[A reversed phase HPLC method with pre-column derivatization to determine propafenone enantiomers in human plasma]

A reversed phase HPLC method to stereoselectively determine enantiomers of propafenone in human plasma has been developed. After extraction of 1 ml plasma with 3 ml of n-C6H14:CH2Cl2:2-C3H7OH (100:50:5, v/v) and dried under N2, the enantiomers of propafenone were allowed to react with homochiral S(+)-1-(1-naphthyl) ethyl isocyanate (5.66 micrograms in 60 microliters CH2Cl2) at RT for 30 min, to give the diastereomeric derivatives. Their separation was achieved using HPLC with a C18-column and UV-detection (220 nm) and the enantiomeric ratios were measured. The concentration of each enantiomer were then calculated using the enantiomeric ratios and the racemic propafenone concentrations previously measured. This method after validation procedures has been applied to the multisample analyses of a human pharmacokinetic study with 10 healthy volunteers after an oral dose of 300 mg propafenone hydrochloride. The method was shown to be sensitive (7.5 ng.ml-1), convenient and reproducible.