Effect of repeated biopsy sampling on endometrial concentrations of sodium benzylpenicillin following intramuscular injection in pony mares.

The study investigates how repeated biopsy sampling affects the concentration of sodium benzylpenicillin in the endometrium of anestrous pony mares after being administered through an intramuscular injection.

Overview of the Research

• The research revolves around exploring the effect of repeated biopsy sampling on the concentration of sodium benzylpenicillin in the endometrium. This is achieved by examining biopsy samples obtained from anestrous pony mares who received intramuscular injections of the antibiotic at a dose of 22,000 iu per kilogram of body weight.
• Along with tissue samples, blood serum samples were also collected at the same time intervals and analyzed for penicillin content, allowing a comparative study of concentrations in both blood and tissue.

Experiment 1

• In the first experiment, each mare had one pair of blood and tissue samples taken at different time points, ranging from five to 360 minutes after the injection of penicillin. This measure was designed to track the concentration of the drug over time in both the serum and the endometrial tissue.

Experiment 2

• The second experiment involved more frequent sampling, with each mare subjected to six consecutive samples taken at intervals from five to 300 minutes after the injection. This approach helped assess the possible impact of repeated biopsy sampling on endometrial concentration of penicillin.

Results and Conclusion

• It was found that the peak concentration for both serum and endometrial tissue occurred between 15 and 30 minutes after the injection. However, the concentration of penicillin in endometrial tissue was generally lower than that in the serum, with one exception in experiment 2 where, after 180 minutes, the tissue concentration exceeded the serum concentration.
• The observation of greater penicillin concentration in endometrial tissue after repeated biopsy sampling over the specified time intervals suggests that continuous sampling might cause an increase in the endometrial content of the drug, likely due to inflammation or increased blood flow to the area.