DETERMINATION OF U-85575 IN RAT SERUM BY SOLID-PHASE EXTRACTION AND HIGH-PERFORMANCE LIQUID-CHROMATOGRAPHY

Solid phase extraction and liquid chromatographic methods are described for the isolation and quantitataon of U-85575 from rat serum. The assay utilizes a simple extraction of U-85575 from serum with phenyl solid phase columns. The extracts were chromatographed on a CN reverse-phase column using a mobile phase of acetonitrile-water (32:68, v/v) containing 0.2% triethylamine (pH 6.5 +/- 0.05). The method has a limit of quantitation of 50 ng/ml of U-85575 in serum and is linear in the range of 0.05 to 20 mug/ml. The precision and accuracy of this method was proved to be <10% at the three concentrations evaluated. The method was demonstrated to be suitable to determine U-85575 concentrations in rat serum samples collected from a preliminary 15-day toxicity study.