title: Analysis of carbamazepine and its five metabolites in serum by large-volume sample stacking-sweeping capillary electrophoresis.
abstract: This study establishes a method, using different buffer conductivities and large-volume sample stacking (LVSS)-sweeping capillary electrophoresis, for analysis of carbamazepine (CBZ) and its five metabolites in serum. The capillary (50/60 cm) was filled with a high concentration of background electrolyte (150 mM phosphate, pH 3.5, containing 15 % methanol), followed by a large volume of samples (10 psi, 20 s) with low-concentration buffers (5 mM phosphate, pH 3.5, with 5 % methanol). When high voltage was applied (-20 kV), the sodium dodecyl sulfate (SDS) started to sweep the analytes to an outlet. Meanwhile, the analytes decelerated at the boundary between low- and high-conductivity buffers. Finally, a narrow sample zone was formed. The procedure of sweeping and separation was simultaneously carried out by a sweeping buffer (150 mM phosphate, pH 3.5) with 15% methanol and 50 mM SDS added, and the detection was performed by UV at 214 nm. The method was validated for linearity (r >/= 0.997), precision, and accuracy. The calibration curves were established for CBZ and its five metabolites between 0.03-25 and 0.03-3 μg/mL. The limits of detection (S/N = 3) were 0.01 μg/mL for each analyte. Compared with simple MEKC (0.5 psi, 5 s), this system can improve the sensitivity about 300-fold. Finally, this method was successfully applied to five patients, who had taken 200 mg CBZ daily, and CBZ levels were found to be from 3.72 to 5.82 μg/mL.
authors.affiliation: School of Pharmacy, College of Pharmacy, Kaohsiung Medical University, 100 Shih-Chuan 1st RD, Kaohsiung 807, Taiwan.
authors.forename: Yan-Yu
authors.initials: YY
authors.lastname: Lin
authors.forename: Chun-Chi
authors.initials: CC
authors.lastname: Wang
authors.forename: Yu-Hsiang
authors.initials: YH
authors.lastname: Ho
authors.forename: Cheng-Sheng
authors.initials: CS
authors.lastname: Chen
authors.forename: Shou-Mei
authors.initials: SM
authors.lastname: Wu
mesh_terms: D002138:Calibration; D002220:Carbamazepine / Q000032:analysis* / Q000097:blood / Q000378:metabolism; D002623:Chemistry Techniques, Analytical; D004553:Electric Conductivity; D019075:Electrophoresis, Capillary / Q000379:methods*; D006801:Humans; D006863:Hydrogen-Ion Concentration; D007118:Immunoassay / Q000379:methods; D016014:Linear Models; D010710:Phosphates / Q000032:analysis; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity; D013997:Time Factors
chemical_list: D010710:Phosphates; D002220:Carbamazepine