Non-linear intestinal absorption kinetics of cefadroxil in the rat.
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.
Sánchez-Picó
A
A
Department of Pharmacology and Pharmacetics, Faculty of Pharmacy, University of Valencia, Spain.
Peris-Ribera
J E
JE
Toledano
C
C
Torres-Molina
F
F
Casabó
V G
VG
Martín-Villodre
A
A
Plá-Delfina
J M
JM
D000818:Animals; D002434:Cefadroxil / Q000493:pharmacokinetics*; D007408:Intestinal Absorption; D007421:Intestine, Small / Q000378:metabolism; D008297:Male; D010477:Perfusion; D051381:Rats; D011919:Rats, Inbred Strains
D002434:Cefadroxil