Characteristics of cefdinir uptake by rabbit small intestinal brush-border membrane vesicles.
Aminocephalosporins with peptide-like structures have been shown to be absorbed by the intestinal peptide carrier. We investigated the transport mechanism of cefdinir, an oral monocarboxylic acid cephalosporin, using rabbit small intestinal brush-border membrane vesicles. Transport of cefdinir showed a slow and almost linear uptake rate for concentrations up to 30 mM with and without and inward H+ gradient. No overshoot phenomenon was observed in the presence of an inward H+ gradient. The uptake rate increased only slightly with decreasing extravesicular pH, and a protonophore had little effect on the uptake. Aminocephalosporins such as cephalexin only slightly inhibited cefdinir uptake even in the presence of an inward H+ gradient, and vice-versa. Monocarboxylic acids such as acetic acid and salicylic acid had little effect on cefdinir uptake. These findings suggest that in contrast with other oral cephalosporins cefdinir uptake through the brush-border membrane is slow and involves a mechanism similar to passive diffusion.
Kitagawa
S
S
Niigata College of Pharmacy, Japan.
Sugaya
Y
Y
Kaseda
Y
Y
Sato
S
S
D000818:Animals; D002264:Carboxylic Acids / Q000494:pharmacology; D000077525:Cefdinir; D002511:Cephalosporins / Q000493:pharmacokinetics* / Q000494:pharmacology; D004347:Drug Interactions; D006863:Hydrogen-Ion Concentration; D066298:In Vitro Techniques; D007408:Intestinal Absorption / Q000187:drug effects; D007421:Intestine, Small / Q000378:metabolism* / Q000648:ultrastructure*; D007700:Kinetics; D008871:Microvilli / Q000378:metabolism; D011817:Rabbits; D013696:Temperature
D002264:Carboxylic Acids; D002511:Cephalosporins; D000077525:Cefdinir