Simultaneous determination of four antipsychotic drugs in plasma by high-performance liquid chromatography

Development of a simultaneous LC-MS/MS analytical method for plasma: 16 antipsychotics approved in Japan and 4 drug metabolites

The increased risk of adverse drug reactions due to the concomitant use of antipsychotics is problematic in the treatment of schizophrenia. Therefore, the simultaneous analysis of their plasma concentrations is required. In this study, we developed a simultaneous liquid chromatography/tandem mass spectrometry (LC-MS/MS) method for analyzing plasma antipsychotics approved in Japan for therapeutic drug monitoring (TDM) applications. First, we counted the prescriptions for 16 antipsychotics and concomitant drugs used at the Tohoku University Hospital. LC-MS/MS was used for the simultaneous analysis of 16 antipsychotics and four drug metabolites. This analysis was conducted using a combination of selected reaction monitoring mode and reversed-phase chromatography. Following the examination of the MS/MS and LC conditions, an analytical method validation test was conducted. The developed method was used to analyze plasma antipsychotic levels in patients with schizophrenia. One-third of the patients received treatment with multiple antipsychotics. Under LC-MS/MS conditions, LC separation was performed using a combination of a C18 column and ammonium formate-based mobile phases with a gradient flow. The calibration curves were optimized by adjusting the ion abundance, and 11 compounds met the criteria for intra- and inter-day reproducibility tests. Some stability test results did not meet these criteria; therefore, further investigation is required. The developed method permitted the measurement of all the plasma parameters, including concentrations above the therapeutic range. Therefore, this method may be useful in the daily TDM practice of antipsychotics.

Determination of Chlorpromazine, Haloperidol, Levomepromazine, Olanzapine, Risperidone, and Sulpiride in Human Plasma by Liquid Chromatography/Tandem Mass Spectrometry (LC-MS/MS)

Background and Objective

In this study, turbo-ion spray as an interface of tandem mass spectrometry (MS/MS) was performed for sensitive and accurate quantification of chlorpromazine, haloperidol, levomepromazine, olanzapine, risperidone, and sulpiride in plasma samples.

Methods

Separation was performed by gradient reversed phase high-performance liquid chromatography using a mobile phase containing ammonium formiate 2 mM, pH 2.7, and acetonitrile flowing through a Restek PFP Propyl C18 analytical column (50 mm×2.1 mm i.d.) with particle size of 5 µm, at a flow rate of 800 µL/min. Positive ion fragments were detected in multiple reaction monitoring (MRM) mode. Sample preparation was achieved by solid phase extraction (SPE) (Oasis HLB).

Results

Mean extraction recoveries ranged from 82.75% to 100.96%. The standard calibration curves showed an excellent linearity, covering subtherapeutic, therapeutic, and toxic ranges. Intraday and interday validation using quality control (QC) samples were performed. The inaccuracy and imprecision were below 12% at all concentration levels. The limits of detection (LOD) and quantification (LOQ) for all analytes were under therapeutic ranges for all tested analytes. Thus, the proposed method was sensitive enough for the detection and determination of subtherapeutic levels of these antipsychotics in plasma samples. No interference of endogenous or exogenous molecules was observed and no carryover effects were recorded.

Conclusion

According to the results, the proposed method is simple, specific, linear, accurate, and precise and can be applied for antipsychotic analysis in clinical routine. This method was applied for the determination of the tested antipsychotics in plasma samples taken from 71 individuals.

Therapeutic drug monitoring of common antipsychotics

The aim of this review is to provide information for interpreting outcome results from monitoring of antipsychotics in biological samples. A brief overview of the working mechanisms, pharmacological effects, drug interactions, and analytical methods of classical and atypical antipsychotics is given. Nineteen antipsychotics were selected based on their importance in the worldwide market as follows: amisulpride, aripiprazole, asenapine, bromperidol, clozapine, flupenthixol, haloperidol, iloperidone, lurasidone, olanzapine, paliperidone, perphenazine, pimozide, pipamperone, quetiapine, risperidone, sertindole, sulpiride, and zuclopenthixol. A straightforward relationship between administered dose, plasma or serum concentration, clinical outcome, or adverse effects is often lacking. Nowadays, focus lies on therapeutic drug monitoring and individualized therapy to find adequate treatment, to explain treatment failure or nonresponse, and to check patient compliance. However, extensive research in this field is still mandatory.

Development of a method of clozapine dosage by selective electrode to the iodides

Clozapine (Leponex(®)), the main neuroleptic indicated in the treatment of resistant schizophrenia, requires therapeutic monitoring because of its side effects and the individual variability in metabolism. In addition, several cases of intoxication by this drug were described in the literature. In this work, we studied the indirect dosage of clozapine by selective electrode to the iodides for the optimization of an analytical protocol allowing therapeutic monitoring and the diagnosis of intoxication and/or overdose. Our results showed that the developed method is linear between 0.05 and 12.5 µg/mL (r = 0.980), with a limit of detection of 0.645.10(-3) µg/mL. It presents good precision (coefficient of variation less than 4%) and accuracy (coefficient less than 10%) for all the studied concentrations. With a domain of linearity covering a wide margin of concentrations, this method can be applicable to the dosage of clozapine in tablets and in different biological matrices, such as plasma, urines, and postmortem samples.

