Trace analysis of zotepine and its active metabolite in plasma by capillary electrophoresis with solid phase extraction and head-column field-amplified sample stacking.
A sensitive high-performance capillary zone electrophoresis (CZE) with head-column field-amplified sample stacking (FASS) in binary system has been developed for the simultaneous determination of zotepine and its active metabolite, norzotepine, in human plasma. The separation of zotepine and norzotepine was performed using a background electrolyte consisting of 50% ethylene glycol-borate buffer (20mM, pH 8.0) solution with 20% methanol as the running buffer and on-column detection at 200 nm. Under the optimal FASS-CZE condition, good separation with high efficiency and short analysis time is achieved. Several parameters affecting the separation and sensitivity of the drug were studied, including sample matrix, pH and concentrations of the borate buffer, ethylene glycol and methanol. Using clozapine as an internal standard, the linear ranges of the method for the determination of zotepine and norzotepine in human plasma were over 3-100 ng/mL; the detection limits of zotepine and norzotepine in plasma were 2 and 1 ng/mL, respectively. A sample pretreatment by means of solid-phase extraction (SPE) with subsequent quantitation by FASS-CZE was used. The application of the proposed method for determination of zotepine and norzotepine in plasma collected after oral administration of 125 mg zotepine in one schizophrenic patient was demonstrated.
Chou
Yu-Wei
YW
Graduate Institute of Pharmaceutical Sciences, Kaohsiung Medical University, Kaohsiung 807, Taiwan.
Huang
Wei-Shan
WS
Chen
Cheng-Chung
CC
Lin
Shun-Jin
SJ
Wu
Hsin-Lung
HL
Chen
Su-Hwei
SH
D000328:Adult; D014150:Antipsychotic Agents / Q000097:blood*; D002021:Buffers; D003988:Dibenzothiepins / Q000097:blood*; D019075:Electrophoresis, Capillary / Q000295:instrumentation / Q000379:methods*; D006801:Humans; D008297:Male; D012015:Reference Standards
D014150:Antipsychotic Agents; D002021:Buffers; D003988:Dibenzothiepins; C022172:zotepine