Therapeutic drug monitoring of antiepileptics by capillary electrophoresis- Characterization of assays via analysis of quality control sera containing 14 analytes

Quality assurance is an important aspect in therapeutic drug monitoring (TD M). Capillary electrophoresis (CE) assays for determination of (i) ethosuxi mide via direct injection of serum or plasma, (ii) lamotrigine after protei n precipitation by acetonitrile and analysis of an aliquot of the acidified supernatant, and (iii) carbamazepine and carbamazepine-10, 11-epoxide afte r solute extraction followed by analysis of the reconstituted extract are c haracterized via analysis of a large number of commercial quality control s era containing up to 14 analytes (9 of them are anticonvulsants) in sub-the rapeutic, therapeutic and toxicologic concentration levels. CE data obtaine d in single determinations are shown to compare well with the spike values and the mean of data determined in other laboratories using immunoassays an d/or high-performance liquid chromatography, values that are reported by th e external quality control scheme. Carbamazepine and ethosuximide drug leve ls are also shown to agree well with those determined in our departmental d rug assay laboratory using automated immunoassays. The presented data revea l the effectiveness of assay assessment via analysis of quality control ser a and confirm the robustness of the assays for TDM in a routine setting. (C ) 2001 Elsevier Science B.V. All rights reserved.