Rapid and selective UV spectrophotometric and RP-HPLC methods for dissolution studies of oxybutynin immediate-release and controlled-release formulations.

摘要

A new UV spectrophotometric method and a reversed-phase HPLC method were developed for quantitative evaluation of oxybutynin hydrochloride (OXB) formulations. Determination of OXB by UV spectroscopic method was based on complexation of OXB with picric acid to form picrate, which was extracted to chloroform. The picrate complex showed quantifiable absorbance at 344nm. Chromatography was carried out at 25 degrees C on a 4.6mm x 250mm 5mum cyano column that contained USP packing L10 with water:methanol:acetonitrile::48:12:40 (v/v), as mobile phase. UV detector was set at 203nm. Both methods were found to be selective, linear, accurate and precise in the specified ranges. The LOD and LOQ of HPLC method were 0.5 and 1.65mug/ml, respectively. Intra-day and inter-day variability for both methods were <2% RSD. These methods were successfully used for quantification of OXB in drug-release studies from immediate-release tablets and controlled-release (CR) formulations.