Abstract
A simple and sensitive liquid chromatography-tandem mass spectrometry method was developed and validated in human plasma for the simultaneous determination of aripiprazole (ARI) and its metabolite dehydro-aripiprazole (DARI); olanzapine (OLA), risperidone (RIS), paliperidone (PAL), quetiapine (QUE), clozapine (CLO) and caffeine (CAF). CAF is included to the method because it can have an influence on drug metabolism due to competitive inhibition. The above mentioned compounds and their isotope-labeled internal standards were extracted from 200 µL human plasma samples by both, effective phospholipids-eliminating three-step microelution-solid-phase extraction (µ-SPE) and protein precipitation (PPT) for comparison. A combination of formic acid (0.2%)-acetonitrile (pH 3.0; 65:35, v/v) was used as mobile phase and the chromatogram was run under gradient conditions at a flow rate of 0.6 mL/min. Run time lasted 6 min, followed by a re-equilibration time of 3 min. All analytes were monitored by mass spectrometric detection operating in multiple reaction monitoring mode and the method was validated covering the corresponding therapeutic ranges: 0.18–120 ng/mL for ARI, 0.25–80 ng/mL for DARI, 1.00–100 ng/mL for OLA, 0.70–60 ng/mL for RIS, 0.20–30 ng/mL for PAL, 0.50–160 ng/mL for QUE, 0.50–1000 ng/mL for CLO, and finally 1200–3700 ng/mL for CAF. The method was validated based on the recommendations of regulatory agencies through tests of precision, accuracy, extraction recovery, identity confirmation, trueness, matrix effect, process efficiency, stability, selectivity, linearity and carry-over effect fulfilling the guideline requirements. Our µ-SPE method results in the elimination of more than 99% of early eluting and more than 92% of late-eluting phospholipids compared to PPT. Additionally, the method was successfully applied for quantifying ARI and OLA plasma concentrations from healthy volunteers.
Highlights
Aripiprazole (ARI), olanzapine (OLA), risperidone (RIS), paliperidone (PAL; 9hydroxyrisperidone), quetiapine (QUE) and clozapine (CLO) are commonly used atypical antipsychotics with demonstrated efficacy in schizophrenia and bipolar disorder [1]
Experimental conditions in LC and mass spectrometry OLA (MS)/MS Due to the similar pKa values ranging from 7.06 to 8.76 [27], for all drugs included in this method, it was possible to optimize extraction method and validate an liquid chromatography-mass spectrometry LC-MS/MS (LC-MS)/MS method for simultaneous quantification of ARI, DARI, OLA, RIS, PAL, QUE, and CLO
Differences in water solubility ranging from 0.008 mg/mL to 0.297 mg/mL, except for CAF, which has very high water solubility of 11 mg/mL [27] enabled us to perform an excellent chromatographic separation
Summary
Aripiprazole (ARI), olanzapine (OLA), risperidone (RIS), paliperidone (PAL; 9hydroxyrisperidone), quetiapine (QUE) and clozapine (CLO) are commonly used atypical antipsychotics with demonstrated efficacy in schizophrenia and bipolar disorder [1]. PAL is a parent compound, and a metabolite of RIS [2] These denominated second generation antipsychotics are effective in the treatment of schizophrenia - including both positive and negative symptoms - and are less likely to produce extrapyramidal symptoms and tardive dyskinesia when compared to first generation antipsychotics [1]. These six drugs were included in the analysis based on their importance in the worldwide market. LCMS/MS allows to achieve shorter run times and better lower limits of quantification (LLOQs)
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