Quantification of the steady-state plasma concentrations of clozapine and N-desmethylclozapine in Japanese patients with schizophrenia using a novel HPLC method and the effects of CYPs and ABC transporters polymorphisms
Quantification of the steady-state plasma concentrations of clozapine and N-desmethylclozapine in Japanese patients with schizophrenia using a novel HPLC method and the effects of CYPs and ABC transporters polymorphisms
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DOI:
10.1177/0004563216686377
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发表时间:
2017-11-01
影响因子:
2.2
通讯作者:
Miura, Masatomo
中科院分区:
文献类型:
--
作者:
Akamine, Yumiko;Sugawara-Kikuchi, Yuka;Miura, Masatomo
Background This study developed a novel high-performance liquid chromatography (HPLC) method for the simultaneous quantification of clozapine and its active metabolite, N-desmethylclozapine, in human plasma and investigated the effects of various factors, including genetic polymorphisms in cytochrome P450 (CYP) 2D6, CYP3A5, ABCB1 and ABCG2, on the steady-state plasma trough concentrations (C-0) of clozapine and N-desmethylclozapine in Japanese patients with schizophrenia.Methods Forty-five patients had been receiving fixed doses of clozapine for at least four weeks. The CYP2D6 (CYP2D6*2, CYP2D6*5, CYP2D6*10), CYP3A5 (CYP3A5*3), ABCB1 (1236C>T, 2677G>T/A, 3435C>T) and ABCG2 (421C>A) genotypes were identified by polymerase chain reaction.Results The within- and between-day coefficients of variation (CV) were less than 11.0%, and accuracy was within 9.0% over the linear range from 10 to 2500ng/mL for both analytes, and their LOQs were each 10ng/mL. The median C-0/dose (C-0/D) ratios of clozapine were significantly higher in patients with the ABCG2 421A allele than in those with the 421C/C genotype (P=0.010). However, there were no significant differences in C-0/D ratios of clozapine and N-desmethylclozapine among ABCB1, CYP2D6 or CYP3A5 genotypes. In multiple regression analysis, including polymorphisms, age, body weight and biochemical data of patients, the ABCG2 polymorphism alone was correlated with the C-0/D ratios of clozapine (R-2=0.139, P=0.016).Conclusions Among the various CYPs and drug transporters, BCRP appeared to most strongly influence clozapine exposure. Knowledge of the patient's ABCG2 421C>A genotype before initiating therapy may be useful when making dosing decisions aimed at achieving optimal clozapine exposure.