Detection of ketorolac enantiomers in human plasma using enantioselective liquid chromatography

A high-performance liquid chromatographic method for the determination of the enantiomers of ketorolac in human plasma has been developed. Plasma samples containing ketorolac were acidified and extracted into diethyl ether. The ethereal extract was evaporated to dryness and the residue reconstituted in mobile phase before injection onto a Chiral-AGP column. The mobile phase was 2-propanol-20 mM potassium dihydrogenphosphate buffered to pH 7 (0.5:99.5, v/v). Detection was by ultraviolet absorbance at 320 nm. The detection limit was 5 ng/ml for each enantiomer. The method has been applied to determine the concentration of ketorolac enantiomers during an infusion of the racemic drug and has proven to be rapid and sensitive.