Pharmacokinetics of acyclovir after single intravenous and oral administration to adult horses.

This is a study about the performance and effects of the drug Acyclovir in horses, analyzing how it’s absorbed and processed in the body after being administered intravenously and orally.

Study Design

• The study included six healthy adult horses that were part of a randomized cross-over study, following a 3 x 3 Latin square design. This is a research design that aims to control the variation in an experiment that could be coming from two sources, making the results more reliable.
• Each horse received three different treatments: Acyclovir was provided intravenously and orally in two different doses.
• To ensure no carry-over effects of the treatments, a 2-week washout period was set between each administration.

Methods

• Blood samples were obtained from the horses for testing. The amount of acyclovir present in the samples was identified using a technique known as reversed-phase, high-performance liquid chromatography with fluorescence detection. The accuracy, precision, and recovery of the assay were determined to be satisfactory.
• The serum containing the drug was processed and then injected onto a C18 column, a component used to separate compounds present in the serum. Elution, or separation of elements, was carried out under isocratic conditions, meaning a constant composition of the solvent.

Results

• The study found that oral administration of the drug led to high variability in its levels over time, low maximum concentration (Cmax), and poor bioavailability (the proportion of the drug that enters the circulation when introduced into the body).
• The researchers observed that a higher dose of 20mg/kg was linked with an average maximum concentration of 0.19 microg/mL. However, the bioavailability was still low, at 2.8%.
• The results suggested that the concentrations of acyclovir required to inhibit equine herpesvirus are significantly higher than those achieved through the dosages used in this study.

Conclusion

• The findings of the research do not support the use of acyclovir through oral administration up to doses of 20mg/kg, as they did not appear to provide a therapeutic benefit.