Kinetic disposition of triclabendazole in buffalo compared to cattle

Concentrations of triclabendazole sulfoxide and its sulfone metabolite in plasma were measured in buffalo and cross-bred cattle after single intraruminal administration of triclabendazole at two different doses. Plasma concentrations of both metabolites were significantly lower in buffalo than cattle at both doses, which resulted in a smaller area under the concentration-time curve, a lower concentration maximum and a lower relative bioavailability. Thus, the recommended doses of 12 mg/kg body weight for the treatment of bubaline fascloliasis may not be valid for buffalo because of the substantially lower uptake of the drug in this species.     

Effects of surfactants on primisulfuron activity in barnyardgrass (Echinochloa crus-galli [L.] Beauv.) and green foxtail (Setaria viridis [L.] Beauv.)

Laboratory and greenhouse studies were conducted to measure the contact angle of primisulfuron droplets with and without surfactants on the leaf surfaces of barnyardgrass and green foxtail, to determine the primisulfuron activity on these weed species, and to examine the spray deposit of primisulfuron with and without surfactants on the leaf surface of green foxtail using scanning electron microscopy. A non-ionic surfactant (NIS) and an organosilicone wetting agent (OWA) were used. The contact angles of 1 μL droplets were measured on the leaf surface using a goniometer. The activity of primisulfuron on barnyardgrass and green foxtail was assessed at 3 weeks after treatment based on visual injury and the fresh weight. The contact angles of the droplets of primisulfuron on the adaxial surface of the barnyardgrass and green foxtail leaves were 152° and 127°, respectively, when applied without surfactant. The addition of either surfactant markedly reduced the contact angle for both weed species, which was lowest when the OWA was added to primisulfuron. The percentage injury of barnyardgrass was very low, even at the higher rate of primisulfuron, regardless of the surfactant. Primisulfuron at 40 g ha⁻¹ controlled 43% of green foxtail without surfactant, which increased to 65% with the NIS and 83% with the OWA. Primisulfuron with a surfactant markedly reduced the fresh weight of green foxtail compared with primisulfuron applied alone, regardless of the primisulfuron rate and surfactant type. The scanning electron micrographs showed a uniform deposit of spray droplets, with close contact of the droplets to the leaf epicuticular surface in green foxtail in the presence of a surfactant compared with no surfactant. The enhanced primisulfuron activity on green foxtail with surfactants was related to the reduced contact angle and uniform deposition of the primisulfuron spray droplets on the leaf surface.     

Pharmacokinetic behaviour of fenbendazole in buffalo and cattle

Sanyal, P.K. Pharmacokinetic behaviour of fenbendazole in buffalo and cattle. J. vet. Pharmacol. Therap. 17, 1–4.
Concentrations of fenbendazole and of drug metabolites in plasma were measured in buffalo and cross-bred cattle after single intraruminal administration at two different doses. Plasma concentrations of the parent compound fenbendazole and the two metabolites, viz. oxfendazole and fenbendazole sulfone, were much lower in buffalo compared with cattle, at a dose of 7.5 mg/kg body weight as indicated by lower area under concentration curve and concentration maximum. At a dose of 15 mg/kg body weight there were corresponding increases in plasma metabolite concentrations in cattle. However, buffaloes did not show a similar corresponding increase.