Serum concentrations and pharmacokinetics of enrofloxacin after intravenous and intragastric administration to mares.

The research article discusses the study of serum levels and pharmacokinetics of enrofloxacin in horses, administered either through intravenous injection or intragastric intake. Three experiments were carried out, analyzing its effects and application in treating bacterial infections in horses.

Experiment 1: Intravenous Administration

• The first experiment involved administering an injectable formulation of enrofloxacin to horses through intravenous injection (IV).
• A single dose of 7.5 mg/kg of body weight was used.
• The mean serum concentration of the drug after 5 minutes of administration was 9.04 microg/mL, which reduced to 0.09 microg/mL after 24 hours.
• Pharmacokinetic data, such as the elimination half-life (5.33 +/- 1.05 h) and the area under the serum concentration vs time curve (AUC of 21.03 +/- 5.19 mg x h/L), were listed.

Experiment 2: Intragastric Administration with Injectable Solution

• In the second experiment, the injectable formulation of enrofloxacin was administered orally (intragastric or IG).
• The peak serum concentration after 4 hours of intake was 0.94 +/- 0.97 microg/mL, declining to 0.29 +/- 0.12 microg/mL after 24 hours.
• Owing to the highly variable absorption rate of enrofloxacin after intragastric administration, individual pharmacokinetic values for each mare couldn’t be precisely determined.

Experiment 3: Intragastric Administration with Poultry Formulation

• The third experiment involved the intragastric administration of a different formulation of enrofloxacin, typically used for poultry.
• The peak serum concentration after 45 minutes of intake was 1.85 +/- 1.47 microg/mL, dropping to 0.19 +/- 0.06 microg/mL after 24 hours.
• The drug’s elimination half-life was 10.62 +/- 5.33 h and its AUC was 16.30 +/- 4.69 mg x h/L.
• The bioavailability of this formulation (the degree and rate at which the drug is absorbed) was calculated to be 78.29 +/- 16.55%.

Effectiveness Against Bacterial Cultures

• Minimum inhibitory concentrations of enrofloxacin were measured against bacterial cultures from horses obtained over an 11-month period.
• The minimum quantity of enrofloxacin required to inhibit 90% of bacterial isolates was 0.25 microg/mL for Staphylococcus aureus, Escherichia coli, Salmonella spp., Klebsiella spp., and Pasteurella spp.
• The poultry formulation was deemed well-tolerated and potentially useful in treating bacterial infections in adult horses.
• The research concluded with a recommendation against the oral use of the injectable enrofloxacin solution.