Oxytetracycline hydrochloride in the horse: serum, synovial, peritoneal and urine concentrations after single dose intravenous administration.

The research article presents a study on how a single dose of intravenously injected oxytetracycline HCl (a type of antibiotic) impacts serum, synovial fluid, peritoneal fluid, and urine concentrations in adult mares over a 48-hour period.

Research Methodology

• Six adult mares were selected for this study.
• Each mare was given a single intravenous injection of oxytetracycline HCl. The dosage was 5 mg/kg, and the concentration of the administered drug was 50 mg/ml.
• The researchers collected and analyzed samples of serum, synovial fluid, peritoneal fluid, and urine from the mares over the course of 48 hours following the oxytetracycline injection.

Key Findings

• The highest measured concentration of oxytetracycline in serum was found to be 8.01 mcg/ml 30 minutes after drug administration.
• The drug was detected in both synovial fluid and peritoneal fluid, with the average peak concentraions being 4.43 mcg/ml and 4.20 mcg/ml respectively. The peak concentrations in synovial fluid were found 30 minutes after drug administration, whereas peak concentrations in peritoneal fluid were observed one hour after drug administration.
• The concentrations of oxytetracycline in serum, synovial fluid, and peritoneal fluid steadily declined in tandem over the 48-hour observation period, and the drug was not detectable in these fluids after this time period.
• The concentration of oxytetracycline in urine was found to be significantly higher than in the other fluids, reaching a peak concentration of 1565.2 mcg/ml 30 minutes after drug administration.

Conclusion

• This study provides insights into how oxytetracycline HCl is distributed within different body fluids following intravenous administration. This could have implications for effective dosing and treatment protocols when using this antibiotic in equine veterinary medicine.