Determination of captopril in biological samples by highperformance liquidchromatography with ThioGlo(TM)3 derivatization

Captopril, a well-known angiotensin converting enzyme (ACE) inhibitor, is w idely used for treatment of arterial hypertension. Recent studies suggest t hat it may also act as a scavenger of free radicals because of its thiol gr oup. Therefore, the present study describes a rapid, sensitive and relative ly simple method for the detection of captopril in biological tissues with reverse-phase HPLC. Captopril was first derivatized with ThioGlo (TM)3 [3H- Naphto[2,1-b]pyran,9-acetoxy-2-(4-(2,5-dihydro-2,5-dioxo-1H-pyrrol-1-yl)phe nyl-3-oxo-)]. It was then detected by fluorescence-HPLC using an Astec C-18 column as the stationary phase and a water: acetonitrile:acetic acid:phosp horic acid mixture (50:50; 1 mL/L acids) as the mobile phase (excitation wa velength, 365 nm; emission wavelength, 445 nm). The calibration curve for c aptopril was linear over a range of 10-2500 nm and the coefficient of varia tion acquired for the within- and between-run precision for captopril was 0 .5 and 3.8%, respectively. The detection limit of captopril with this metho d was found to be 200 fmol/20 muL injection volume. Its relative recovery f rom biological samples was determined to the range from 93.3 to 105.3%. Bas ed on these results, we believe that our method is advantageous for captopr il determination. Copyright (C) 2001 John Wiley & Sons, Ltd.