Simultaneous quantification of ramipril, glimepiride and metformin in human plasma by ultra-performance liquid chromatography – tandem mass spectrometry

Abstract

Ramipril (RAM), glimepiride (GLM) and metformin (MET) are recently formulated together for the treatment of diabetes and cardiovascular disorders. This work introduces a liquid chromatography-tandem mass spectrometric (LC-MS/MS) method for the simultaneous determination of the three drugs in human plasma after liquid-liquid extraction. This method made use of atorvastatin as internal standard (IS). Analytes were recovered from plasma by n-hexane: butanol (50:50%, v/v) and subsequently separated on Waters Acquity TM UPLC BEH shield RP-C18 column using methanol: water containing 0.1% formic acid (90: 10%, v/v) as a developing system. The calibration curves were linear (r 2 > 0.99) over a range of 0.1 -1000 ng/mL for RAM & GLM and 250 -2000 ng/mL for MET. The intra-day and inter-day precisions were below 14.32% and the accuracy was all within ±15%. Moreover, other validation parameters for the proposed method like matrix effect, selectivity, recovery and stability were adopted. The proposed method can be applied for th e sensitive and selective quantification of the analytes in bioavailability and pharmacokinetics studies.