (0.5% w/v) was prepared and characterized. The antipyretic effect produced by in situ gel formulation was investigated in fevered rabbits and compared to an intranasal solution. The resulting in situ gel was a clear and light-yellow liquid, with viscosity of 346 mPa.s and caproic acid content of 1.31± 0.01 mg/mL Intranasal administration of this preparation to fevered rabbits decreased body temperature markedly (1.1°C at the doses of oil from 1.5 gBupleuri/body) and the effect could last for 20-30 h. The results suggest thatRadix Bupleuri in situ gel can be greater effective than the solution in the treatment of fever.