Plasma disposition and fecal elimination of doramectin after oral or intramuscular administration in horses.

The research paper discusses a study where scientists analyzed how doramectin, a medication often used to treat parasites in animals, behaves in a horse’s body when given orally or through an injection.

Study Design and Participants

• Ten healthy horses were the subjects of this study and were divided into two equal groups.
• Each horse received a specific dose of doramectin, based on its body weight.
• Group 1 were given the drug orally, whereas Group 2 received it via intramuscular injection.

Data Collection

• Blood and fecal samples were collected over a 60-day period post-treatment.
• Dynamic changes in doramectin concentration were measured using high-performance liquid chromatography (HPLC).
• A non-compartmental kinetic analysis was done to understand the drug’s behavior in the horse’s body.

Findings

• The detection period of doramectin in the horse’s system differs depending on the mode of administration. After oral administration, it was detected for up to 30 days, while after intramuscular administration, it stayed up to 60 days.
• The peak plasma concentrations did not significantly differ between oral and intramuscular administration routes. However, the area under the concentration-time curve (AUC), which reflects the drug’s exposure, was significantly greater for the group that received doramectin via injection.
• The mean residence time (MRT), or the average time doramectin stayed in the body, was longer for the horses who received the drug through injection.
• The peak fecal concentration is significantly higher in horses treated orally than in those treated with an injection.

Conclusion

• The mode of doramectin administration impacts its plasma disposition kinetics, bioavailability, and fecal elimination. This result means that how the drug interacts with the horse’s body varies depending on whether the drug is given orally or injected directly into the muscle.