Determination of levetiracetam in human plasma with minimal sample pretreatment

We here present a method for the routine quantification of the novel antiepileptic drug levetiracetam in human serum by HPLC-UV. The procedure is very easy, quick, inexpensive and rugged. The sample preparation consists only in the precipitation of serum proteins by perchloric acid and extraction of unpolar components by cyclohexane. The aqueous phase containing the analyte levetiracetam is injected onto a porous graphitic carbon analytical HPLC-column and separated by gradient elution with diluted phosphoric acid/acetonitrile. Detection is carried out at a wavelength of 205 nm. The calibration function is linear in the range of 1-75 microg/ml. The detection limit is 0.1 microg/ml. Using four quality control sample concentrations, the inter-day relative standard deviations (R.S.D.) are lower than 3% and the accuracies are better than 6%. The respective inter-day values are: R.S.D. < 4% and accuracies better than 2%. Frequently co-administered antiepileptic drugs do not interfere with the assay. The method has been successfully applied to patient samples.