Pharmacokinetic/pharmacodynamic approach to assess irrelevant plasma or urine drug concentrations in postcompetition samples for drug control in the horse.

The current performance of analytical techniques used for drug control in horses lead the Regulatory Authorities to decide whether trace levels of drugs legitimately used for therapeutic medication should or should not be reported. Here, we propose a well-ordered and nonexperimental pharmacokinetic/pharmacodynamic approach for the determination of irrelevant drug plasma (IPC) and urine concentrations (IUC). The published plasma clearance is used to transform an effective (marketed) dose into an effective concentration (EPC).

Cortisol concentrations in post competition horse urine: a French and British survey.

The purpose of the present report was to estimate the population parameters of cortisol concentrations in urine, an endogenous hormone used as a 'doping' agent and for which an international threshold (1.0 micrograms/ml) has been proposed. Two data bases (French and UK) corresponding to 112 and 142 samples, respectively were considered.

Cortisol disposition and production rate in horses during rest and exercise.

The influence of a 56-km endurance exercise on cortisol kinetics and production rate was evaluated in six horses administered [3H]cortisol. Exercise resulted in an immediate two- to threefold increase in plasma cortisol, with values returning very rapidly to preexercise levels. During exercise, clearance and steady-state volume of distribution of total cortisol were greatly increased (338 +/- 95 vs.

Non-invasive and quantitative evaluation of post-injection muscle damage by pharmacokinetic analysis of creatine kinase release.

Intramuscular administration of veterinary drugs can induce severe muscle damage resulting in economic losses and residue persistence. Local tolerance is usually evaluated by macroscopic examination of the injection site requiring euthanasia of a large number of animals. A non-invasive quantitative method, based on the pharmacokinetic analysis of creatine kinase (CK) release from muscle, is proposed for the evaluation of post-injection muscle damage.

A non-invasive and quantitative method for the study of tissue injury caused by intramuscular injection of drugs in horses.

The present study was undertaken to measure the weight of muscle destroyed by an intramuscular injection of phenylbutazone (PBZ) in horses. In six horses, CK disposition parameters were evaluated after intravenous (i.v.