In vitro efficacy of lufenuron against filamentous fungi and blood concentrations after PO administration in horses.

The research investigates the potential of lufenuron, primarily an insecticide, as a treatment for fungal infections in horses. The experiment evaluates its effectiveness against certain fungi as well as its concentration in horse blood after oral administration.

Research Purpose and Methodology

• The study aimed to understand two main aspects: the in vitro efficiency of lufenuron against certain fungi (specifically Aspergillus and Fusarium), and the ability of this substance to reach an effective concentration in the horse’s bloodstream after oral administration.
• To test the in vitro effectiveness, lufenuron solutions with concentrations up to 700 microg/mL were used against fungal colonies isolated from diseased horse corneas.
• To examine the potential of lufenuron to reach the necessary blood concentration, 21 adult horses were orally given lufenuron following three different treatment regimens. Each regimen had a specified dosage per kg body weight and frequency. Blood samples were taken after drug administration and up to 96 hours afterward, and were analyzed using high-performance liquid chromatography.

Statistical Analysis and Results

• Statistical analyses were carried out using analysis of variance and Fischer’s Least Significant Difference test, with the significance level set at P < .05.
• The results showed that lufenuron had no effect on the in vitro growth of either Aspergillus or Fusarium.
• Lufenuron was detected in the blood of almost all horses, suggesting the substance is absorbed into the bloodstream. There were no observed adverse effects in the horses.
• The maximum concentration of lufenuron in horse blood was considerably lower than the ineffective concentrations found during the in vitro tests.

Conclusions and Further Directions

• The study concludes that despite being absorbed into the bloodstream, the concentration of lufenuron achieved is lower than the ineffective level determined in the in vitro tests.
• The researchers suggest that any further use of lufenuron as an antifungal agent in horses should be based on proven effectiveness against clinically relevant fungi strains, supported by pharmacokinetic data confirming sufficient lufenuron concentrations in target tissues.
• This research points towards the need for further investigation and trials to confidently determine lufenuron’s potential as an antifungal treatment in horses.