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Enantioselective Determination Of S- And R-Isomers Of Ibuprofen In Plasma By Ultra-Performance Liquid Chromatography – Tandem Mass Spectrometry

A new method of enantioselective determination of S- and R-isomers of ibuprofen in human plasma by ultraperformance liquid chromatography with tandem mass spectrometric detection using solid-phase extraction was developed. For enantioselective separation of ibuprofen isomers, a LUX Cellulose-3 chiral chromatographic column was used. Complete separation of the enathiomer peaks is achieved in the isocratic elution conditions with a mobile phase ratio of 0.05 % formic acid solution (%): methanol (%) = 30 : 70 (v/v) and a flow rate of 0.2 mL/min. The mass spectrometric detection was performed at negative ionization mode with multiple reaction monitoring, using the transitions at 205.13 > 161.14 Da and 208.09 > 164.03 Da for ibuprofen enantiomers and deuterated ibuprofen (internal standard), respectively. The method validation included the evaluation of the selectivity, linearity, lower limit of quantification (LLOQ), within-run and between-run precision and accuracy. The LLOQ for the two enantiomers was 100 ng/mL in plasma. The calibration curves showed good linearity of each enantiomers in the ranges from 100 to 60000 ng/mL. The method was successfully applied to a pharmacokinetic study of ibuprofen enantiomers in human plasma.