A simple liquid-liquid extraction with hexane for low-picogram determination of drugs and their metabolites in plasma by high-performance liquid chromatography with positive ion electrospray tandem mass spectrometry.
Four sensitive, specific and accurate methods, based on high-performance liquid chromatography (HPLC) with positive ion electrospray tandem mass spectrometry (MS/MS) coupled with liquid-Liquid extraction (LLE), have been developed and validated for the low-picogram determination of two drug candidates and a metabolite (compounds I-III) in human, monkey and rat plasma. In the LLE procedure, hexane or a mixture of hexane and methyl t-butyl ether was used to isolate these compounds from plasma of the different species after basification of each biological sample with sodium carbonate. The reconstituted extracts were then injected into a positive ion electrospray LC/MS/MS system for the quantitative analysis. The lower limit of quantitation of the methods ranged from 20 to 200 pg/mL. The use of hexane for the LLE proved to be simple, rapid and reproducible, and provided very clean extracts with little interference. The inter- and intra-day precision for the four methods was within 9%, and the accuracy was in the range 94-107%. The effect of pH on the isomerization of I (E-isomer) to its Z-isomer (II) showed that the rate of isomerization increased with decrease in pH and that there was no isomerization at pH >/=6.
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Bioanalytical Research, Metabolism and Pharmacokinetics, Bristol-Myers Squibb Pharmaceutical Research Institute, P.O. Box 191, New Brunswick, NJ 08903-0191, USA.
Whigan
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DB
Jemal
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M
D000818:Animals; D002851:Chromatography, High Pressure Liquid / Q000379:methods* / Q000592:standards / Q000706:statistics & numerical data; D000882:Haplorhini; D006801:Humans; D013058:Mass Spectrometry / Q000379:methods* / Q000592:standards / Q000706:statistics & numerical data; D008832:Microchemistry; D004364:Pharmaceutical Preparations / Q000032:analysis* / Q000378:metabolism / Q000592:standards; D051381:Rats; D012015:Reference Standards; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity
D004364:Pharmaceutical Preparations