DERIVATIZATION OF ROSUVASTATIN AS METHYL ESTER FOR ITS ANALYSIS BY GAS CHROMATOGRAPHY-MASS SPECTROMETRY IN PLASMA

Abstract

A new analytical procedure for rapid and selective derivatization of rosuvastatin directly in plasma into their corresponding methyl esters was developed for gas chromatography-mass spectrometry analysis. This work is the first method of selective derivatization of the carboxyl group from rosuvastatin to methyl ester. The lipids from plasma were extracted with heptane before derivatization. The methyl esters were obtained by reaction with methyl iodide in solution of dimethyl sulfoxide and in the presence of anhydrous potassium carbonate. The optimal conditions for selective methylation have been established. The derivatization was carried out in 2 min. The method was validated for the analysis of rosuvastatin in plasma. The methyl ester of rosuvastatin was identified by electron ionization mass spectrometry. The electron ionization mass spectrometer detector response was linear up to 300 ng/mL. The limit of detection and limit of quantification values in total ion chromatogram method were 0.4 ng/mL and 1.2 ng/mL, respectively.