QUANTITATION OF AMLODIPINE IN HUMAN PLASMA BY LCMS/MS ASSAY

­­­­­­­­­­­­­­­­­Objective: To develop and validate a simple, precise, and rapid liquid chromatographic-tandem mass spectrometric (LC-MS/MS) method for quantification of amlodipine in human plasma.Methods: Chromatographic analysis was performed on Atlantis dC18 column (2.1 x 100 mm, 3 µm) with a mobile phase consisting of acetonitrile and 10 mM formic acid (80:20, v: v) that was delivered at a flow rate of 0.3 ml/min. The eluents were monitored using electrospray ionization in the positive ion mode set at transition 409 → 238.4 and 254.3 → 43.9 for amlodipine and tizanidine hydrochloride (IS), respectively. The method was validated for linearity, accuracy, precision, and recovery as per US-FDA guidelines.Results: The retention times of amlodipine and tizanidine (IS) were 1.26 and 1.22 respectively. The relationship between amlodipine concentration and peak height ratio of amlodipine to the IS was linear (R2³ 0.9868) in the range of 0.2–20 ng/ml, and the intra-and inter-day coefficient of variations and bias were ≤14.4% and ≤13.6% and ≤13.7% and ≤11.2%, respectively.Conclusion: The proposed method is simple, precise, and accurate for rapid measurement of amlodipine level using 0.5 ml human plasma. Further, the assay was successfully applied to determine amlodipine level in human plasma samples obtained from a healthy volunteer