DEVELOPMENT AND VALIDATION OF A CHIRAL HPLC METHOD FOR THE QUANTITATION OF METHOCARBAMOL ENANTIOMERS IN HUMAN PLASMA

An isocratic chiral HPLC method was developed and validated for the qu antitation of methocarbamol enantiomers in human plasma. Methocarbamol and an internal standard were extracted with ethyl ether. Chiral sepa ration was achieved on coupled Spherisorb CN and Chiralcel OD columns with a mobile phase of ethanol hexane (30:70, v/v). The detection was by UV at 272 nm. Linearity was established at 0.5 - 50 mu g/ml (r > 0. 998). Interday precision and accuracy of the calibration standards wer e demonstrated by 0.8 to 9.4% coefficients of variance (C.V.) and -5.2 to +3.8% relative error (R.E.). Quality controls showed interday prec ision and accuracy of 4.4 to 7.2% C.V. and +0.4 to +5.5% R.E. Recovery of methocarbamol enantiomers was 77 - 84%. No interconversion of the methocarbamol enantiomers was observed during process of storage, extr action nor chromatograph. Reproducibility and stability of the analyti cal columns were demonstrated.