Determination of carbamazepine and carbamazepine-10,11-epoxide in human serum and plasma by micellar electrokinetic capillary chromatography in the absence of electroosmosis

Therapeutic drug monitoring of carbamazepine (CBZ), a widely used antiepile ptic drug, is required for optimization of pharmacotherapy with this drug a nd for assessment of the patient's compliance to therapy. The suitability o f employing micellar electrokinetic capillary chromatography (MEKC) in the absence of electroosmosis for the determination of CBZ and its main metabol ite carbamazepine-10,11-epoxide (CBZE) in extracts of human serum and plasm a is reported. Using micelles formed by dodecyl sulfate, analyses performed in untreated fused-silica capillaries at acidic pH and in commercially ava ilable coated capillaries under application of reversed polarity are compar ed. Uncoated and polyvinyl alcohol coated capillaries proved to be unsuitab le for this purpose, whereas capillaries coated with linear polyacrylamide and N-acryloylaminoethoxyethanol and operated at pH 7.6 are shown to provid e high-quality and reliable data on a short time scale. Assay performance i s discussed via statistical analysis of the data produced from a set of qua lity control sera that contain up to 14 different drugs and via analysis of patient samples. Intraday and interday imprecision data for concentrations between 4.0 and 84 muM are demonstrated to be < 10%. Run times are shown t o be < 50% compared to those observed in conventional MEKC at alkaline pH ( i.e., in the presence of electroosmosis).