Use of cholinesterase activity in monitoring chlorpyrifos exposure of steer cattle after topical administration.

The aim of this work was to study the pharmacokinetic behavior and the inhibitory effect of acetylcholinesterase (AChE) and butyrylcholinesterase (BChE) activities of chlorpyrifos (CPF) in steer cattle after pour-on administration. Determination of cholinesterase activity in plasma and erythrocyte was carried out according to Ellman kinetic method. CPF was analyzed by gas chromatography.

Effects of age on the pharmacokinetics of single dose sulfamethazine after intravenous administration in cattle.

Sulphonamides are still being used widely, influenced by the low cost and the efficacy against many common bacterial infections, since they present a broad spectrum of activity. The aim of this study was to determine the effect of age on the pharmacokinetic/pharmacodynamics (PK/PD) integration of intravenous sulfamethazine (60 mg/kgbw) in cattle, and the possible therapeutic outcomes. Six healthy female calves, at the age of one, three, seven and fifteen weeks were used.

Pharmacokinetics and pharmacodynamics of chlorpyrifos in male and female cattle after topical administration.

The aim of this work was to study the pharmacokinetic behaviour and the inhibitory effect on acetylcholinesterase and butyrylcholinesterase activities of chlorpyrifos in male and female cattle after pour-on administration. Determination of cholinesterase activity in plasma and erythrocyte was carried out according to Ellman kinetic method. The mean baseline activities were 9338.

Chronopharmacokinetic study of gentamicin in dogs.

The purpose of this experiment was to determine whether the time of day of single intravenous doses of gentamicin affects the drug's pharmacokinetics in dogs maintained under a 12 h light (08:00 to 20:00 h), 12 h dark (20:00 to 08:00 h) cycle. Using a crossover design, 6 mixed-breed male dogs received a single dose of 2 mg/kg of gentamicin at 8:00 or 20:00 h. Serial blood samples were collected and pharmacokinetic parameters were calculated following each timed dose.