title: LC method for therapeutic drug monitoring of levetiracetam: evaluation of the assay performance and validation of its application in the routine area.
abstract: OBJECTIVE
  An 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.
  
  
  METHODS
  A 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.
  
  
  RESULTS
  As pointed recently, the FDA, a weighted 1/x(2) 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 + or - 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.
  
  
  CONCLUSIONS
  The 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.
authors.affiliation: Pharmacy Department, Clínica Universidad de Navarra, c/ Pío XII s/n, 31008 Pamplona, Spain. lzufia@unav.es
authors.forename: Laura
authors.initials: L
authors.lastname: Zufía
authors.forename: Azucena
authors.initials: A
authors.lastname: Aldaz
authors.forename: Nerea
authors.initials: N
authors.lastname: Ibáñez
authors.forename: Joaquín
authors.initials: J
authors.lastname: Giráldez
authors.forename: César
authors.initials: C
authors.lastname: Viteri
mesh_terms: D002851:Chromatography, High Pressure Liquid / Q000379:methods*; D016903:Drug Monitoring / Q000379:methods*; D006801:Humans; D000077287:Levetiracetam; D057230:Limit of Detection; D016014:Linear Models; D010889:Piracetam / Q000031:analogs & derivatives* / Q000097:blood; D011786:Quality Control; D012307:Risk Factors; D054928:Validation Studies as Topic
chemical_list: D000077287:Levetiracetam; D010889:Piracetam