Validated HPLC method for determination of PAT-5A, an insulin sensitizing agent, in rat plasma

A high performance liquid chromatographic method for the determination of P AT-SA (a potent insulin sensitizer) using DRF-2095 (a thiazolidinedione) as internal standard (I.S.) is described. A 1:1 v/v ethylacetate and dichloro methane solvent mixture was used for extraction of PAT-SA from plasma: A Kr omasil KR100-5C18-250A, 5 mu m, 4.6 x 250 mm SS column was used for the ana lysis. Mobile phase consisting of sodium dihydrogen phosphate (pH 4.0, 0.05 M) and methanol mixture (25.75, v/v) was used at a flow rate of 1.0 ml/min . The eluate was monitored using a UV detector set at 345 nm. Ratio of peak area of analyte to I.S, was used for quantification of plasma samples. Usi ng this method the absolute recovery of PAT-5A from rat plasma was > 90% an d the limit of quantification was 0.05 mu g/ml. The intra-day relative stan dard deviation (RSD) ranged from 2.19 to 4.98% at 1.0 mu g/ml, 1.05 to 3.68 % at 10.0 mu g/ml and 3.14 to 5.08% at 50 mu g/ml. The inter-day RSD were 1 .6, 2.24 and 1.54% at 1, 10 and 50 mu g/ml, respectively. The method was ap plied to measure the plasma concentrations of PAT-SA in pharmacokinetic and bioavailability studies in male Wistar rats. (C) 2000 Elsevier Science B.V . All rights reserved.