Determination of lumefantrine in small-volume human plasma by LC-MS/MS: using a deuterated lumefantrine to overcome matrix effect and ionization saturation.

Drug Research Unit, Department of Clinical Pharmacy, School of Pharmacy, University of California, San Francisco, CA 94110, USA.
Bioanalysis (Impact Factor: 3.03). 01/2012; 4(2):157-66. DOI: 10.4155/bio.11.303
Source: PubMed

ABSTRACT To support pediatric study, a method to determine lumefantrine (LF) with small sample volume is needed. Matrix effect (ME) is a daunting issue in LF quantification in human plasma with LC-MS/MS.
Here we report an LC-MS/MS method with a deuterated LF as the internal standard (IS). Plasma sample (25 µl) was acidified with 5% formic acid prior to extraction with ethyl acetate. The recovery was over 80%. The absolute ME was within the range of 100 ± 8% for both LF and the IS, but cumulative ME was observed via large variation of IS signal. The cumulative ME and ionization saturation were overcome with the co-eluting LF-D(9) as the IS. The linear range of calibration curve was 50-20,000 ng/ml.
ME and ionization saturation was overcome with a deuterated IS. The method utilized a small sample volume, suitable for pediatric study with capillary tube blood collection method.

Download full-text


Available from: Liusheng Huang, Jun 22, 2015
  • [Show abstract] [Hide abstract]
    ABSTRACT: Determination of piperaquine (PQ) in pediatric plasma requires a method with a small sample volume. We report a sensitive LC-MS/MS method for quantitation of PQ with only 25 µl human plasma. Using a deuterated internal standard (PQ-d6), an analytical PFP column, APCI(+) as the ion source and MRM (535/288 for PQ and 541/294 for the IS) for detection, the method has a linear calibration range of 1.5-250 ng/ml with a runtime of 3.0 min per sample. The method was applied to plasma samples from children. The developed LC-MS/MS method is suitable for pediatric studies with small volume plasma samples collected via capillary tubes. One limitation was the performance of PFP columns varied among different brands.
    Bioanalysis 12/2014; 6(23):3081-9. DOI:10.4155/bio.14.254 · 3.03 Impact Factor
  • Source
    [Show abstract] [Hide abstract]
    ABSTRACT: The present paper reports the development of novel, stable & validated RP HPLC method for the simultaneousestimation of Artemether (ART) and lumefantrine (LUM) in bulk and tablet dosage form. Good chromatographic separationwas achieved by isocratic mode with a mixture of phosphate buffer: methanol in the ratio of 50: 50 as the mobile phase with waters symmetry Shield Rp18Column (250 mm x 4.6mm x 5) μm as stationary phase at a flow rate of 1.0 ml/min. The detection was performed at 273 nm. Retention time for LUM and ART were found 2.249 and 4.516 min respectively.The proposed method showed good intra-day precision (%RSD=0.068for ART, 0.033 for LUM), good accuracy (recovery for both ART and LUM >99% ), and high correlation coefficient(R2= 0.999 both ATM and LUM). The detectionand quantitation limits were 0.55 μg/ml and 1.35 μg/ml for ART and 0.09 μg/ml and 0.32 μg/ml for LUM. Thismethod found to have a good percentage recovery in a forced degradation study using acid, base, oxidation, photolytic,thermal and neutral conditions indicates well separation of both the drugs with other degradation products and the present method has shown good solution stability. Hence, the present study reports ever developed stability indicating easiest method which is useful for the routine analysis.
    Current Pharmaceutical Analysis 06/2014; 10(4). · 0.77 Impact Factor
  • [Show abstract] [Hide abstract]
    ABSTRACT: A liquid chromatography–tandem mass spectrometry (LC–MS/MS) method was developed and validated for the quantitation of the antimalarial drug, lumefantrine (LF), in mouse whole blood and plasma. The analyte was extracted using a protein precipitation method followed by chromatographic separation on a Phenomenex Luna, PFP (50 mm × 2.0 mm, 5 μm) analytical column with a mobile phase consisting of acetonitrile and 0.1% formic acid (formic acid:water, 1:1000, v/v) at a ratio of 3:7 (v/v), delivered at a constant flow rate of 0.5 ml/min. Stable isotope labeled lumefantrine (D9-LF) was used as the internal standard. Multiple reaction monitoring was performed using the transitions m/z 530.1 → m/z 347.9 and m/z 539.1 → m/z 347.9 for the quantification of LF and D9-LF, respectively. Calibration curves were constructed over the concentration range 15.6–4000 ng/ml. The mean intra- and inter-assay accuracy values for the analysis of LF in WB was 103% (%CV = 5.5) and 99.5% (%CV = 5.5), respectively. The mean intra- and inter-assay accuracy values for the analysis of LF in plasma was 93.7% (%CV = 3.5) and 93.9% (%CV = 5.5), respectively. No significant matrix effect was observed during the method validation. The validated method was applied to an absorption study in mice, to determine and compare LF concentrations in whole blood and plasma samples. Results of the statistical analysis using a linear mixed effects growth curve model concluded that there was no significant difference (p-value = 0.668) between WB and plasma LF concentrations. This method utilizes a small sample volume of 20 μl, facilitating low blood collection volumes and a short chromatographic run time of 3 min which allows for high sample throughput analysis.
    Journal of Chromatography B 03/2015; 985. DOI:10.1016/j.jchromb.2015.01.015 · 2.69 Impact Factor