Pharmacokinetics of tiludronate in horses: A field population study.

The research focuses on analyzing the plasma concentrations of a drug called tiludronate, used to treat bone conditions in horses, under real-world conditions. The study aims to estimate the detection times for doping control in race and sport horses.

Study Objective and Methodology

• The primary goal of this study was to measure the levels of tiludronate, a bisphosphonate drug used for treating diverse bone conditions, under real-world conditions in a population of race and sport horses.
• The study used a pharmacokinetic population model to estimate the detection times of the drug for doping control purposes.
• The study was conducted on 39 race or sport horses diagnosed with bone conditions based on a lameness examination and then treated with tiludronate.
• The horses received an intravenous dosage of 1 mg/kg of tiludronate, and their blood samples were collected at various intervals after the drug administration. These intervals were 10, 20, 30, 40, and 50 days post the tiludronate administration.
• The researchers used High-Performance Liquid Chromatography/Electrospray Ionization Mass Spectrometry (HPLC/ESI-MS) for quantifying tiludronate.

Analysis and Results

• Using nonlinear mixed-effects modelling (population approach), the researchers analysed the tiludronate concentrations identified after drug administration.
• Monte Carlo simulations were then used to generate a prediction interval to estimate the concentration of horses predicted to depict levels below the potential screening limits.
• Significantly, the study detected pharmacokinetic differences between healthy experimental horses and the horses being treated under field conditions. Also, the level of training showed its effect on the plasma tiludronate.

Conclusions and Impact

• Though the study had limitations like a restricted number of horses in each group and the specific disease being treated with tiludronate is unknown, the research outcomes provide valuable insights for authorities in racing and other sports.
• Specifically, this research can help these authorities provide a detection time for the medication control of tiludronate reflecting field or real-world conditions.
• More broadly, this study design and data modelling serve as a guide on how to estimate detection times directly from the target horse population rather than relying solely on experimental horses.