Pharmacokinetics of voriconazole after oral and intravenous administration to horses.

The research describes the pharmacokinetics or drug absorption, distribution, and processing behavior of an antifungal medication called voriconazole in horses when administered orally and intravenously. It offers insights into the efficiency of the drug’s absorption, possible side effects, and its potential utility for treating horses with fungal infections.

Methodology

• The study was conducted on six adult horses, which were given voriconazole either intravenously (1 mg/kg) or orally (4 mg/kg).
• The plasma concentrations of voriconazole post-administration were assessed using high-performance liquid chromatography, a technique used commonly in biochemistry and analytical chemistry for identifying and quantifying components in a sample.

Physicochemical Analysis

• The researchers also determined the drug’s in vitro plasma protein binding and the octanol:water partition coefficient.
• These two factors play a significant role in a drug’s absorption, distribution, metabolism, and excretion.
• Plasma protein binding affects the drug’s distribution within the body and its elimination rate, and the octanol:water partition coefficient reflects the drug’s lipophilicity, influencing its absorption and penetration through cell membranes.

Results and Conclusions

• Voriconazole revealed a high bioavailability of 135.75% +/- 18.41% when given orally to horses, meaning that the drug was absorbed well by the body. This is indicated by the absorption rate exceeding 100%, implying more absorption than a standard intravenous dose.
• The drug’s elimination half-life, i.e., the time taken for half the drugs to be eliminated from the body, was found to be 13.11 hours +/- 2.85 hours.
• The maximum concentration of the drug in the plasma was found to be 2.43 micrograms/mL +/- 0.4 micrograms/mL.
• No adverse reactions were observed during the study, indicating the drug’s safety.
• The researcher concluded that a daily oral dose of voriconazole (4 mg/kg) could treat horses with fungal infections effectively.

Future Work

• Given the hyperlinear absorption of the drug and the potential for accumulation in the body, the study recommends further investigation to establish the appropriate dosing regimen for voriconazole in horses.