Contribution of passive transport mechanisms to the intestinal absorption of beta-lactam antibiotics

J Pharm Pharmacol. 1990 May;42(5):314-8. doi: 10.1111/j.2042-7158.1990.tb05418.x.

Abstract

The transport characteristics of aminopenicillins (ampicillin and amoxicillin), aminocephalosporins (cephalexin, cephradine and cefadroxil) and cefazolin have been compared with those of an actively transported substance (D-glucose) and a passively transported substance (L-glucose). Although the initial uptake of the aminocephalosporins was stimulated in the presence of an inward H+ gradient, there was no overshoot in the uptake of any of the drugs tested, even in the presence of an H+ gradient. Also, the time course and the degree of uptake of these drugs were similar to those of L-glucose, especially in the absence of an H+ gradient. These results suggest that the beta-lactam antibiotics tested, like L-glucose, pass through the rat intestinal brush border membrane mainly by passive diffusion. However, the differences in absorption between these drugs, like the differences in their disappearance from a proximal loop of rat intestine, cannot be explained by a simple permeation process alone.

MeSH terms

  • Animals
  • Anti-Bacterial Agents / pharmacokinetics*
  • Biological Transport
  • Cephalosporins / pharmacokinetics
  • Glucose / metabolism
  • In Vitro Techniques
  • Intestinal Absorption*
  • Male
  • Penicillins / pharmacokinetics
  • Rats
  • Rats, Inbred Strains

Substances

  • Anti-Bacterial Agents
  • Cephalosporins
  • Penicillins
  • Glucose