OBJECTIVE Clozapine is one of the most effective drugs for resistant schizophrenia, but its severe metabolic and hematological side effects limit the use of clozapine. It has been reported that clozapine blood concentrations should be maintained between 350-600 ng/mL. Our aim was to develop a determination method for clozapine and its main metabolites norclozapine and clozapine-N-oxide, to perform validation studies and to investigate the change of various biochemical parameters in patients using clozapine. METHODS A liquid chromatography-tandem mass spectrometry (LC-MS/MS) method was developed and validated for clozapine measurement. Thus, blood samples were collected from 38 patients with schizophrenia and 32 healthy volunteers. Biochemical and hematological parameters were measured by Beckman-Coulter AU 5800 (Beckman Coulter, Brea, USA) and Beckman Coulter LH 780 analyzer (Beckman Coulter, Miami, FL, USA), respectively. Hormone levels were analyzed using Cobas 6000 analyzer (Roche Diagnostics, Germany). RESULTS The LCMS/MS method was linear between 1.22-2500 ng/mL (r2 = 0.9971) for clozapine. The retention times of clozapine, norclozapine and clozapine-N-oxide were 0.92, 0.89 and 0.95, respectively. Blood glucose (GLU) (p = 0.025), low density lipoprotein (LDL-cholesterol) (p = 0.015), triglyseride (TG) (p = 0.042) and total cholesterol (TC) (p = 0.024) levels were higher; hemoglobin (HGB) (0.015), mean corpuscular hemoglobin (MCH) (0.036), red blood cell count (RBC) (0.020), neutrophil (NEU) (0.034), and platelet (PLT) (P = 0.005) levels were lower in the clozapine group. CONCLUSIONS This LC-MS/MS method was rapid, simple, cost-effective and suitable for the routine clozapine monitoring. Furthermore, norclozapine and clozapine-N-oxide were also determined. Monitoring of metabolic and hematological parameters with clozapine levels is very important. However, the limitations of the study were that the method was not validated for norclozapine and clozapine-N-oxide, so the validation parameters were not evaluated for these two metabolites.

中文翻译：

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通过验证的质谱方法测定血清氯氮平浓度与血液学参数之间的关系。

目的氯氮平是抗精神分裂症最有效的药物之一，但其严重的代谢和血液学副作用限制了氯氮平的使用。据报道，氯氮平的血药浓度应保持在350-600 ng / mL之间。我们的目的是开发一种测定氯氮平及其主要代谢物降氯氮平和氯氮平-N-氧化物的方法，进行验证研究并调查使用氯氮平的患者的各种生化参数的变化。方法建立了液相色谱-串联质谱（LC-MS / MS）方法，并验证了氯氮平的测定方法。因此，从38位精神分裂症患者和32位健康志愿者中采集了血液样本。生化和血液学参数由Beckman-Coulter AU 5800（Beckman Coulter，Brea，美国）和贝克曼库尔特LH 780分析仪（美国佛罗里达州迈阿密的贝克曼库尔特）。使用Cobas 6000分析仪（德国Roche Diagnostics）分析激素水平。结果氯氮平的LCMS / MS方法在1.22-2500 ng / mL（r2 = 0.9971）之间呈线性关系。氯氮平，去甲氯氮平和氯氮平-N-氧化物的保留时间分别为0.92、0.89和0.95。血糖（GLU）（p = 0.025），低密度脂蛋白（LDL-胆固醇）（p = 0.015），甘油三酸酯（TG）（p = 0.042）和总胆固醇（TC）（p = 0.024）较高; 血红蛋白（HGB）（0.015），平均红细胞血红蛋白（MCH）（0.036），红细胞计数（RBC）（0.020），中性粒细胞（NEU）（0.034）和血小板（PLT）的水平较低（P = 0.005）在氯氮平组中。结论这种LC-MS / MS方法快速，简便，具有成本效益，适合常规氯氮平监测。此外，还测定了正氯氮平和氯氮平-N-氧化物。用氯氮平水平监测代谢和血液学参数非常重要。但是，该研究的局限性在于该方法未针对去甲氯氮平和氯氮平-N-氧化物进行验证，因此未针对这两种代谢物评估验证参数。