title: Application of permeability-limited physiologically-based pharmacokinetic models: part I-digoxin pharmacokinetics incorporating P-glycoprotein-mediated efflux.
abstract: A prerequisite for the prediction of the magnitude of P-glycoprotein (P-gp)-mediated drug-drug interactions between digoxin and P-gp inhibitors (e.g. verapamil and its metabolite norverapamil) or P-gp inducers (e.g. rifampicin) is a predictive pharmacokinetic model for digoxin itself. Thus, relevant in vitro metabolic, transporter and inhibitory data incorporated into permeability-limited models, such as the "advanced dissolution, absorption and metabolism" (ADAM) module and the permeability-limited liver (PerL) module, integrated with a mechanistic physiologically-based pharmacokinetic (PBPK) model such as that of the Simcyp Simulator (version 12.2) are necessary. Simulated concentration-time profiles of digoxin generated using the developed model were consistent with observed data across 31 independent studies [13 intravenous single dose (SD), 12 per oral SD and six multiple dose studies]. The fact that predicted tmax (time of maximum plasma concentration observed) and Cmax (maximum plasma concentration observed) of oral digoxin were similar to observed values indicated that the relative contributions of permeation and P-gp-mediated efflux in the model were appropriate. There was no indication of departure from dose proportionality over the dose range studied (0.25-1.5 mg). All dose normalised area under the plasma concentration-time curve profiles (AUCs) for the 0.25, 0.5, 0.75 and 1 mg doses resembled each other. Thus, PBPK modelling in conjunction with mechanistic absorption and distribution models and reliable in vitro transporter data can be used to assess the impact of dose on P-gp-mediated efflux (or otherwise).
authors.affiliation: Simcyp Limited (a Certara company), Blades Enterprise Centre, John Street, Sheffield S2 4SU, UK. S.Neuhoff@simcyp.com
authors.forename: Sibylle
authors.initials: S
authors.lastname: Neuhoff
authors.forename: Karen Rowland
authors.initials: KR
authors.lastname: Yeo
authors.forename: Zoe
authors.initials: Z
authors.lastname: Barter
authors.forename: Masoud
authors.initials: M
authors.lastname: Jamei
authors.forename: David B
authors.initials: DB
authors.lastname: Turner
authors.forename: Amin
authors.initials: A
authors.lastname: Rostami-Hodjegan
mesh_terms: D020168:ATP Binding Cassette Transporter, Subfamily B, Member 1 / Q000378:metabolism*; D000284:Administration, Oral; D000818:Animals; D000889:Anti-Arrhythmia Agents / Q000008:administration & dosage / Q000378:metabolism / Q000493:pharmacokinetics*; D003198:Computer Simulation; D004077:Digoxin / Q000008:administration & dosage / Q000378:metabolism / Q000493:pharmacokinetics*; D006801:Humans; D007413:Intestinal Mucosa / Q000378:metabolism; D008099:Liver / Q000378:metabolism; D008954:Models, Biological; D010539:Permeability
chemical_list: D020168:ATP Binding Cassette Transporter, Subfamily B, Member 1; D000889:Anti-Arrhythmia Agents; D004077:Digoxin
keywords: ABCB1; IVIVE; MDR1; P-glycoprotein; digoxin; pharmacokinetics; simulation; transporter