Determination of a new thymidine phosphorylase inhibitor, TPI, in dog and rat plasma by reversed-phase ion-pair high-performance liquid chromatography

A high-performance liquid chromatographic method for the determination of a new thymidine phosphorylase inhibitor, TPI, in dog and rat plasma is descr ibed. TPI was isolated from biological samples by solid-phase extraction on Bond Elut PRS columns. Chromatographic separation was achieved on a C-18 c olumn using a mobile phase consisting of acetonitrile-10 mM acetate buffer (pH 4.3) including hexanesulfonate, with UV detection at 276 nm. This metho d has been validated across the range of 50-50 000 ng/ml using a 0.1-ml pla sma volume. The mean recoveries from spiked plasma were 93% for dog and 94% for rat, respectively. The accuracy, precision and specificity of the meth od were demonstrated to be acceptable, and it was applied to the toxicokine tic study of TPI in rats. (C) 2001 Elsevier Science B.V. All rights reserve d.