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Hrichi H, Kouki N, Elkanzi NAA. Chromatographic Methods for the Analysis of the Antipsychotic Drug Clozapine and Its Major Metabolites: A Review. J Chromatogr Sci 2024:bmae016. [PMID: 38576210 DOI: 10.1093/chromsci/bmae016] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/04/2023] [Revised: 02/21/2024] [Accepted: 03/14/2024] [Indexed: 04/06/2024]
Abstract
Clozapine (CLZ), a second-generation antipsychotic, can effectively reduce schizophrenia, bipolar disorder and major depression symptoms. This review provides an overview of all reported chromatographic methods (62 references) for the quantification of CLZ and its two main metabolites, norclozapine and clozapine N-oxide in pharmaceutical formulations, biological matrices and environmental samples.
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Affiliation(s)
- Hajer Hrichi
- Chemistry Department, College of Science, Jouf University, P.O. Box: 2014, Sakaka, Saudi Arabia
| | - Noura Kouki
- Department of Chemistry, College of Science, Qassim University, Buraidah 51452, Saudi Arabia
| | - Nadia Ali Ahmed Elkanzi
- Chemistry Department, College of Science, Jouf University, P.O. Box: 2014, Sakaka, Saudi Arabia
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Clozapine and norclozapine monitoring in plasma following surfactant assisted dispersive liquid–liquid microextraction. SEPARATION SCIENCE PLUS 2022. [DOI: 10.1002/sscp.202100068] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
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Rahman H, Haque SM, Siddiqui MR. A Comprehensive Review on Importance and Quantitation of Atypical Antipsychotic Drugs and their Active Metabolites in Commercial Dosage Forms. CURR PHARM ANAL 2020. [DOI: 10.2174/1573412915666190328214323] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Background:
Schizophrenia is a severe mental illness that affects more than twenty-one
million people throughout the world. Schizophrenia also causes early death. Schizophrenia and other
related psychotic ailments are controlled by the prescription of antipsychotic drugs, which act by blocking
certain chemical receptors in the brain and thus relieves the symptoms of psychotic disorder. These
drugs are present in the different dosage forms in the market and provided in a certain amount as per the
need of the patients.
Objective:
Since such medications treat mental disorders, it is very important to have a perfect and accurate
dose so that the risk factor is not affected by a higher or lower dose, which is not sufficient for
the treatment. For accurate assay of these kinds of drugs, different analytical methods were developed
ranging from older spectrophotometric techniques to latest hyphenated methods.
Results:
The current review highlights the role of different analytical techniques that were employed in
the determination and identification of antipsychotic drugs and their metabolites. Techniques such as
spectrophotometry, fluorimetry, liquid chromatography, liquid chromatography-mass spectrometry, gas
chromatography, and gas chromatography-mass spectrometry employed in the method development of
such antipsychotic drugs were reported in the review. Different metabolites, identified using the hyphenated
techniques, were also mentioned in the review. The synthesis pathways of few of the metabolites
were mentioned.
Conclusion:
The review summarizes the analyses of different antipsychotic drugs and their metabolites.
A brief introduction of illnesses and their symptoms and possible medications were highlighted. Synthesis
pathways of the associated metabolites were also mentioned.
