Relative systemic availability of sulfapyridine from commercial enteric-coated and uncoated sulfasalazine tablets.
The absorption of sulfapyridine after a single 2.0-Gm oral dose of sulfasalazine, the drug of choice in the treatment of inflammatory bowel disease, as commercial uncoated and enteric-coated and uncoated tablets was evaluated in four healthy male adults. The peak plasma concentration of sulfapyridine after the enteric-coated tablets occurred at 20 hours on the average (compared to 14 hours for the uncoated tablets) and was only 50% of that attained from the uncoated tablets (P less than 0.05). The low relative extent of systemic availability of sulfapyridine from the enteric-coated tablets (65.5 +/- 6.3 per cent, mean +/- S.E.) compared to uncoated tablets may be due to absorption rate-dependent presystemic metabolism, since the relative extent of sulfapyridine absorption was 92.7 +/- 6.2 per cent compared to uncoated tablets. These findings suggest that enteric-coated and uncoated tablets of sulfasalazine are not bioequivalent. It remains to be determined whether the clinical efficacy of sulfasalazine from enteric-coated tablets is affected.
D000328:Adult; D001682:Biological Availability; D006801:Humans; D007408:Intestinal Absorption; D008297:Male; D012995:Solubility; D013424:Sulfanilamides / Q000378:metabolism*; D013427:Sulfapyridine / Q000097:blood / Q000378:metabolism*; D012460:Sulfasalazine / Q000008:administration & dosage / Q000378:metabolism*; D013607:Tablets; D013608:Tablets, Enteric-Coated; D013997:Time Factors
D013424:Sulfanilamides; D013607:Tablets; D013608:Tablets, Enteric-Coated; D012460:Sulfasalazine; D013427:Sulfapyridine