Clinical Feasibility and Airway Deposition of Nebulized Voriconazole in Healthy Horses.

The study focused on the potential use of voriconazole, a drug used against fungal infections, as a treatment for lung infections in horses. The researchers particularly wanted to determine if administering this drug through nebulization would result in a higher concentration in the pulmonary epithelial lining fluid than the plasma. The conclusion was that the drug did not reach sufficient concentrations in the targeted areas; hence, its use in this manner is not recommended.

Objective of the Study

• The primary objective of this research was to determine whether delivering voriconazole via a Flexineb nebulizer would result in desirable concentration of the drug in horses’ lower airways. Apart from this, investigating the concentration of the voriconazole in horses’ upper airways was a secondary aim.

Research Hypothesis

• The researchers hypothesized that the concentration of voriconazole achieved in the pulmonary epithelial lining fluid would be greater than its plasma concentration when delivered via nebulization.

Research Methodology

• A solution of voriconazole [Vfend-6.25 mg/mL], in amounts of 100 (for 2 horses), 200 (for 3 horses), and 500 mg (for 1 horse), was nebulized for 6 healthy geldings. Observations included clinical responses, nebulization duration, and voriconazole concentration at various time points in plasma, bronchoalveolar lavage fluid, and nasopharyngeal wash samples.
• A second part of the study involved nebulizing an additional five healthy geldings with 200 mg of Vfend. Again, the concentration of voriconazole in nasopharyngeal wash samples was measured before and after nebulization over a span of 8 hours. The antifungal activity of the bronchoalveolar lavage fluid and nasopharyngeal wash samples was determined using agar disk diffusion.

Research Findings

• The concentrations of voriconazole were generally below detection levels in plasma, bronchoalveolar lavage fluid supernatants, and cell pellets across all time points regardless of the dose used, except in the case of the bronchoalveolar lavage fluid cell pellet where 500 mg of Vfend had been nebulized.
• In the second part of the study, nasopharyngeal wash samples showed gradually decreasing concentrations of the drug, and only samples procured immediately after nebulization displayed antifungal activities.

Conclusion

• Based on the collected data, the researchers ultimately concluded that the use of a nebulized Vfend solution is not recommended for the treatment of pneumomycosis in horses due to the inadequacy of drug concentrations in the targeted areas.