Jyk. Hsieh et al., FULLY AUTOMATED METHODS FOR THE DETERMINATION OF HYDROCHLOROTHIAZIDE IN HUMAN PLASMA AND URINE, Journal of pharmaceutical and biomedical analysis, 12(12), 1994, pp. 1555-1562
LC assays utilizing fully automated sample preparation procedures on Z
ymark PyTechnology(TM) Robot and BenchMate(TM) Workstation for the qua
ntification of hydrochlorothiazide (HCTZ) in human plasma and urine ha
ve been developed. After aliquoting plasma and urine samples, and addi
ng internal standard (IS) manually, the robot executed buffer and orga
nic solvent addition, liquid-liquid extraction, solvent evaporation an
d on-line LC injection steps for plasma samples, whereas, BenchMate(TM
) performed buffer and organic solvent addition, liquid-liquid and sol
id-phase extractions, and an-line LC injection steps for urine samples
. Chromatographic separations were carried out on Beckman Octyl Ultras
phere column using the mobile phase composed of 12% (v/v) acetonitrile
and 88% of either an ion-pairing reagent (plasma) or 0.1% trifluoroac
etic acid (urine). The eluent from the column was monitored with UV de
tector (271 nm). Peak heights for HCTZ and IS were automatically proce
ssed using a PE-Nelson ACCESSCHROM laboratory automation system. The
assays have been validated in the concentration range of 2-100 ng ml(-
1) in plasma and 0.1-20 mu g ml(-1) in urine. Both plasma and urine as
says have the sensitivity and specificity necessary to determine plasm
a and urine concentrations of HCTZ from low dose (6.25/12.5 mg) admini
stration of HCTZ to human subjects in the presence or absence of losar
tan.