Phenytoin free fraction determination: comparison of an improved direct serum injection high-performance liquid chromatographic method to ultrafiltration coupled with fluorescence polarization immunoassay

B. J. Gurley, M. Marx, K. Olsen

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Recent developments in restricted-access media (RAM) liquid chromatography make the simultaneous determination of total and free phenytoin concentrations possible by direct injection of drug-containing serum samples. A comparison of phenytoin free fraction determination by ultrafiltration coupled with fluorescence polarization immunoassay (TDX) to an improved direct injection RAM-HPLC method is presented. Our improved method differs from those previously reported with regard to column type, mobile-phase composition, and column temperature. Replicate samples analyzed by each method yielded similar values for serum phenytoin free fraction.

Original languageEnglish (US)
Pages (from-to)358-364
Number of pages7
JournalJournal of Chromatography B: Biomedical Sciences and Applications
Issue number2
Publication statusPublished - Aug 18 1995


ASJC Scopus subject areas

  • Chemistry(all)

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