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Affiliation(s)
- Habibur Rahman
- Department of General Studies, Jubail Industrial College, P.O. Box No. 10099, Zip Code–31961, Jubail, Saudi Arabia
| | - S.K. Manirul Haque
- Department of Chemical & Process Engineering Technology, Jubail Industrial College, P.O. Box No 10099, Zip Code- 31961, Jubail, Saudi Arabia
| | - Masoom Raza Siddiqui
- Chemistry Department, College of Science, King Saud University, Riyadh 11451, Saudi Arabia
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Schoretsanitis G, Kane JM, Ruan CJ, Spina E, Hiemke C, de Leon J. A comprehensive review of the clinical utility of and a combined analysis of the clozapine/norclozapine ratio in therapeutic drug monitoring for adult patients. Expert Rev Clin Pharmacol 2019; 12:603-621. [DOI: 10.1080/17512433.2019.1617695] [Citation(s) in RCA: 37] [Impact Index Per Article: 7.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/16/2023]
Affiliation(s)
- Georgios Schoretsanitis
- Zucker Hillside Hospital, Psychiatry Research, Northwell Health, Glen Oaks, NY, USA
- Hofstra Northwell School of Medicine, Hempstead, NY, USA
- Feinstein Institute for Medical Research, Manhasset, NY, USA
| | - John M. Kane
- Zucker Hillside Hospital, Psychiatry Research, Northwell Health, Glen Oaks, NY, USA
- Hofstra Northwell School of Medicine, Hempstead, NY, USA
- Feinstein Institute for Medical Research, Manhasset, NY, USA
| | - Can-Jun Ruan
- Laboratory of Clinical Psychopharmacology & The National Clinical Research Centre for Mental Disorders & Beijing Key Lab of Mental Disorders, Beijing Anding Hospital, Capital Medical University, Beijing, China
| | - Edoardo Spina
- Department of Clinical and Experimental Medicine, University of Messina, Messina, Italy
| | - Christoph Hiemke
- Department of Psychiatry and Psychotherapy, University Medical Center of Mainz, Mainz, Germany
| | - Jose de Leon
- University of Kentucky Mental Health Research Center at Eastern State Hospital, Lexington, KY, USA
- Psychiatry and Neurosciences Research Group (CTS-549), Institute of Neurosciences, University of Granada, Granada, Spain
- Biomedical Research Centre in Mental Health Net (CIBERSAM), Santiago Apostol Hospital, University of the Basque Country, Vitoria, Spain
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Imaz ML, Oriolo G, Torra M, Soy D, García-Esteve L, Martin-Santos R. Clozapine Use During Pregnancy and Lactation: A Case-Series Report. Front Pharmacol 2018; 9:264. [PMID: 29636684 PMCID: PMC5881137 DOI: 10.3389/fphar.2018.00264] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/11/2018] [Accepted: 03/09/2018] [Indexed: 12/16/2022] Open
Abstract
The current prescription of clozapine in psychotic women of reproductive age makes it crucial to understand its pharmacokinetics during pregnancy and lactation as well as its risk profile for neonatal outcome. The aim of this case series was to provide new evidence on the pharmacokinetic features of clozapine that determine its passage through the placenta and amniotic fluid, as well as the neonatal clozapine elimination half-life (t1/2). This case series demonstrates for the first time that clozapine might show partial placental passage similar to other atypical antipsychotics. Clozapine levels decreased during the first few days in nursing infants. The half-life of clozapine in neonates was slightly higher than previously estimated. Clozapine use in pregnancy may be associated with diabetes mellitus, especially if there is a family history of this disease. Although no acute toxicological effects were observed in the intrauterine exposed newborn, close follow-up of pregnancy is recommended. However, these results must be taken with caution being a case series with small sample size
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Affiliation(s)
- M Luisa Imaz
- Perinatal Psychiatry Program, Department of Psychiatry and Psychology, Hospital Clínic, Institut d'Investigacions Biomèdiques August Pi i Sunyer (IDIBAPS), Barcelona, Spain.,Department of Medicine, University of Barcelona, Barcelona, Spain
| | - Giovanni Oriolo
- Department of Medicine, University of Barcelona, Barcelona, Spain.,Department of Psychiatry and Psychology, Hospital Clínic, Institut d'Investigacions Biomèdiques August Pi i Sunyer (IDIBAPS), Barcelona, Spain
| | - Mercè Torra
- Department of Medicine, University of Barcelona, Barcelona, Spain.,Pharmacology and Toxicology Laboratory, Biochemistry and Molecular Genetics Service, Biomedical Diagnostic Center (CBD), Hospital Clínic, Institut d'Investigacions Biomèdiques August Pi i Sunyer (IDIBAPS), Barcelona, Spain
| | - Dolors Soy
- Division of Medicines, Pharmacy Service, Hospital Clínic, Institut d'Investigacions Biomèdiques August Pi i Sunyer (IDIBAPS), University of Barcelona, Barcelona, Spain
| | - Lluïsa García-Esteve
