Pulmonary pharmacokinetics of desfuroylceftiofur acetamide after nebulisation or intramuscular administration of ceftiofur sodium to weanling foals.

The research aimed to investigate the effectiveness and safety of nebulised ceftiofur sodium – an antibiotic, in treating horse bronchopneumonia. The study found that the nebulised drug is well-tolerated, induces no airway inflammation, and keeps drug concentrations above minimum levels necessary to inhibit bacterial growth in horse lungs for approximately 24 hours.

Objective and Methodology

• The main objective of this study was to evaluate the concentration of desfuroylceftiofur acetamide (DCA), a metabolite of ceftiofur sodium, in the plasma and pulmonary epithelial lining fluid (PELF) of young horses (foals) after administering the drug either as an aerosol (nebulisation) or via intramuscular injection. The researchers also aimed to check if nebulisation of ceftiofur sodium causes inflammation in the airways.
• The experimental study involved randomly dividing weanling foals into two groups. One group was given ceftiofur sodium (2.2 mg/kg of body weight daily for five doses) through intramuscular injection, while the other group received the same dose through nebulisation.
• After the 1st and 5th doses, the investigators measured the DCA concentrations in both the plasma and PELF. Additionally, they obtained bronchoalveolar lavage samples from the foals after the 5th dose to perform differential cell counts and assess signs of inflammation.

Results

• Results indicated significantly lower peak concentrations and area under the curve of DCA in the plasma of foals taking the drug through nebulisation compared to those taking it through intramuscular routes.
• Conversely, the concentration of DCA in the PELF of foals using the nebulised drug was significantly higher than the intramuscularly injected counterparts, indicating the drug’s desired presence in the lungs for this respiratory condition.
• Furthermore, there was no significant difference in cell concentration and differential cell count in the bronchoalveolar lavage fluid of foals nebulised with ceftiofur sodium compared to those treated with saline, suggesting that nebulised administration does not induce airway inflammation.

Conclusion

• The study concludes that nebulisation of the ceftiofur sodium is not just well-tolerated but also keeps DCA concentrations in PELF above the minimum inhibitory concentration needed to control Streptococcus zooepidemicus growth (the bacterial strain commonly causing respiratory infections in horses) for approximately 24 hours. This shows the potential of nebulised ceftiofur sodium as a treatment for bacterial infections affecting the lower respiratory tract of horses. However, the researchers recommend further investigation for a more conclusive assessment.