Diffusion of enrofloxacin to pregnancy fluids and effects on fetal cartilage after intravenous administration to late pregnant mares.

The research is about testing the effects of an antibacterial drug, enrofloxacin, on pregnant horses at late stages of gestation and its diffusion into the fetus via the placenta. It aims to explore if this drug is a viable treatment option for infections and checking the impacts on fetal cartilage, to ensure the well-being of the unborn foal.

Objective and Methodology

• The research aims to determine if enrofloxacin gets to the fetus when given to pregnant mares and the impact it has on the fetal cartilage.
• Three sets of healthy mares were selected, each at 260 days of gestation. One group was given no treatment, another group received therapeutic doses of the drug, and the last group was given double the therapy dose.
• The fetal fluids were collected at different stages, and after the 11th day, premature delivery was induced. Fluids and plasma samples were then collected and analyzed.
• The concentrations of enrofloxacin and its metabolite, ciprofloxacin, in plasma and fetal fluid were measured using liquid chromatography-mass spectrometry.
• The fetal articular cartilage was examined for possible lesions both macroscopically and histologically.

Results

• The research results indicated that enrofloxacin and ciprofloxacin reached the minimum inhibitory concentrations for common pathogens in all fluids.
• Even though ciprofloxacin level did not increase in maternal plasma with the increased dose of enrofloxacin, allantoic fluid showed a 10-fold increase relative to fetal trough plasma concentrations.
• The use of enrofloxacin at recommended doses did not result in cartilaginous lesions in fetuses.

Conclusion

• The research team concluded that the short-term administration of enrofloxacin to pregnant mares resulted in detectable levels of the drug and its metabolite in fetal fluids.
• It was also noted that this did not result in macroscopic or microscopic lesions in the fetus.
• The study cautions, however, that its findings are limited to just one point of gestation and that the mares were healthy at the time of treatment. Further research is therefore needed to fully understand the impact of enrofloxacin at different stages of pregnancy, after longer treatment durations, and once the foals are weight-bearing.
• Notwithstanding, the study hints that enrofloxacin could be viable for treating select bacterial infections in pregnant mares, provided additional research validates the initial findings.