title: Disposition of glycyrrhizin in the perfused liver of rats.
abstract: The disposition of glycyrrhizin (GLZ) in the perfused liver of rats after dosing in the range of 0.5-30.0 mg was investigated and a pharmacokinetic model was devised to interpret the results. The uptake rate of GLZ into the liver with respect to the unbound GLZ concentration (Cf) in the perfusate followed a Michaelis-Menten type equation with a Km,up of 1.17 micrograms/ml and Vmax,up of 13.9 micrograms/min/g of liver. The efflux clearance (0.044 ml/min/g of liver) from the liver was independent of the Cf in the liver. The biliary excretion rate at a steady-state Cf level in the liver followed a Michaelis-Menten type equation with a substrate inhibition constant (Ki,B) of 42.3 micrograms/ml, Km,B of 1.68 micrograms/ml, and Vmax,B of 3.11 micrograms/min/g of liver. The proposed model, with the holding time fitted to biliary excretion at each dose, accurately described both the perfusate concentration-time profile and the cumulative biliary excretion profile.
authors.affiliation: Faculty of Pharmaceutical Sciences, Tokushima Bunri University, Japan.
authors.forename: S
authors.initials: S
authors.lastname: Ishida
authors.forename: Y
authors.initials: Y
authors.lastname: Sakiya
authors.forename: Z
authors.initials: Z
authors.lastname: Taira
mesh_terms: D000818:Animals; D001646:Bile / Q000378:metabolism; D006034:Glycyrrhetinic Acid / Q000031:analogs & derivatives* / Q000493:pharmacokinetics; D019695:Glycyrrhizic Acid; D008099:Liver / Q000378:metabolism*; D008297:Male; D008657:Metabolic Clearance Rate; D008954:Models, Biological; D010477:Perfusion; D011485:Protein Binding; D051381:Rats; D017208:Rats, Wistar; D012709:Serum Albumin / Q000378:metabolism
chemical_list: D012709:Serum Albumin; D019695:Glycyrrhizic Acid; D006034:Glycyrrhetinic Acid