Simultaneous determination of five antipsychotic drugs in rat plasma by high performance liquid chromatography with ultraviolet detection

A significant percentage of psychiatric patients who are treated with antipsychotics are treated with more than one antipsychotic drug in the clinic. Thus, it is advantageous to use a rapid and reliable assay that is suitable for determination of multiple antipsychotic drugs in plasma in a single run. A simple and sensitive HPLC-UV method was developed and validated for simultaneous quantification of olanzapine, haloperidol, chlorpromazine, ziprasidone, risperidone and its active metabolite 9-hydroxyrisperidone in rat plasma using imipramine as an internal standard (I.S.). The analytes were extracted from rat plasma using a single step liquid-liquid acid solution back extraction technique with wash procedure, which provided the very clear baseline for blank plasma extraction. The compounds were separated on an Agilent Eclipse XDB C8 (150 mm x 4.6 mm i.d., 5 microm) column using a mobile phase of acetonitrile/30 mM ammonium acetate including 0.05% triethylamine (pH 5.86 adjusted with acetic acid) with gradient elution. All of the analytes were monitored using UV detection. The method was validated and the linearity, lower limit of quantitation (LLOQ), precision, accuracy, recoveries, selectivity and stability were determined. The LLOQ was 2.0 ng/ml and correlation coefficient (R(2)) values for the linear range of 2.0-500.0 ng/ml were 0.998 or greater for all the analytes. The precision and accuracy for intra-day and inter-day were better than 7.44%. The recovery was above 74.8% for all of the analytes. This validated method has been successfully used to quantify the plasma concentration of the analytes for pharmacological and toxicological studies following chronic treatment with antipsychotic drugs in the rat.

Simultaneous analysis of classical neuroleptics, atypical antipsychotics and their metabolites in human plasma

A high-performance liquid chromatographic method has been developed for the simultaneous determination of classical neuroleptics (chlorpromazine, haloperidol, loxapine and clotiapine), atypical antipsychotics (clozapine, quetiapine and risperidone) and their active metabolites (N-desmethylclozapine, clozapine N-oxide and 9-hydroxyrisperidone) in human plasma. Separation was obtained by using a C8 reversed-phase column and a mobile phase composed of 70% aqueous phosphate buffer containing triethylamine at pH 3.0 and 30% acetonitrile. The UV detector was set at 238 nm and amitriptyline was used as the internal standard. A careful pre-treatment procedure of plasma samples was developed, using solid-phase extraction with cyanopropyl cartridges, which gives high extraction yields (>or=93%). The limits of quantitation (LOQ) were always lower than 2.6 ng mL-1 and the limits of detection (LOD) were always lower than 0.9 ng mL-1 for all analytes. The method was applied with success to plasma samples from schizophrenic patients undergoing polypharmacy with two or more different antipsychotics. Precision data and accuracy results were satisfactory and no interference from other central nervous system (CNS) drugs was found. Hence the method is suitable for the therapeutic drug monitoring (TDM) of the analytes in psychotic patients' plasma.

Liquid chromatography/tandem mass spectrometry method for the simultaneous determination of olanzapine, risperidone, 9-hydroxyrisperidone, clozapine, haloperidol and ziprasidone in rat plasma

A simple, sensitive and rapid liquid chromatography/electrospray ionization tandem mass spectrometry (LC/ESI-MS/MS) method was developed and validated for simultaneous quantification of olanzapine, clozapine, ziprasidone, haloperidol, risperidone, and its active metabolite 9-hydroxyrisperidone, in rat plasma using midazolam as internal standard (IS). The analytes were extracted from rat plasma using a single step liquid-liquid extraction technique. The compounds were separated on a Waters Atlantis dC-18 (30 mm x 2.1 mm i.d., 3 microm) column using a mobile phase of acetonitrile/5 mM ammonium formate (pH 6.1 adjusted with formic acid) with gradient elution. All of the analytes were detected in positive ion mode using multiple reaction monitoring (MRM). The method was validated and the specificity, linearity, lower limit of quantitation (LLOQ), precision, accuracy, recoveries and stability were determined. LLOQ was 0.1 ng/mL and correlation coefficient (R(2)) values for the linear range of 0.1-100 ng/mL were 0.997 or greater for all the analytes. The intra-day and inter-day precision and accuracy were better than 8.05%. The relative and absolute recovery was above 77% and matrix effects were low for all the analytes except for ziprasidone. This validated method has been successfully used to quantify the plasma concentration of the analytes after chronic treatment with antipsychotic drugs.

Spectrophotometric determination of clozapine based on its oxidation with bromate in a micellar medium

A simple and sensitive spectrophotometric method was developed for the determination of clozapine in its dosage forms. The method is based on the reaction of the drug with potassium bromate in a perchloric acid medium to produce an intense yellow colored species exhibiting a maximum absorption at 308 nm. Beer's law is obeyed for up to 12.0 microg ml(-1) with a correlation coefficient (n = 6) of 0.9998 and a detection limit (3S(b)) of 0.1 microg ml(-1). The molar absorptivity is 1.986 x 10(4) l mol(-1) cm(-1). The various experimental parameters affecting the development and stability of the colored oxidation product were carefully studied and optimized. The proposed method was successfully applied to the determination of clozapine in its dosage forms. The results obtained were in good agreement with those obtained using the B.P. official method.