title: Non-linear intestinal absorption kinetics of cefadroxil in the rat.
abstract: Absorption of cefadroxil in a selective intestinal absorption area (the proximal third of the small intestine) of the anaesthetized rat, at seven initial perfusion concentrations, ranging from 0.01 to 10.0 mg mL-1, is shown to be a non-linear transport mechanism. With the aid of computer-fitting procedures based on differential and integrated forms of Michaelis-Menten equation, Vm and Km values of 36.7-37.3 mg h-1 and 12.0-13.0 mg, respectively, were found. The statistical parameters were better than those obtained both for first-order and for combined Michaelis-Menten and first-order kinetics. There is no evidence for substantial passive diffusion processes. The results reported here, together with allometric considerations and literature data analysis, may help to explain some particular non-linear features of plasma level curves associated with the administration of fairly high oral doses of cefadroxil to humans.
authors.affiliation: Department of Pharmacology and Pharmacetics, Faculty of Pharmacy, University of Valencia, Spain.
authors.forename: A
authors.initials: A
authors.lastname: Sánchez-Picó
authors.forename: J E
authors.initials: JE
authors.lastname: Peris-Ribera
authors.forename: C
authors.initials: C
authors.lastname: Toledano
authors.forename: F
authors.initials: F
authors.lastname: Torres-Molina
authors.forename: V G
authors.initials: VG
authors.lastname: Casabó
authors.forename: A
authors.initials: A
authors.lastname: Martín-Villodre
authors.forename: J M
authors.initials: JM
authors.lastname: Plá-Delfina
mesh_terms: D000818:Animals; D002434:Cefadroxil / Q000493:pharmacokinetics*; D007408:Intestinal Absorption; D007421:Intestine, Small / Q000378:metabolism; D008297:Male; D010477:Perfusion; D051381:Rats; D011919:Rats, Inbred Strains
chemical_list: D002434:Cefadroxil