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The pharmacokinetics of meclofenamic acid in the horse
Author(s) -
SNOW D. H.,
BAXTER P.,
WHITING B.
Publication year - 1981
Publication title -
journal of veterinary pharmacology and therapeutics
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.527
H-Index - 60
eISSN - 1365-2885
pISSN - 0140-7783
DOI - 10.1111/j.1365-2885.1981.tb00724.x
Subject(s) - pharmacokinetics , chemistry , volume of distribution , bioavailability , absorption (acoustics) , horse , pharmacology , sodium , distribution (mathematics) , medicine , biology , paleontology , mathematical analysis , physics , mathematics , organic chemistry , acoustics
The pharmacokinetics of meclofenamic acid were studied in Thoroughbred horses and in ponies. After intravenous (i.v.) administration of either 2 mg/kg or 4 mg/kg sodium meclofenamate the elimination half‐life was of the order of 0.9 h while the volume of distribution was found to be 0.128 litre/kg. Elimination was in accordance with a one‐compartment model. Following oral administration of either meclofenamic acid (4 mg/kg) or sodium meclofenamate (4 mg/kg) a much longer terminal half‐life than that calculated for K el from i.v. data was found. This anomaly indicated that the ‘flip‐flop’ phenomenon was present, i.e. K a exceeded K el . More rapid and higher peak levels occurred following sodium meclofenamate than meclofenamic acid, although total bioavailability was similar. Studies in ponies with meclofenamic acid showed a lower absorption than that found in Thoroughbreds. Overnight fasting before meclofenamic acid administration did not alter the rate or extent of absorption. Intramuscular administration of sodium meclofenamate resulted in low plasma concentrations and after 25 h only 46% of the drug had been absorbed.