Determination of the enantiomers of indoprofen in blood plasma by high-performance liquid chromatography after rapid derivatization by means of ethyl chloroformate.

A rapid method for the determination of (+)- and (-)-indoprofen in blood plasma has been developed and applied to pharmacokinetic work. By means of ethyl chloroformate, indoprofen is coupled to leucinamide, a reaction which is complete in less than 3 min at room temperature. The diastereoisomeric derivatives are then separated by reversed-phase high-performance liquid chromatography. In two surgical patients given racemic indoprofen intravenously, the pharmacologically active (+)-enantiomer had a lower clearance and a lower distribution volume than the (-)-enantiomer, which gave it a slightly longer half-life.