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Veterinary research communications1992; 16(2); 131-138; doi: 10.1007/BF01839010

The pharmacokinetics of a slow-release theophylline preparation in horses after intravenous and oral administration.

Abstract: The pharmacokinetics of a slow-release theophylline formulation was investigated following intravenous and oral administration at 10 mg/kg in horses. A tricompartmental model was selected to describe the intravenous plasma profile. The elimination half-life (t1/2 beta) was 16.91 +/- 0.93 h, the apparent volume of distribution (Vd) was 1.35 +/- 0.18 L/kg and the body clearance (ClB) was 0.061 +/- 0.009 L kg-1 h. After oral administration the half-life of absorption was 1.24 +/- 0.30 h, and the calculated bioavailability was above 100%. The t1/2 beta after oral administration was 18.51 +/- 1.75 h, only a little longer than that after intravenous administration. The slow release formulation did not exhibit any advantage in prolonging the t1/2 beta of theophylline in the horse.
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Publication Date: 1992-01-01 PubMed ID: 1496815DOI: 10.1007/BF01839010Google Scholar: Lookup
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Summary

This research summary has been generated with artificial intelligence and may contain errors and omissions. Refer to the original study to confirm details provided. Submit correction.

This research paper involves a study investigating pharmacokinetics – how drugs move within the body – of a slow-release form of the drug theophylline, in horses. The researchers found that the said formulation didn’t offer any benefits in extending the half-life of the drug.

Pharmacokinetics of Slow-Release Theophylline in Horses

The researchers focused on studying the ‘pharmacokinetics’ or the movement and interaction of a slow-release version of the drug theophylline in the bodies of horses. Theophylline is a drug primarily used to open up the bronchial tubes (air passages) in the lungs. Two modes of administration were considered – one, directly into the bloodstream or ‘intravenously’, and two, orally or through the mouth.

  • The drug was administered at a dosage strength of 10 milligrams per kilogram of the horse’s body weight.
  • The researchers used a ‘tricompartmental’ model to describe the intravenous plasma profile. This is a statistical model used to calculate how the drug disintegrates and spreads in the body over time.

Analyzing the Intravenous Administration

  • The ‘elimination half-life’ also known as t1/2 beta was calculated to be approximately 16.91 hours – meaning, it takes that much time for the concentration of the drug in the horse’s body to reduce by half.
  • They calculated the ‘volume of distribution’ (Vd) to be approximately 1.35 Liters per kilogram. This value indicates the extent of the drug’s distribution in the body after administration.
  • The ‘body clearance’ (ClB) rate, or the body’s efficiency in eliminating the drug, was measured to be about 0.061 Liters per kilogram per hour.

Evaluating the Oral Administration

  • After the drug was administered orally, the half-life of absorption was recorded as approximately 1.24 hours.
  • The ‘bioavailability’ or the proportion of the drug that enters the bloodstream and is able to have an active effect, was calculated above 100%. This high figure could be due to the uncertainty or variability in biological systems and experimentations.
  • The elimination half-life post-oral ingestion was found to be approximately 18.51 hours.

Comparative Analysis: Intravenous vs Oral Administration

The researchers concluded that the elimination half-life of theophylline after oral administration was only marginally higher than after intravenous administration. This indicates that the slow-release formulation did not significantly extend the duration of the drug’s presence within the horse’s system.

Cite This Article

APA
Errecalde JO, Landoni MF. (1992). The pharmacokinetics of a slow-release theophylline preparation in horses after intravenous and oral administration. Vet Res Commun, 16(2), 131-138. https://doi.org/10.1007/BF01839010

Publication

Veterinary research communications
ISSN: 0165-7380
NlmUniqueID: 8100520
Country: Switzerland
Language: English
Volume: 16
Issue: 2
Pages: 131-138

Researcher Affiliations

Errecalde, J O
  • Cátedra de Farmacología, Facultad de Ciencias Veterinarias, Universidad Nacional de La Plata, Argentina.
Landoni, M F

    MeSH Terms

    • Absorption
    • Administration, Oral
    • Animals
    • Biological Availability
    • Delayed-Action Preparations
    • Female
    • Half-Life
    • Horses / metabolism
    • Infusions, Intravenous / veterinary
    • Theophylline / administration & dosage
    • Theophylline / pharmacokinetics
    • Tissue Distribution

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    Citations

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