Bioavailability of indomethacin capsules in humans (III): Correlation with bioavailability in beagle dogs

The bioavailabilities of five indomethacin capsules were studied in ten beagle dogs and correlations with the in vivo results in humans and dissolution rates were investigated. The difference in bioavailability between two commercial products was smaller in dogs than in humans, which seemed to be due to strong disintegration forces in dogs. The difference in the dissolution rate among the products was reflected less in the Tmax in dogs than in humans, and the Tmax was shorter in dogs which seems to be due to faster gastric emptying and passage of the drug through the absorption site in dogs. Gastric acidity effects on the indomethacin availability found in humans were not observed in dogs. The Cmax and Tmax correlated well with the in vitro dissolution rates, but AUC24 did not. The Cmax and Tmax in dogs also correlated with the corresponding parameters in humans, especially those in high gastric acidity humans, but AUC24 did not.