High-performance liquid chromatographic analysis of a selective cyclooxygenase-1 inhibitor SC-560 in rat serum: application to pharmacokinetic studies.

A method of analysis of SC-560 (5-(4-chlorophenyl)-1-(4-methoxyphenyl)-3-(trifluoromethyl)-1H-pyrazole) in biological fluids is necessary to study the kinetics of in vitro and in vivo metabolism. A simple high-performance liquid chromatographic method was developed for simultaneous determination of SC-560 and other products of metabolism in rat serum. Serum (0.1 ml) was precipitated with acetonitrile after addition of the internal standard, testosterone 17-propionate. Separation was achieved on a C(8) column with UV-detection at 240 nm. The calibration curve was linear ranging from 0.02 to 100 microg/ml. The mean recovery was >86.7%. Precision of the assay was <10% (R.S.D.%), and was within 15% at the limit of quantitation (20 ng/ml). Bias of the assay was lower than 15.5%. The limit of detection was 10 ng/ml for a 0.1 ml sample. The assay was applied successfully to the in vivo kinetic study of SC-560 in rats.