ABSTRACT
A simple, reliable and sensitive liquid chromatography-isotope dilution mass spectrometry (LC-ID/MS) was developed and validated for quantification of olanzapine in human plasma. Plasma samples (50 microL) were extracted with tert-butyl methyl ether and isotope-labeled internal standard (olanzapine-D3) was used. The chromatographic separation was performed on XBridge Shield RP 18 (100 mm x 2.1 mm, 3.5 microm, Waters). An isocratic program was used at a flow rate of 0.4 m x min(-1) with mobile phase consisting of acetonitrile and ammonium buffer (pH 8). The protonated ions of analytes were detected in positive ionization by multiple reactions monitoring (MRM) mode. The plasma method, with a lower limit of quantification (LLOQ) of 0.1 ng x mL(-1), demonstrated good linearity over a range of 0.1 - 30 ng x mL(-1) of olanzapine. Specificity, linearity, accuracy, precision, recovery, matrix effect and stability were evaluated during method validation. The validated method was successfully applied to analyzing human plasma samples in bioavailability study.
Subject(s)
Humans , Antipsychotic Agents , Blood , Pharmacokinetics , Benzodiazepines , Blood , Pharmacokinetics , Biological Availability , Chromatography, Liquid , Methods , Indicator Dilution Techniques , Isotope Labeling , Reproducibility of Results , Sensitivity and Specificity , Tandem Mass Spectrometry , MethodsABSTRACT
<p><b>AIM</b>To establish an HPLC-fluorescent spectrometric method for the determination of mexiletine hydrochloride in plasma after derivatization with fluram.</p><p><b>METHODS</b>Fluram acetone solution was added to the deproteinized plasma with acetone to obtain the derivative of mexiletine. The HPLC method was performed on a column of Allitima C18 (150 mm x 4.6 mm, 5 microns) with the mobile phase of methanol-water-diethylamine-phosphoric acid buffer (2.4 mol.L-1, pH 4.0) (70:28:2), and the detective wavelength were set at Ex 392 nm and Em 480 nm.</p><p><b>RESULTS</b>Mexiletine has a liner range over the concentration range from 0.100-6.400 mg.L-1. The lowest detectable concentration of this method was 5 micrograms.L-1 (S/N > or = 4). The intra-day and inter-day RSDs were 1.34%-5.31%, respectively.</p><p><b>CONCLUSION</b>This method is simple, selective and can be used for therapeutic drug monitoring (TDM) and pharmacokinetic studies of mexiletine.</p>