SIMULTANEOUS ESTIMATION OF RAMIPRIL AND ITS ACTIVE METABOLITE RAMIPRILAT IN HUMAN PLASMA BY ESI-LC-MS/MS

Abstract

A rapid and sensitive liquid chromatography tandem mass spectrometry method has been developed and validated for the simultaneous determination of ramipril and ramiprilat in human plasma. The solid-phase extraction technique was used for the extraction of ramipril and ramiprilat from human plasma. Enalapril was used as the internal standard (IS).Chromatography was performed on a Aquasil C18, 100mm×2.1mm, 5µ column, with the mobile phase consisting of acetonitrile-deionsed water (in a 65:35 ratio) and 1.0mLL^-1 ammonium trifluoroacetate solution (1.0M), followed by detection using mass spectrometry. The method involves a simple reversed isocratic chromatography condition and mass spectrometry detection, which enables detection at sub-nanogram levels. The method was validated and the lower limit of quantification for ramipril and ramiprilat was found to be 0.1 ngmL^−1and 0.1 ngmL^−1, respectively. The mean recovery for ramipril and ramiprilat ranged from 63.5 to 74.3%. This method increased the sensitivity and selectivity; resulting in high-throughput analysis of ramipril and ramiprilat using single IS in a single experiment for bioequivalence studies, with a chromatographic run time of 3.0 min only.