Analysis of Captopril in Human Plasma Using Gas Chromatography-Mass Spectrometry (GCMS) with Solid-Phase Extraction (SPE)

A sensitive and simple Gas Chromatographic-Mass Spectrometric method was developed and validated for the determination of captopril in human plasma. Thiosalicylic acid was used as an internal standard, and plasma extraction was performed by solid phase extraction. The limit of quantification was 0.5 ng/mL with signal to noise ratio greater than 5. The calibration curve was linear from 1 to 160 ng/mL with r 2 greater than 0.99. The coefficient of variation for within and between assay imprecision of the standards and for the limit of quantification were 10 % and 7 %, respectively. The percentage of inaccuracy for withinand between-assay including lower and upper limits of quantitation were 8 % and 6 %, respectively. The absolute recovery of captopril and thiosalicylic acid in plasma were greater than 98 % and 99 %, respectively. The high sensitivity and accuracy of this method allowed us to measure low concentrations of captopril in plasma for bioequivalence studies in healthy subjects.