LIQUID-CHROMATOGRAPHIC SEPARATION AND MEASUREMENT OF OPTICAL ISOMERS OF AMINOGLUTETHIMIDE AND ITS ACETYL METABOLITE IN PLASMA, SALIVA, AND URINE

An accurate and specific liquid chromatographic method for the separat ion and analysis of the R(+) and S(-) enantiomers of both aminogluteth imide (AG) and its acetylated metabolite (AcAG) in plasma, saliva, and urine is described. The separation was achieved by use of two serial Chiralcel OD columns [cellulose tris(3,5-dimethylphenyl carbamate)] wi th a mixture of hexane/isopropanol/methanol (65:17.5:17.5, per volume) as a mobile phase. The flow rate was 0.7 ml/min, and the compounds we re detected in the effluent spectrophotometrically at 245 nm. The plas ma, saliva, or urine sample (300 mu l) was extracted with dichlorometh ane after the addition of an equal volume of acetate buffer (pH 5.6) t o the sample. The extraction recovery of the R(+) and S(-) enantiomers of AG and AcAG from plasma, saliva, and urine at different concentrat ions under these conditions was >80.9%. No interference from any endog enous substance or concomitantly used drug was observed. The ratio of the peak area of R(+) and S(-) enantiomers of both AG and AcAG/interna l standard was linearly (r greater than or equal to 0.995) related to concentration in the range 0.83-40.0 mu g/ml, and the coefficient of v ariation (CV) at different concentrations was consistently less than o r equal to 13%. We are presently employing this method to study the ph armacokinetics of each of these enantiomers in breast cancer patients.