- Perinatal Psychiatry Program, Department of Psychiatry and Psychology, Hospital Clínic, Institut d'Investigacions Biomèdiques August Pi i Sunyer (IDIBAPS), Barcelona, Spain.,Department of Medicine, University of Barcelona, Barcelona, Spain
| | - Rocio Martin-Santos
- Department of Medicine, University of Barcelona, Barcelona, Spain.,Department of Psychiatry and Psychology, Hospital Clinic, Institut d'Investigacions Biomèdiques Artur Pi i Sunyer (IDIBAPS), Centro de Investigación Biomédica en Red en Salud Mental (CIBERSAM), Barcelona, Spain
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Piwowarska J, Radziwoń-Zaleska M, Dmochowska M, Szepietowska E, Matsumoto H, Sygitowicz G, Pilc A, Łukaszkiewicz J. The usefulness of monitored therapy using Clozapine concentration in the blood serum for determining drug dose in Polish schizophrenic patients. Pharmacol Rep 2016; 68:1120-1125. [DOI: 10.1016/j.pharep.2016.06.016] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/15/2016] [Revised: 06/23/2016] [Accepted: 06/24/2016] [Indexed: 11/27/2022]
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Saracino MA, Lazzara G, Prugnoli B, Raggi MA. Rapid assays of clozapine and its metabolites in dried blood spots by liquid chromatography and microextraction by packed sorbent procedure. J Chromatogr A 2011; 1218:2153-9. [DOI: 10.1016/j.chroma.2011.01.071] [Citation(s) in RCA: 53] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/06/2010] [Revised: 01/20/2011] [Accepted: 01/21/2011] [Indexed: 11/16/2022]
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Rao LV, Snyder ML, Vallaro GM. Rapid liquid chromatography/tandem mass spectrometer (LCMS) method for clozapine and its metabolite N-desmethyl clozapine (norclozapine) in human serum. J Clin Lab Anal 2010; 23:394-8. [PMID: 19927349 DOI: 10.1002/jcla.20345] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022] Open
Abstract
Clozapine is indicated for the treatment of schizophrenia and related psychotic disorders. Several methods have been developed for monitoring Clozapine levels; however, they possess limited specificity and are often laborious. This study describes a simple liquid chromatography/tandem mass spectrometer (LCMS) method in human serum. The ion transitions monitored were m/z 327, 270, 296 for Clozapine, m/z 313, 192, 227 for Norclozapine and m/z 328, 271 for Loxapine. The assay is linear (25-1000 ng/ml) and showed a good correlation (r=0.98) within the analytical range of 79-1210 ng/ml in human serum. This assay is highly specific and sensitive for the simultaneous measurements of Clozapine and Norclozapine. The simplification of this assay makes it ideal for high throughput analyses of the patient samples in a routine clinical laboratory staffed with general medical technologists.
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Affiliation(s)
- L V Rao
- Department of Hospital Laboratories, UMassMemorial Medical Center, Worcester, Massachusetts 01605, USA.
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Darwish I, Abdel-Wadood H, Abdel-Latif N. Validated spectrophotometric and fluorimetric methods for analysis of clozapine in tablets and urine. ACTA ACUST UNITED AC 2006; 95:345-56. [PMID: 16477942 DOI: 10.1002/adic.200590039] [Citation(s) in RCA: 16] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
Abstract
Five spectrophotometric methods and one fluorimetric method have been developed and validated for the analysis of clozapine. The spectrophotometric methods were based on the charge-transfer complexation reaction between clozapine as electron donor and each of iodine as sigma-acceptor or 7,7,8,8-tetracyanoquinondimethane (TCNQ), 2,3-dichloro-5,6-dicyano-1,4-benzo-quinone (DDQ), tetracyanoethane (TCNE), and p-chloranilic acid (pCA) as pi-acceptors. The obtained complexes were measured spectrophotometrically at 365, 843, 460, 414, and 520 nm for iodine, TCNQ, DDQ, TCNE, and pCA, respectively. The fluorimetric method was based on the oxidation of clozapine in the presence of perchloric acid by cerium (IV), and subsequent measuring the fluorescence of the produced cerium (III) fluorimetrically at lambda(excitation) 260 and lambda(emission) 355 nm. Under the optimum assay conditions, Beer's law was obeyed at concentrations ranged from 4-200 microg mL(-1) for the spectrophotometric methods and from 24-250 ng mL(-1) for the fluorimetric method. The limits of detection for the spectrophotometric methods were 1.12, 1.76, 2.22, 0.95, and 13.26 microg mL(-1) for iodine, TCNQ, DDQ, TCNE, and pCA, respectively. The limit of detection for the fluorimetric method was 6.69 ng mL(-1). The proposed methods were successfully applied to the analysis of clozapine in tablets with good recoveries. The fluorimetric method could also be applied to the analysis of clozapine in spiked urine samples. The molar ratios and the reaction mechanisms were investigated.
