Enrofloxacin and marbofloxacin in horses: comparison of pharmacokinetic parameters, use of urinary and metabolite data to estimate first-pass effect and absorbed fraction.
Abstract: Enrofloxacin and marbofloxacin are two veterinary fluoroquinolones used to treat severe bacterial infections in horses. A repeated measures study has been designed to compare their pharmacokinetic parameters, to investigate their bioavailability and to estimate their absorbed fraction and first-pass effect by using plasma, urinary and metabolite data collected from five healthy mares. Clearance and V(d(ss)) were greater for enrofloxacin (mean +/- SD = 6.34 +/- 1.5 mL/min/kg and 2.32 +/- 0.32 L/kg, respectively) than for marbofloxacin (4.62 +/- 0.67 mL/min/kg and 1.6 +/- 0.25 L/kg, respectively). Variance of the AUC(0-inf) of marbofloxacin was lower than that for enrofloxacin, with, respectively, a CV = 15% and 26% intravenously and a CV = 31% and 55% after oral administration. Mean oral bioavailability was not significantly different between marbofloxacin (59%) and enrofloxacin (55%). The mean percentage of the dose eliminated unchanged in urine was significantly higher for marbofloxacin (39.7%) than that for enrofloxacin (3.4%). Absorbed fraction and first-pass effect were only determinable for enrofloxacin, whereas the percentage of the dose absorbed in the portal circulation was estimated to be 78% and the fraction not extracted during the first pass through the liver was 65%. Consequently, the moderate observed bioavailability of enrofloxacin appears to be mainly caused by hepatic first-pass effect.
Publication Date: 2006-09-09 PubMed ID: 16958777DOI: 10.1111/j.1365-2885.2006.00752.xGoogle Scholar: Lookup
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- Comparative Study
- Journal Article
- Research Support
- Non-U.S. Gov't
Summary
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This research study compares how horses’ bodies absorb and process two antibiotics, enrofloxacin and marbofloxacin. The study discovered differences in how each drug was absorbed and metabolized, with enrofloxacin notably being more significantly affected by initial liver processing.
Research design and methods
- Researchers conducted a repeated measures study using plasma, urine, and metabolic data from five healthy horses.
- Pharmacokinetic parameters of both antibiotics, enrofloxacin and marbofloxacin, were compared.
- The researchers sought to understand how each drug gets absorbed and excreted by estimating the absorbed fraction and first-pass effect.
Key findings
- Enrofloxacin had a higher clearance rate and volume of distribution compared to marbofloxacin, indicating the former gets metabolized and distributed throughout the body faster.
- There was less variability in the area under the concentration-time curve (AUC) for marbofloxacin than enrofloxacin, suggesting a more consistent absorption pattern with marbofloxacin.
- The oral bioavailability-mean percentage of the drug that reaches systemic circulation after oral administration-of both drugs wasn’t significantly different. However, marbofloxacin was found in urine more often, meaning less of the drug is metabolized and altered by the body before excretion.
- For enrofloxacin, researchers were able to determine its absorbed fraction and first-pass effect (how much of the drug is metabolized during its first passage through the liver before reaching systemic circulation). The fraction not extracted during the first pass was higher indicating a stronger first-pass effect and accordingly a moderate bioavailability.
Conclusion
- The observed difference in bioavailability between marbofloxacin and enrofloxacin could be mainly due to the hepatic first-pass effect, which affects the amount of medication initially available for therapeutic activity.
- The findings can guide veterinary practitioners in their choice of fluoroquinolone-based antibiotic for treating bacterial infections in horses.
Cite This Article
APA
Peyrou M, Bousquet-Melou A, Laroute V, Vrins A, Doucet MY.
(2006).
Enrofloxacin and marbofloxacin in horses: comparison of pharmacokinetic parameters, use of urinary and metabolite data to estimate first-pass effect and absorbed fraction.
J Vet Pharmacol Ther, 29(5), 337-344.
https://doi.org/10.1111/j.1365-2885.2006.00752.x Publication
Researcher Affiliations
- Biomedical Sciences, Atlantic Veterinary College, University of Prince Edward Island, Charlottetown, PE, Canada.
MeSH Terms
- Administration, Oral
- Animals
- Anti-Infective Agents / administration & dosage
- Anti-Infective Agents / metabolism
- Anti-Infective Agents / pharmacokinetics
- Area Under Curve
- Biological Availability
- Ciprofloxacin / metabolism
- Ciprofloxacin / pharmacokinetics
- Enrofloxacin
- Enzyme Inhibitors / administration & dosage
- Enzyme Inhibitors / metabolism
- Enzyme Inhibitors / pharmacokinetics
- Female
- Fluoroquinolones / administration & dosage
- Fluoroquinolones / metabolism
- Fluoroquinolones / pharmacokinetics
- Half-Life
- Horses
- Injections, Intravenous
- Quinolones / administration & dosage
- Quinolones / metabolism
- Quinolones / pharmacokinetics
Citations
This article has been cited 2 times.- Sun H, Pang KS. Physiological modeling to understand the impact of enzymes and transporters on drug and metabolite data and bioavailability estimates. Pharm Res 2010 Jul;27(7):1237-54.
- Yang B, Liu S, Cheng J, Qu H, Guo Y, Ji C, Wang Y, Zhao S, Huang S, Zhao L, Ma Q. Pharmacokinetics of Enrofloxacin in Plasma, Urine, and Feces of Donkey (Equus asinus) after a Single Intragastric Administration. Antibiotics (Basel) 2024 Apr 12;13(4).
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