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Nonlinear pharmacokinetics of hepatobiliary transport of rose bengal in rats after iv bolus administration with varying doses
Author(s) -
Wang Huan Kui,
Miyachi Seiji,
Yamazaki Masayo,
Sawada Yasufumi,
Chung Youn Bok,
Iga Tatsuji,
Hanano Manabu,
Sugiyama Yuichi
Publication year - 1992
Publication title -
biopharmaceutics and drug disposition
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.419
H-Index - 58
eISSN - 1099-081X
pISSN - 0142-2782
DOI - 10.1002/bdd.2510130903
Subject(s) - pharmacokinetics , excretion , chemistry , medicine , endocrinology , bolus (digestion) , elimination rate constant , biochemistry , volume of distribution
Abstract To investigate the nonlinear kinetics in the hepatobiliary transport of rose bengal (RB), the time profiles of plasma concentration and biliary excretion rate after its i.v. administration at various doses were measured in rats. The total body clearance decreased remarkably with increased dose. The hepatic uptake clearance also showed a similar dose dependency, and saturation of hepatic uptake at least partly accounts for the dose‐dependent change in total body clearance. The peak biliary excretion rate approached the transport maximum (approximately 150 nmol min −1 kg −1 ) with increased dose. To further clarify which process in RB hepatobiliary transport has nonlinearity, we analysed thus obtained data based on a three‐compartment model. The hepatic uptake and sequestration rate constants decreased remarkably with increased dose. The initial hepatic uptake rates assessed from the plasma disappearance rate during the early phase fit well to the Michaelis‐Menten equation with a saturable and a nonsaturable component. The maximum uptake velocity and Michaelis constant were 4·7 μmol min −1 kg −1 and 360 μM, respectively. That hepatic uptake has a much higher capacity (about 30 fold) than biliary excretion suggests that biliary excretion can be a rate‐determining process in the overall hepatobiliary transport of RB. We conclude that the saturation of both hepatic uptake and biliary excretion could be the main causes for the nonlinear pharmacokinetics of hepatobiliary transport of RB.