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Research in veterinary science1995; 58(3); 227-231; doi: 10.1016/0034-5288(95)90107-8

Stability of penicillin G, ampicillin, amikacin and oxytetracycline and their interactions with food in in vitro simulated equine gastrointestinal contents.

Abstract: Penicillin G was extensively (84.7 per cent) and amikacin moderately (14.4 per cent) degraded when incubated for one hour in a chloride buffer at pH 1.9 designed to mimic the equine gastric pH. Ampicillin and oxytetracycline were stable at pH 1.9. Penicillin and ampicillin were moderately stable (more than 90 per cent) when incubated in equine caecal liquor for three hours but were degraded by about 65 per cent after 24 hours. More than 80 per cent of the initial concentrations of amikacin and oxytetracycline were recovered after 24 hours' incubation in equine caecal liquor. The concentrations of short chain fatty acids in equine caecal liquor were not affected by incubation with penicillin G, ampicillin, amikacin or oxytetracycline. More than 84 per cent of penicillin G and amikacin became bound to hay in buffers at pH 1.9 and pH 7.0. Ampicillin did not become bound to hay at pH 1.9, but more than 60 per cent became bound at pH 7.0.
Publication Date: 1995-05-01 PubMed ID: 7659846DOI: 10.1016/0034-5288(95)90107-8Google Scholar: Lookup
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  • Journal Article
  • Research Support
  • Non-U.S. Gov't

Summary

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The research article discusses the stability and degradation rates of various antibiotics, specifically penicillin G, ampicillin, amikacin, and oxytetracycline, along with their interaction with food in a simulated equine gastrointestinal environment.

Antibiotic Stability in Gastric pH

  • The scientists simulated the acidic environment of the equine stomach using a chloride buffer at pH 1.9. Within this environment, they observed different levels of degradation for the four tested antibiotics.
  • Penicillin G and amikacin showed substantial degradation after one hour of incubation – 84.7% for penicillin G and 14.4% for amikacin.
  • On the other hand, ampicillin and oxytetracycline demonstrated significant stability under the same conditions, showing no signs of degradation.

Antibiotic Stability in Equine Caecal Liquor

  • The study also looked at the stability of the antibiotics within equine caecal liquor, a fluid found in the horse’s cecum, over a span of 24 hours.
  • Initially, penicillin and ampicillin appeared to be stable, retaining more than 90% of their original concentration after three hours.
  • However, after 24 hours, a degradation of about 65% was noted for both antibiotics.
  • Oxytetracycline and amikacin showed better stability, with more than 80% of their initial concentrations remaining after 24 hours of incubation.
  • Additionally, the research found that the presence of these antibiotics did not affect the concentration of short-chain fatty acids in the equine caecal liquor.

Antibiotic Interaction with Hay

  • The researchers investigated how the antibiotics interact with food, specifically hay, as part of a horse’s diet. They studied this by incubating the antibiotics with hay in buffers at pH 1.9 and pH 7.0.
  • Results showed that large amounts of penicillin G and amikacin became bound to hay in both acidic (pH 1.9) and neutral (pH 7.0) conditions – over 84% in each case.
  • A significant difference was seen with ampicillin, which did not bind to hay in an acidic environment but showed more than a 60% binding rate in a neutral pH environment.

The findings of this study provide crucial insights into how these antibiotics perform within the digestive environment of horses, including their interaction with food. The observed degradation rates and binding behaviors can influence decisions on the optimal timing and conditions for antibiotic administration.

Cite This Article

APA
McKellar QA, Horspool LJ. (1995). Stability of penicillin G, ampicillin, amikacin and oxytetracycline and their interactions with food in in vitro simulated equine gastrointestinal contents. Res Vet Sci, 58(3), 227-231. https://doi.org/10.1016/0034-5288(95)90107-8

Publication

ISSN: 0034-5288
NlmUniqueID: 0401300
Country: England
Language: English
Volume: 58
Issue: 3
Pages: 227-231

Researcher Affiliations

McKellar, Q A
  • Department of Veterinary Pharmacology, University of Glasgow Veterinary School.
Horspool, L J

    MeSH Terms

    • Amikacin / metabolism
    • Ampicillin / metabolism
    • Animals
    • Anti-Bacterial Agents / metabolism
    • Cecum / metabolism
    • Food-Drug Interactions
    • Gastrointestinal Contents
    • Horses / metabolism
    • Hydrogen-Ion Concentration
    • In Vitro Techniques
    • Oxytetracycline / metabolism
    • Penicillin G / metabolism
    • Time Factors

    Grant Funding

    • Wellcome Trust

    Citations

    This article has been cited 1 times.
    1. Song Y, Day CM, Afinjuomo F, Tan JE, Page SW, Garg S. Advanced Strategies of Drug Delivery via Oral, Topical, and Parenteral Administration Routes: Where Do Equine Medications Stand?. Pharmaceutics 2023 Jan 4;15(1).
      doi: 10.3390/pharmaceutics15010186pubmed: 36678815google scholar: lookup