title: Contribution of passive transport mechanisms to the intestinal absorption of beta-lactam antibiotics.
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.
authors.affiliation: Department of Pharmacy, Hokkaido University Hospital, School of Medicine, Sapporo, Japan.
authors.forename: M
authors.initials: M
authors.lastname: Sugawara
authors.forename: H
authors.initials: H
authors.lastname: Saitoh
authors.forename: K
authors.initials: K
authors.lastname: Iseki
authors.forename: K
authors.initials: K
authors.lastname: Miyazaki
authors.forename: T
authors.initials: T
authors.lastname: Arita
mesh_terms: D000818:Animals; D000900:Anti-Bacterial Agents / Q000493:pharmacokinetics*; D001692:Biological Transport; D002511:Cephalosporins / Q000493:pharmacokinetics; D005947:Glucose / Q000378:metabolism; D066298:In Vitro Techniques; D007408:Intestinal Absorption; D008297:Male; D010406:Penicillins / Q000493:pharmacokinetics; D051381:Rats; D011919:Rats, Inbred Strains
chemical_list: D000900:Anti-Bacterial Agents; D002511:Cephalosporins; D010406:Penicillins; D005947:Glucose