Macro- and micromethods for high-performance liquid chromatographic analysis of oxaprozin in plasma

A high-performance liquid chromatographic method for the analysis of oxaprozin in the presence of ketoprofen (the internal standard) was developed. Sample preparation involved macro- and microextraction procedures. An octadecylsilane reversed-phase system with an acetonitrile-phosphate buffer (pH 3.9) mobile phase was used to separate the compounds from the extracted plasma components and the oxaprozin metabolites. Linear UV detector response over a wide concentration range resulted in rapid and reproducible quantitation.