Body fluid concentrations of ampicillin trihydrate in 6 horses after a single intramuscular dose.

This research discusses the examination of fluid concentrations of ampicillin trihydrate given as a single intramuscular dosage in six adult horses. The study focuses on analyzing level changes of the drug in various body fluids over a period of 48 hours.

Study Design and Methodology

• For this experiment, a single group of six adult mares were employed. Each received a single, intramuscular dose of ampicillin trihydrate. The dosage given was proportional to body weight, at 20 milligrams per kilogram.
• The experiment adopted a serial measurement method to monitor any changes in drug concentration in various body fluids over the designated timeframe of 48 hours. Four different types of fluids were inspected: serum, synovial fluid, peritoneal fluid, and urine.

Observations and Findings

• The mean peak serum ampicillin concentration in the tested horses was found to be 2.49 micrograms per milliliter, which occurred at the 6-hour mark.
• Ampicillin presence was also noted in synovial and peritoneal fluids. The drug reached its height in synovial fluid at 6 hours with an average concentration of 1.65 micrograms per milliliter and in peritoneal fluid at 4 hours with an average concentration of 1.81 micrograms per milliliter.
• The concentrations in both synovial and peritoneal fluids declined in parallel to the serum concentration and were still found at detectable levels at the end of the 48-hour period.
• A higher concentration of ampicillin was observed in the urine of the test subjects. The mean peak concentration was recorded as 1364.9 micrograms per milliliter at the 4-hour mark, making it significantly higher than the levels detected in other fluids.

Conclusions

• The study provides critical insights into the pharmacokinetics of ampicillin in horses, with a specific focus on how the drug’s concentration changes in different body fluids after intramuscular administration.
• The results show that the injected ampicillin is adequately circulated throughout the horse’s body, entering serum, synovial fluid, and peritoneal fluid, and being excreted via the urine. This can be useful information when considering the use and efficacy of ampicillin in veterinary medicine.