Development and Validation of GC-MS Method for Determination of Metoprolol in Human Urine

Abstract

This paper describes a specific, sensitive, and accurate gas chromatography-mass spectrometry method for determination of metoprolol in human urine after derivatization with N-Methyl-N-(trimethylsilyl) trifluoroacetamide (MSTFA). The method employed a one-step extraction of metoprolol from human urine with a mixture of ethylacetate and diethylether (2:1, v/v) at basic pH using atenolol as internal standard. Calibration curves were linear over the concentration range 50-3000 ng/mL. Intra-and inter-day precision values for metoprolol in human urine were less than 6.0%. The analytical recovery of metoprolol from human urine averaged 90.88%. The limits of detection and quantification of metoprolol were 5.0 and 15 ng/mL, respectively. Also, the developed and validated method was successfully applied to a patient with hypertension who had been given an oral tablet of 100 mg metoprolol.