Pharmacokinetics of oxfendazole in goats: a comparison with sheep

In goats, there was a linear correlation of area under the plasma concentration-time curve (AUC) with dose in the range 0-20 mg/kg as single dosages of oxfendazole (OFZ). The bioavailability of OFZ after oral administration was lower in goats than in sheep. The repetition of three administrations at 24 h intervals produced significant increase in the AUC in comparison with a single administration equivalent to the total dosage (1 X 5.0 and 3 X 1.7 mg/kg). Infection with O. circumcincta produced a 33% decrease in the bioavailability of OFZ.

Pharmacokinetics of albendazole administered by an intraruminal pulse release electronic device in cattle

Albendazole was administered to 12 young Charolais cattle, 300 kg bodyweight, using an intraruminal pulse release electronic device. The device released 2 g albendazole three times at 31 day intervals. The kinetic study of two main metabolites of albendazole in all animals at the time of each release showed that on 36 occasions the devices worked at the expected time; the mean kinetic profiles were nearly identical at first, second and third release. A good repeatability was generally also noticed for each animal individually; the bioavailability of the drug did not seem to be different from that obtained after administration of albendazole as an oral drench.

[Bemetil pharmacokinetics in an experiment on rats]

Pharmacokinetics of bemetil (2-ethyl-mercaptobenzimidazole), a representative of the group of actoprotectors, was studied at intravenous and intragastric administration during the experiment on rats by using gas-liquid chromatography. It was found that at intragastric administration the drug rapidly appeared in the systemic circulation, reached the maximal concentration in one hour; the character of bemetil elimination from the blood was biexponential at both routes of administration. The two-compartment model was used for calculation of the main pharmacokinetic constants and bioavailability. The analysis of the experimental findings on urinary excretion of bemetil made it possible to conclude that little amount of the drug (0.56%) is excreted in the urine in the unchanged form; most amount of bemetil is excreted in the form of metabolites and in the bound state.