Stereoselective determination of methadone and the primary metabolite EDDP in human plasma by automated on-line extraction and liquid chromatography mass spectrometry.

Journal Article (Journal Article)

A sensitive stereoselective bioanalytical liquid chromatographic assay with mass spectrometric detection (LC-MS) was developed and validated for the on-line extraction and quantification of R- and S-methadone and the primary metabolite R- and S-2-ethylidene-1,5-dimethyl-3,3-diphenylpyrrolidine (EDDP) from human plasma. Deproteinized plasma was injected directly onto a small C8 column, washed and then back-flushed using a column switching valve and a second pump onto an alpha1-acid glycoprotein analytical column, and enantioselective separation achieved using a mobile phase gradient of methanol and ammonium formate. Analytes were validated over a range of 0.1-25 ng/ml R- and S-EDDP and 0.1-100ng/ml R- and S-methadone, respectively. Unweighted standard curves were linear over this concentration range (regression coefficients > 0.999). Quality control samples were evaluated at 1, 5, 12.5 ng/ml R- and S-EDDP and 1, 10, 50 ng/ml R- and S-methadone. Intra- and inter-day accuracy was >95%, and intra- and inter-day coefficients of variation were less than 10% for all analytes and concentrations. This assay represents the only method currently available which combines on-line extraction and achieves chiral separation of both methadone and EDDP from plasma, and offers improvements in sensitivity over existing methods.

Full Text

Duke Authors

Cited Authors

  • Whittington, D; Sheffels, P; Kharasch, ED

Published Date

  • October 5, 2004

Published In

Volume / Issue

  • 809 / 2

Start / End Page

  • 313 - 321

PubMed ID

  • 15315782

Pubmed Central ID

  • 15315782

International Standard Serial Number (ISSN)

  • 1570-0232

Digital Object Identifier (DOI)

  • 10.1016/j.jchromb.2004.06.041


  • eng

Conference Location

  • Netherlands