HIGH-PERFORMANCE LIQUID-CHROMATOGRAPHIC ASSAY FOR CI-1004, A DUAL-INHIBITOR ANTIINFLAMMATORY AGENT, IN RAT, RABBIT, DOG, MONKEY AND HUMAN PLASMA

CI-1004 and PD 138389 (internal standard, I.S.), were isolated from ra t, rabbit, dog, monkey and human plasma by solid-phase extraction with Bond-Elut C18 cartridges. Liquid chromatographic separation was achie ved isocratically on a Zorbax Rx-C8 analytical column (250 mmX4.6 mm I .D). The mobile phase consisted of acetonitrile-20 mM ammonium acetate (65:35, v/v), (pH 4.0). Column temperature was either 40 degrees C (h uman assay) or 45 degrees C and column effluent was monitored spectrop hotometrically at 360 nm. Specificity, chromatographic performance par ameters, system repeatability, recovery from matrix, linearity, precis ion, accuracy and stability were evaluated. Mean retention times (+/-S .D.) of CI-1004 and I.S. were 7.8+/-0.1 and 10.9+/-0.2 at 40 degrees C and 7.7+/-0.2 min and 10.7+/-0.2 min at 45 degrees C. No interfering peaks were observed at the retention time of CI-1004 throughout the va lidation process. Peak height ratios were proportional to CI-1004 over the concentration range of 7.5-5000 ng/ml in rat, rabbit and monkey p lasma and 2.5-5000 ng/ml in dog and human plasma. Recovery of low, med ium and high standards of CI-1004 ranged from 82.8-107% from all anima l species and recovery of I.S. from rat, rabbit, dog and monkey plasma ranged from 77.5-82.0% and from human plasma was 111%. Assay precisio n for CI-1004 based on quality control samples was less than or equal to 8.5% C.V. with an accuracy (percentage relative error) of +/-4.7% f or all species. Minimum quantitation limit of CI-1004 was 7.5 ng/ml fo r 0.2 ml rat, rabbit and monkey plasma samples and 2.5 ng/ml for 0.5 m l dog and human plasma samples. The method is suitable for studying th e preclinical and clinical pharmacokinetics of CI-1004;. (C) 1997 Else vier Science B.V.