HIGH-PERFORMANCE LIQUID-CHROMATOGRAPHIC ASSAY FOR THE QUANTITATION OFIRBESARTAN (SR-47436 BMS-186295) IN HUMAN PLASMA AND URINE

A selective, accurate, precise and reproducible high-performance liqui d chromatographic assay was developed for the quantitation of irbesart an, an angiotensin II antagonist, in human plasma and urine samples, T he method involved solid-phase extraction of irbesartan and internal s tandard (I.S.) using a 100-mg Isolute CN cartridge. A portion of the e luate was injected onto an ODS analytical column connected to a fluore scence detector that was set at an excitation wavelength of 250 nm and an emission wavelength of 371 nm. The mobile phase consisted of 50% a cetonitrile and a 50% weak phosphate-triethylamine solution, pH 3.5, a t a flow-rate of 0.8 ml/min. The assay was linear from 1 to 1000 ng/ml with both plasma and urine. In either matrix, the lower limit of quan titation was 1 ng/ml. The analyses of quality control samples indicate d that the nominal values could be predicted with an accuracy >95%. Th e inter- and intra-day coefficients of variation for the analyses in b oth matrices were <8%. Irbesartan was stable in both human plasma and urine for at least seven months at -20 degrees C. The application of t he assay to a pharmacokinetic study is described. (C) 1997 Elsevier Sc ience B.V.