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Affiliation(s)
- Ibrahim Darwish
- Department of Pharmaceutical Analytical Chemistry, Faculty of Pharmacy, Assiut University, Assiut 71526, Egypt.
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Niederländer HAG, Koster EHM, Hilhorst MJ, Metting HJ, Eilders M, Ooms B, de Jong GJ. High throughput therapeutic drug monitoring of clozapine and metabolites in serum by on-line coupling of solid phase extraction with liquid chromatography–mass spectrometry. J Chromatogr B Analyt Technol Biomed Life Sci 2006; 834:98-107. [PMID: 16527550 DOI: 10.1016/j.jchromb.2006.02.042] [Citation(s) in RCA: 49] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/19/2005] [Revised: 02/03/2006] [Accepted: 02/17/2006] [Indexed: 11/24/2022]
Abstract
The characteristics of automated on-line solid phase extraction with liquid chromatography-mass spectrometry (SPE-LC-MS) are very amenable for flexibility and throughput in therapeutic drug monitoring (TDM). We demonstrate this concept of automated, on-line SPE-LC-MS for the analysis of clozapine and metabolites (desmethylclozapine and clozapine-N-oxide) in serum. Method development, optimisation and validation are described and a comparison with previously published methods for the determination of clozapine and metabolites in serum and plasma is made. Optimisation of chromatographic and SPE conditions for increased throughput resulted in SPE-LC-MS cycle times of only about 2.2 min, demonstrating the great potential of automated on-line SPE-LC-MS for TDM. The new method is shown to be clearly favourable, in particular in terms of ease of sample handling, throughput and detection limits. Recovery is essentially quantitative. Detection limits are at about 0.15-0.3 ng ml(-1), depending on the ionisation source used. Calibration follows a quadratic model for clozapine and its N-oxide and a linear model for the desmethyl metabolite (all cases: R > 0.99). Accuracy, evaluated at three concentration levels spanning the whole therapeutic range, shows that bias is less than 10%. Precision (intra - and inter assay) ranges from about 5% R.S.D. at the high end of the therapeutic range (700-1,000 ng ml(-1)) to about 20% R.S.D. (OECD defined limit) at the lower limit of quantitation ( approximately 50 ng ml(-1)). The lower limit of quantitation is well below the low end of the therapeutic range at 350 ng ml(-1).
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Affiliation(s)
- H A G Niederländer
- Pharmaceutical Analysis Group, University Center of Pharmacy, A. Deusinglaan 1, 9713 AV Groningen, The Netherlands
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11
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Zhou Z, Li X, Li K, Xie Z, Cheng Z, Peng W, Wang F, Zhu R, Li H. Simultaneous determination of clozapine, olanzapine, risperidone and quetiapine in plasma by high-performance liquid chromatography-electrospray ionization mass spectrometry. J Chromatogr B Analyt Technol Biomed Life Sci 2004; 802:257-62. [PMID: 15018785 DOI: 10.1016/j.jchromb.2003.11.037] [Citation(s) in RCA: 89] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/19/2003] [Revised: 11/24/2003] [Accepted: 11/24/2003] [Indexed: 10/26/2022]
Abstract
UNLABELLED Clozapine (CLZ), olanzapine (OLZ), risperidone (RIP) and quetiapine (QTP) have been widely used in the treatment of schizophrenia. However, no study (or little study) has been conducted to determine the four drugs simultaneously by the use of high-performance liquid chromatography-electrospray ionization mass spectrometry (HPLC-MS/ESI). OBJECTIVE To develop a sensitive method for simultaneous determination of CLZ, OLZ, RIP and QTP in human plasma by HPLC-MS/ESI. METHODS The analytes were extracted twice by ether after samples had been alkalinized. The HPLC separation of the analytes was performed on a MACHEREY-NAGEL C(18) (2.0 mm x 125 mm, 3 microm, Germany) column, using water (formic acid: 2.70 mmol/l, ammonium acetate: 10 mmol/l)-acetonitrile (53:47) as mobile phase, with a flow-rate of 0.16 ml/min. The compounds were ionized in the electrospray ionization (ESI) ion source of the mass spectrometer and were detected in the selected ion recording (SIR) mode. RESULTS The calibration curves were linear in the ranges of 20-1000 ng/ml for CLZ and QTP, 1-50 ng/ml for OLZ and RIP, respectively. The average extraction recoveries for all the four analysts were at least above 80%. The methodology recoveries were higher than 91% for the analysts. The intra- and inter-day R.S.D. were less than 15%. CONCLUSION The method is accurate, sensitive and simple for routine therapeutic drug monitoring (TDM) and for the study of the pharmacokinetics of the four drugs.
