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dc.contributor.authorSanchez, S.
dc.contributor.authorJones, D.G.
dc.contributor.authorSmall, J.
dc.contributor.authorMcKellar, Quintin
dc.identifier.citationSanchez , S , Jones , D G , Small , J & McKellar , Q 2002 , ' Plasma achiral and chiral pharmacokinetic behaviour of intravenous oxfendazole co-administered with piperonyl butoxide in sheep ' , Journal of Veterinary Pharmacology and Therapeutics , vol. 25 , no. 1 , pp. 7-13 .
dc.identifier.otherPURE: 1409843
dc.identifier.otherPURE UUID: ac65de20-8880-43e5-8ec0-15a434a0352d
dc.identifier.otherBibtex: urn:1899ff6d8a1d63b2b73a7ff827136b04
dc.identifier.otherScopus: 0036274246
dc.description.abstractCo-administration of piperonyl butoxide (PB) potentiates fenbendazole (FBZ) in small ruminants. The resultant increase in bioavailability of FBZ and its metabolite oxfendazole (OFZ) has important implications for the efficacy of these drugs against benzimidazole (BZD)-resistant strains of Teladorsagia circumcincta. This study evaluated the racemic (achiral) and enantiomeric (chiral) plasma disposition kinetics of OFZ and its metabolites after the co-administration of PB and OFZ in sheep. Six 6-8-month-old, parasite-free, female Dorset sheep (30-40 kg) were used in a two-phase crossover experiment. In phase I, three sheep received 30 mg/kg PB orally, followed by a single intravenous (i.v.) injection of OFZ at 5 mg/kg. The other three animals were treated similarly except that 5 mL of water replaced PB. In phase 2, treatments for the two groups were reversed and were given 14 days after the initiation of phase I. Three analytes OFZ, FBZ and fenbendazole sulphone (FBZSO(2)) were recovered in plasma up to 48 h post-treatment in both experimental groups. Achiral and chiral pharmacokinetic (PK) profiles for OFZ, after the co-administration of PB, were characterized by a significantly greater area under the concentration-time curve (AUC) and a longer mean residence time (MRT). Chiral OFZ distribution ratios were comparable in both treatment groups. Piperonyl butoxide treatment markedly influenced the plasma PK profiles for FBZ and FBZSO(2) following OFZ administration. Production of FBZ was enhanced as reflected by increased (>60%) AUC, delayed T-max and a significantly delayed (>45%) elimination (t1/2(el)). Although AUC values for FBZSO(2) were not significantly different between groups, this metabolite was depleted more slowly from plasma (t1/2(el) > 60% and MRT > 42%) following PB treatment. This study demonstrated that PB co-administration is associated with an inhibition of OFZ biotransformation, as evidenced by the significantly higher plasma concentrations of OFZ and FBZ, and this could have important implications in terms of antiparasite therapy against BZD-resistant parasite strains.en
dc.relation.ispartofJournal of Veterinary Pharmacology and Therapeutics
dc.titlePlasma achiral and chiral pharmacokinetic behaviour of intravenous oxfendazole co-administered with piperonyl butoxide in sheepen
dc.contributor.institutionOffice of the Vice-Chancellor
dc.contributor.institutionVeterinary Science
dc.contributor.institutionGeography, Environment and Agriculture
dc.description.statusPeer reviewed
rioxxterms.typeJournal Article/Review

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