Chiral determination of mirtazapine in human blood plasma by high-performance liquid chromatography
ABSTRACT A method is described for the determination of the two enantiomers of mirtazapine in human blood plasma by high-performance liquid chromatography. Measurements were performed on drug free plasma spiked with mirtazapine and used to prepare and validate standard curves. Levels of enantiomers of mirtazapine were also measured in patients being treated for depression with racemic mirtazapine. Mirtazapine was separated from plasma by solid-phase extraction using CERTIFY columns. Chromatographic separation was achieved using a Chiralpak AD column and pre-column and compounds were detected by their absorption at 290 nm. Imipramine was used as an internal standard. The assay was validated for each analyte in the concentration range 10–100 ng/ml. The coefficient of variance was 16% and 5.5% for(+)-mirtazapine for 10 and 100 ng/ml control specimens respectively and 15% and 7.3% for mirtazapine for 10 and 100 ng/ml control specimens respectively. This assay is appropriate for use in the clinical range. The range of plasma mirtazapine concentrations from eleven patients taking daily doses of 30–45 mg of racemate was <5 to 69 ng/ml for (+)-mirtazapine and 13–88 ng/ml for (−)-mirtazapine for blood specimens collected 10–17.5 h after taking the dose.
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ABSTRACT: High-performance liquid chromatographic methods were developed for separation of the enantiomers of mirtazapine and its four process-related substances. The direct separations were achieved on chiral stationary phases containing amylose tris(3,5-dimethylphenylcarbamate) (Chiralpak AD-H), cellulose tris(3,5-dimethylphenylcarbamate) (Chiralcel OD-H) and cellulose tris(4-methylbenzoate) (Chiralcel OJ-H ). The experimental data were utilized to discuss the effects of the mobile phase composition, the nature of the alcoholic modifier and the specific structural features of the analytes on retention and separation. The elution sequence was determined under the optimized separation conditions.Biomedical Chromatography 02/2012; 26(2):142-6. DOI:10.1002/bmc.1638 · 1.66 Impact Factor
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ABSTRACT: The metabolism of mirtazapine enantiomers was investigated in vitro using human lymphoblast microsomes transfected with human cDNA to overexpress either CYP1A2, CYP2C9, CYP2C19, CYP2D6 or CYP3A4 and assayed for mirtazapine enantiomers using a validated chiral method of high-performance liquid chromatography. (+)-Mirtazapine was extensively metabolised by CYP2D6 (K(m) = 9.3 +/- 3.3 &mgr;mol/l, V(max) = 40.9 +/- 7.9 &mgr;mol/h/mg, intrinsic clearance = 4.41 l/h/mg). CYP1A2 and CYP3A4 showed low metabolic activity towards (+)-mirtazapine and (-)-mirtazapine respectively. Neither CYP2C9 nor CYP2C19 appeared to be involved in the metabolism of the enantiomers of mirtazapine. Copyright 2001 John Wiley & Sons, Ltd.Human Psychopharmacology Clinical and Experimental 10/2001; 16(7):541-544. DOI:10.1002/hup.328 · 1.85 Impact Factor
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ABSTRACT: Some recent applications of stereoselective chromatography in the fields of clinical pharmacy, drug analysis, food, and natural products are reviewed. The review is documented with up-to-date literature, which will assist further expansion of research in these areas.Chirality 01/2002; 14(5):417-35. DOI:10.1002/chir.10110 · 1.72 Impact Factor