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The intravenous, intramuscular and oral pharmacokinetics of ibuprofen in broiler chickens were investigated. In a preliminary study, plasma ibuprofen concentration-time profiles, following i.v. (25 mg/kg) dosing were best described by a 2-compartment model. After intravenous administration, the volume of distribution at steady-state (Vd(ss)), the total systemic clearance (ClB), the elimination half-life (t1/2 beta) and the MRT were 0.303 L/kg, 482.3 ml/h.kg, 2.71 h and 1.02 h, respectively. After intramuscular administration of ibuprofen, the tmax and Cmax were 0.37 h, and 42.2 micrograms/mL, respectively, with an estimated bioavailability of 46.7%. After oral administration of ibuprofen, the tmax and Cmax were 0.31 h and 23.91 micrograms/mL, respectively, with an estimated bioavailability of 24.2%. This is a preliminary study, examining the use of ibuprofen in broiler chickens, and should be followed by tissue residue and efficacy studies in different disease states.

Na+,K(+)-ATPase, Mg(2+)-activated ATPase, and Na(+)-ATPase activities of brain, heart, kidney, and small and large intestinal mucosa of broiler chickens exposed to heat stress (41 degrees C, 65% relative humidity for 6 h) and thermoneutral (25 degrees C, 65% relative humidity) conditions were determined. Brain and kidneys were found to have significantly higher Na+,K(+)-ATPase activities than those of heart and intestinal mucosa. Mg(2+)-activated ATPase and Na(+)-ATPase activities in the intestinal mucosa were higher than those of brain, kidneys, and heart under thermoneutral conditions. While there was a significant inhibition of total ATPase, Na+,K(+)-ATPase, Mg(2+)-activated ATPase, and Na(+)-ATPase activity of small and large intestinal mucosa of broiler chickens exposed to heat stress, the inhibitory effect was limited to total ATPase and Na+,K(+)-ATPase enzymes in kidneys. Heat stress produced a significant increase only in Mg(2+)-activated ATPase activity of the heart, without a remarkable change in all forms of ATPase activity in the brain. Heat stress significantly decreased the ratio of Na+,K(+)-ATPase to Mg(2+)-ATPase in the heart, kidneys, and small and large intestinal mucosa. The percentage of Na(+)-ATPase in Na+,K(+)-ATPase of brain, heart, and kidneys did not significantly change during heat stress, but the ratio in small and large intestinal mucosa increased significantly during heat stress. The severe disturbances in both serum electrolytes and acid-base balance observed in previous heat stress studies could partly be mediated by direct or indirect effects of heat stress on Na+,K(+)-ATPase, Mg(2+)-activated ATPase, and Na(+)-ATPase activities of kidneys, and small and large intestinal mucosa of broiler chickens.

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SummaryThe pharmacokinetics and plasma protein binding of BRB-I-28, a novel antiarrhythmic agent, were investigated in dogs. The plasma concentration-time profile of BRB-I-28, following an intravenous bolus dose of 10 mgJkg, can be adequately described by a 2-compartment open model. The mean volume of distribution at steady-state (Vdss) was 8.759 L/kg, the mean total systemic clearance (CL) was 1.289 ml/h/kg, and the mean elimination half-life (t' 12/1) was 4.645 hours. Following intravenous administration, approximately 1.85% of the dose was excreted in the urine (0 to 48 hours) as parent drug. Changes in plasma concentrations, after oral administration of BRB-I-28 20 mgJkg, were best described by a l-compartment open model. BRB-I-28 was rapidly absorbed (tmax = 1.22 hours and Cmax = 1.59 mgJL) with a rapid elimination rate (t'12kel = 1.583