Determination of Hydrochlorothiazide in Human Plasma by HPLC: Application to a Pharmacokinetic Study

In this study, a simple, rapid and sensitive high performance liquid chromatography (HPLC) method is developed for the determination of hydrochlorothiazide (HCT) in human plasma samples using fluconazole as the internal standard (IS). Sample preparation was accomplished through liquid-liquid extraction, and chromatographic separation was carried out on an Agilent ZORBAX Eclipse XDB-C18 (4.6 x 150 mm, 5 mu m) at 30 degrees C. Mobile phase composed of a mixture of acetonitrile-0.1% trifluoroacetic acid-water (20: 40: 40) at flow rate of 0.8 mL/min. Wavelength was set at 266 nm. The chromatographic retention times of HCT and IS were 4.2 and 5.5 min, respectively. The lower limit of quantitation (LLOQ) was 5 ng/mL, and no interferences were detected in the chromatograms. The devised HPLC method was validated by evaluating its intra-and inter-day precisions and accuracies in a linear concentration range between 5 and 400 ng/mL. The method was successfully applied to a pharmacokinetic study of oral HCT tablets in Chinese healthy volunteers.