Pharmacokinetic studies of the herbicide and antitumor compound oryzalin in mice

Katerina Dvorakova, Robert T. Dorr, Alfred Gallegos, Thomas McClure, Garth Powis

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8 Scopus citations


Oryzalin [3,5-dinitro-N,N-di(n-propyl)benzensulfanilamide] is a widely used sulfonamide herbicide that selectively inhibits microtubule formation in algae and higher plants. Oryzalin has also been found to be an inhibitor of intracellular free Ca2+ signalling in mammalian cells and to have antitumor activity in animals. Despite its widespread use there have been no reports of the pharmacokinetics of oryzalin in animals or man. A reversed-phase high-performance liquid chromatographic (HPLC) method was developed to measure oryzalin in biological fluids. Following repeated daily administration of oryzalin to mice by the i.p. route at 200 mg/kg, or the p.o. route at 300 mg/kg, peak plasma concentrations of up to 25 μg/ml were achieved. The half life for oryzalin in plasma of mice given i.p. oryzalin was 14.3 h with a clearance of 0.07 l/h. A major metabolite of oryzalin, N-depropyloryzalin, was identified in plasma and its structure confirmed by mass spectral analysis (M+H+=305). This metabolite was cleared more rapidly than oryzalin with a half life of 1.15 h and a clearance of 0.17 l/h. N-Depropyloryzalin caused similar inhibition of colony formation by HT-29 colon cancer cells as oryzalin with IC50=8 μg/ml. The results suggest that oryzalin and its N-depropyl metabolite can inhibit tumor colony formation at pharmacologically achievable levels.

Original languageEnglish (US)
Pages (from-to)275-281
Number of pages7
JournalJournal of Chromatography B: Biomedical Applications
Issue number2
StatePublished - Aug 29 1997


  • Oryzalin

ASJC Scopus subject areas

  • Chemistry(all)


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