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Affiliation(s)
- Zhiling Zhou
- Clinical Pharmaceutical Research Institute of Second Xiangya Hospital of Central South University, Changsha 410011, PR China
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Doude van Troostwijk LJAE, Koopmans RP, Vermeulen HDB, Guchelaar HJ. CYP1A2 activity is an important determinant of clozapine dosage in schizophrenic patients. Eur J Pharm Sci 2004; 20:451-7. [PMID: 14659489 DOI: 10.1016/j.ejps.2003.09.010] [Citation(s) in RCA: 44] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
Clozapine is an effective atypical antipsychotic drug applied in the treatment of resistant schizophrenia. The drug is mainly metabolized by cytochrome P-450 (CYP) enzymes especially the isozyme CYP1A2. Remarkably, the effective dosage varies widely among patients, making it necessary to individualize drug therapy with clozapine. The explanation for dosage variation may be differences in drug metabolism, and more specifically of CYP1A2 activity. This study is aimed at determining to what extent variability in clozapine dose can be explained by pharmacokinetic (PK) factors and more specifically by CYP1A2 activity in effectively treated psychiatric patients. In 22 evaluable patients with a schizophrenic disorder chronically using clozapine, the CYP1A2 activity and the clozapine clearance were estimated. For calculation of the pharmacokinetic parameters of clozapine, population PK software based upon Bayesian analysis was used. Caffeine clearance was estimated with the paraxanthine/caffeine ratio and served as estimate of CYP1A2 activity.A significant linear relationship was found between the clozapine dose and clozapine clearance (R: 0.71; P<0.05), whereas no relationship was found between clozapine dosage and clozapine serum trough concentration. Moreover, individual caffeine and clozapine clearances were found to be significantly related (R: 0.62; P<0.05) as were clozapine dose per kg body weight and P/C mol ratio (R: 0.44; P<0.05). We conclude that CYP1A2 activity is an important determinant of the variability of effective clozapine doses in psychiatric patients.
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Affiliation(s)
- Lous J A E Doude van Troostwijk
- Department of Clinical Pharmacy, Academic Medical Centre, University of Amsterdam, Meibergdreef 9, NL 1105 AZ Amsterdam, The Netherlands
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Hammam E, Tawfik A, Ghoneim MM. Adsorptive stripping voltammetric quantification of the antipsychotic drug clozapine in bulk form, pharmaceutical formulation and human serum at a mercury electrode. J Pharm Biomed Anal 2004; 36:149-56. [PMID: 15351059 DOI: 10.1016/j.jpba.2004.04.012] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/22/2004] [Revised: 04/20/2004] [Accepted: 04/25/2004] [Indexed: 12/01/2022]
Abstract
Using the cyclic voltammetry technique and the Britton-Robinson buffer (pH 2-10) as a supporting electrolyte, clozapine was found to reduce at the hanging mercury drop electrode in a single two-electron irreversible step corresponding to reduction of the azomethine group of the seven-member heterocyclic ring. Based on the interfacial adsorptive character of clozapine onto the hanging mercury drop electrode, a validated square-wave adsorptive cathodic stripping (SWAdCS) voltammetric procedure was described for the quantification of bulk clozapine with limits of detection and quantitation of 4.5 x 10(-10) and 1.5 x 10(-9) M, respectively. The proposed procedure was successfully applied to the quantification of the drug in pharmaceutical formulation (Leponex) and human serum without the necessity for samples' pretreatment or any time-consuming extraction or evaporation steps prior to the analysis. The limits of detection and quantitation of clozapine in spiked human serum were found to be 1 x 10(-9) and 3.3 x 10(-9) M, respectively. The proposed procedure for quantification of clozapine in bulk form, tablets and human serum has the advantage of being simple, rapid, sensitive, precise and inexpensive compared to most of the reported methods.
