Biological and Pharmaceutical Bulletin
Online ISSN : 1347-5215
Print ISSN : 0918-6158
ISSN-L : 0918-6158
Utility of Gastrointestinal Physiology Regulated-Dogs : Bioavailability Study of a Commercial sustained-Release Dosage Form of Theophylline
Kazuyoshi SAGARAMiwako KAWATAHiroaki MIZUTAMasahiro SHIBATA
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1994 Volume 17 Issue 7 Pages 931-934


The utility of gastrointestinal physiology regulated-dogs (regulated-dogs) was evaluated in a bioavailability study. The gastrointestinal physiology of beagle dogs was regulated with a combined-treatment of intramuscular pentagastrin and intravenous atropine sulfate. Theophylline has been regarded as a drug that is absorbed completely in the entire gastrointestinal tract but slowly in the colon for humans. A commercial sustained-release tablet (SR tablet) of theophylline and a commercial conventional tablet of aminophylline (theophylline hemiethilenediamine salt) were chosen as model preparations in this study. In the regulated-dogs, the drug absorption was almost complete for the conventional tablet. The bioavailability of the SR table accounted for 76% in the regulated-dogs and 71% in intact dogs relative to that of the conventional tablet in the regulated-dogs, respectively, but no significant difference was detectable between these values. An advantage of the regulated-dogs over the intact dogs was, however, revealed in the time-profiles of the cumulative percentage of theophylline absorbed from the SR tablet, suggesting a modification of drug absorption by the prolonged arrival of the tablet to the colon.

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