Development and validation of high performance liquid chromatographic method for analysis of clozapine

In this study a rapid, simple and sensitive assay to quantify clozapine in human plasma by using reverse phase high performance liquid chromatographic method has been developed. Clozapine was extracted from human plasma using a mixture of chloroform: n-hexane 50:50 employing liquid- liquid extraction method. The calibration curve was found to be linear in the concentration range of 25-800 ng/ml. The inter day and intra day assay accuracy and precision fulfilled the criteria specified by USFDA, Guidance for industry: bioanalytical method validation. Clozapine was found to be stable in human plasma after 6 h incubation at room temperature, 50 days storage at -27[degree sign] C and freeze thaw cycles, as well as after reconstitution with mobile phase after 24 h of storage in refrigerator. The validated method offers the advantage of using minimum injection volume [25micro l] and plasma sample volume [300micro l]. The extraction method is simple and single step with no back extraction step, thus, making this method applicable to determination of pharmacokinetic profiles and parameters

Simultaneous determination of trihexyphenidyl, chlorpromazine and clozapine in blood by GC-MS / 法医学杂志

OBJECTIVE@#To develop a method to measure trihexyphenidyl, chlorpromazine and clozapine in human blood with GC-MS.@*METHODS@#The specimens were alkalized (pH > 10) and extracted with V (benzene):V(ethyl acetate) = 1:1, and qualitatively analyzed using GC-MS-Full Scan with internal standard SKF525A. The specimens were alkalized (pH > 10) and extracted with V(benzene):V(ethyl acetate) = 1:1, and quantitatively analyzed using GC-MS-SIM with internal standard diazepam-d5.@*RESULTS@#The lowest detection limits of trihexyphenidyl, chlorpromazine and clozapine were 0.3, 0.3 and 0.7 ng/mL (S/N > or = 3) respectively. The calibration curve in 20-10 000 ng/mL showed a good linear distribution. The recovery rate was 79.9% to 85.5%. The RSDs of intraday and interday were less than 5.1%.@*CONCLUSION@#The established method was simple, sensitive and accurate for simultaneous determination of trihexyphenidyl, chlorpromazine and clozapine in human blood, and can be applied in forensic toxicological cases.

Simultaneous determination of clozapine, olanzapine and mirtazapine in human plasma by LC-MS/MS / 法医学杂志

OBJECTIVE@#To develop a method for determination of clozapine, olanzapine and mirtazapine in human plasma by liquid chromatography-tandem mass spectrometry(LC-MS/MS).@*METHODS@#Clozapine, olanzapine and mirtazapine were extracted from plasma samples by using diethyl ether and separated by Agilent Zorbax SB-C18 column(2.1 mm x 150 mm, 5 microm). Electrospray ionization source was applied, positive ion mode was used to detect and multiple reaction monitoring mode was used to quantify clozapine, olanzapine and mirtazapine. Carbamazepine was the internal standard.@*RESULTS@#The detection limits of clozapine, olanzapine and mirtazapine were within 0.41-0.92 ng/mL. The calibration curve in the concentration range of 10.0-2000.0 ng/mL showed a good linear distribution (r > or = 0.992 4). The average extraction recoveries were within 65.7%-94.2%. Intra-day RSD and inter-day RSD were less than 6% (n = 5).@*CONCLUSION@#This method seems to be quite specific, sensitive and accurate, and can be used to detect clozapine, olanzapine and mirtazapine in forensic and clinical analytic toxicology.