LC method for therapeutic drug monitoring of levetiracetam: Evaluation of the assay performance and validation of its application in the routine area

ObjectivesAn accurate and precise high-performance liquid chromatographic method using diode array detection for the determination of levetiracetam in human plasma has been developed and validated for use in pharmacokinetic studies.MethodsA harmonized validation strategy based on the accuracy profiles was used to select the most appropriate regression model and to determine the limits of quantitation as well as the concentration range of the developed analytical procedure. On the other hand, the present paper also shows this validation approach as a suitable tool to guaranty the quality of the results obtained by the use of the analytical validated methodology for plasma levetiracetam determination in a routine setting and to ensure the risk of obtaining the future measurements outside the previously fixed acceptance limits.ResultsAs pointed recently, the FDA, a weighted 1/x2 quadratic regression model ranging from 0.53 to 107.00 mg/L was selected as the simplest calibration model that maximized the accuracy all over the range. Relative bias was < 5%, assay imprecision was always < 6% and mean extraction recovery from plasma was > 90%. So, accuracy did not exceed the acceptance limits settled at ± 20% according to the FDA or Washington conference regulatory requirements for bioanalytical methods. Internal quality control has been assessed over a 2 year time period. All controls were essentially found to provide levetiracetam concentrations within the target range according to the FDA.ConclusionsThe validated analytical procedure complies with strongest regulatory standards. The validated method has a sufficiently rapid turnaround time and their results are good enough to enable the laboratory to routinely provide useful and accurate pharmacokinetic data in time to adjust patient regimens.