Enantioselective determination of diprafenone in human plasma

A sensitive (10.0 ng/ml) and stereoselective HPLC method for analysis of S(-)- and R(+)-diprafenone in human plasma has been developed. The assay is based on derivatization with homochiral R(-)-1-(1-naphthyl)ethyl isocyanate to give the diastereomeric derivates and their separation and quantitation using HPLC with UV-detection (220 nm). Details of this stereoselective assay procedure which has already been applied to the multisample analyses from a human pharmacokinetic study are described. The data obtained indicated that the stereoselective disposition of diprafenone enantiomers is quite different from their structural and pharmacological analog propafenone.