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Affiliation(s)
- E Hammam
- Chemistry Department, Faculty of Science, Tanta University, 31527 Tanta, Egypt.
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Mosier KE, Song J, McKay G, Hubbard JW, Fang J. Determination of clozapine, and its metabolites, N-desmethylclozapine and clozapine N-oxide in dog plasma using high-performance liquid chromatography. J Chromatogr B Analyt Technol Biomed Life Sci 2003; 783:377-82. [PMID: 12482480 DOI: 10.1016/s1570-0232(02)00655-4] [Citation(s) in RCA: 19] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
Abstract
Clozapine and its two major metabolites, N-desmethylclozapine and clozapine N-oxide were quantified using a high-performance liquid chromatographic method with UV detection in dog plasma following a single dose of clozapine. The analysis was performed on a 5-micrometer Hypersil CN (CPS-1; 250x4.6 mm) column. The mobile phase consisted of acetonitrile-water-1 M ammonium acetate (50:49:1, v/v/v), which was adjusted to pH 5.0 with acetic acid. The detection wavelength was 254 nm. A liquid-liquid extraction technique was used to extract clozapine and its metabolites from dog plasma. The recovery rates for clozapine, N-desmethylclozapine, and the internal standard (I.S.) were close to 100% using this method. The recovery rate for clozapine N-oxide (62-66%) was lower as expected because it is more polar. The quantitation limits for clozapine, clozapine N-oxide, and N-desmethylclozapine were 0.11, 0.05 and 0.05 microM, respectively. Intra-day reproducibility for concentrations of 0.1, 1.0 and 5.0 microM were 10.0, 4.4 and 4.2%, respectively, for N-oxide; 11.2, 4.3 and 4.9%, respectively, for N-desmethylclozapine; and 10.8, 2.2 and 4.9%, respectively, for clozapine. Inter-day reproducibility was <15% for clozapine N-oxide, <8% for N-desmethylclozapine and <19% for clozapine. This simple method was applied to determine the plasma concentration profiles of clozapine, N-desmethylclozapine and clozapine N-oxide in dog following administration of a 10 mg/kg oral dose of clozapine.
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Affiliation(s)
- Karen E Mosier
- College of Pharmacy and Nutrition, 110 Science Place, University of Saskatchewan, Saskatchewan S7N 5C9, Saskatoon, Canada
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Kollroser M, Schober C. Direct-injection high performance liquid chromatography ion trap mass spectrometry for the quantitative determination of olanzapine, clozapine and N-desmethylclozapine in human plasma. RAPID COMMUNICATIONS IN MASS SPECTROMETRY : RCM 2002; 16:1266-1272. [PMID: 12112253 DOI: 10.1002/rcm.718] [Citation(s) in RCA: 42] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/23/2023]
Abstract
A specific and sensitive direct-injection high performance liquid chromatography electrospray ionization tandem mass spectrometry (HPLC/ESI-MS/MS) method has been developed for the rapid identification and quantitative determination of olanzapine, clozapine, and N-desmethylclozapine in human plasma. After the addition of the internal standard dibenzepin and dilution with 0.1% formic acid, plasma samples were injected into the LC/MS/MS system. Proteins and other large biomolecules were removed during an online sample cleanup using an extraction column (1 x 50 mm i.d., 30 microm) with a 100% aqueous mobile phase at a flow rate of 4 mL/min. The extraction column was subsequently brought inline with the analytical column by automatic valve switching. Analytes were separated on a 5 microm Symmetry C18 (Waters) analytical column (3.0 x 150 mm) with a mobile phase of acetonitrile/0.1% formic acid (20:80, v/v) at a flow rate of 0.5 mL/min. The total analysis time was 6 min per sample. The inter- and intra-assay coefficients of variation for all compounds were <11%. By eliminating the need for extensive sample preparation, the proposed method offers very large savings in total analysis time.
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Affiliation(s)
- Manfred Kollroser
- Institute of Forensic Medicine, Karl-Franzens University Graz, Universitaetsplatz 4/II, A8010 Graz, Austria.
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