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1.
Pharmacol Res Perspect ; 7(3): e00488, 2019 06.
Artigo em Inglês | MEDLINE | ID: mdl-31149343

RESUMO

In this study, we describe a novel approach for collecting bile from dogs and cynomolgus monkeys for metabolite profiling, ultrasound-guided cholecystocentesis (UCC). Sampling bile by UCC twice within 24 hours was well tolerated by dogs and monkeys. In studies with atorvastatin (ATV) the metabolite profiles were similar in bile obtained through UCC and from bile duct-cannulated (BDC) dogs. Similar results were observed in UCC and BDC monkeys as well. In both monkey and dog, the primary metabolic pathway observed for ATV was oxidative metabolism. The 2-hydroxy- and 4-hydroxyatorvastatin metabolites were the major oxidation products, which is consistent with previously published metabolite profiles. S-cysteine and glucuronide conjugates were also observed. UCC offers a viable alternative to bile duct cannulation for collection of bile for metabolite profiling of compounds that undergo biliary excretion, given the similar metabolite profiles in bile obtained via each method. Use of UCC for metabolite profiling may reduce the need for studies using BDC animals, a resource-intensive model.

2.
AAPS J ; 19(6): 1878-1889, 2017 11.
Artigo em Inglês | MEDLINE | ID: mdl-29019117

RESUMO

In the present investigations, we evaluate in vitro hepatocyte uptake and partitioning for the prediction of in vivo clearance and liver partitioning. Monkeys were intravenously co-dosed with rosuvastatin and bosentan, substrates of the organic anion transporting polypeptides (OATPs), and metformin, a substrate of organic cation transporter 1 (OCT1). Serial plasma and liver samples were collected over time. Liver and plasma unbound fraction was determined using equilibrium dialysis. In vivo unbound partitioning (Kpu,u) for rosuvastatin, bosentan, and metformin, calculated from total concentrations in the liver and plasma, were 243, 553, and 15, respectively. A physiologically based pharmacokinetic monkey model that incorporates active and passive hepatic uptake was developed to fit plasma and liver concentrations. In addition, a two-compartment model was used to fit in vitro hepatic uptake curves in suspended monkey hepatocyte to determine active uptake, passive diffusion, and intracellular unbound fraction parameters. At steady-state in the model, in vitro Kpu,u was determined. The results demonstrated that in vitro values under-predicted in vivo active uptake for rosuvastatin, bosentan, and metformin by 6.7-, 28-, and 1.5-fold, respectively, while passive diffusion was over-predicted. In vivo Kpu,u values were under-predicted from in vitro data by 30-, 79-, and 3-fold. In conclusion, active uptake and liver partitioning in monkeys for OATP substrates were greatly under-predicted from in vitro hepatocyte uptake, while OCT-mediated uptake and partitioning scaled reasonably well from in vitro, demonstrating substrate- and transporter-dependent scaling factors. The combination of in vitro experimental and modeling approaches proved useful for assessing prediction of in vivo intracellular partitioning.


Assuntos
Fígado/metabolismo , Transportadores de Ânions Orgânicos/fisiologia , Transportador 1 de Cátions Orgânicos/fisiologia , Animais , Bosentana , Macaca fascicularis , Metformina/farmacocinética , Modelos Biológicos , Rosuvastatina Cálcica/farmacocinética , Sulfonamidas/farmacocinética
3.
Drug Metab Dispos ; 43(11): 1788-94, 2015 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-26341276

RESUMO

Unbound plasma concentrations may not reflect those in target tissues, and there is a need for methods to predict tissue partitioning. Here, we investigate the unbound liver partitioning (Kpu,u) of rosuvastatin, a substrate of hepatic organic anion transporting peptides, in cynomolgus monkeys and compare it with that determined using hepatocytes in vitro. Rosuvastatin (3 mg/kg) was administered orally to monkeys and plasma and liver (by ultrasound-guided biopsy) collected over time. Uptake into monkey hepatocytes was evaluated up to steady state. Binding in monkey plasma, liver, and hepatocytes was determined using equilibrium dialysis. Mean in vivo Kpu,u was 118 after correcting total liver partitioning by plasma and liver binding. In vitro uptake data were analyzed by compartmental modeling to determine active uptake clearance, passive diffusion, the intracellular unbound fraction, and Kpu,u. In vitro Kpu,u underpredicted that in vivo, resulting in the need for an empirical in vitro to in vivo scaling factor of 10. Adjusting model parameters using hypothetical scaling factors for transporter expression and surface area or assuming no effect of protein binding on active transport increased partitioning values by 1.1-, 6-, and 9-fold, respectively. In conclusion, in vivo rosuvastatin unbound liver partitioning in monkeys was underpredicted using hepatocytes in vitro. Modeling approaches that allow integrating corrections from passive diffusion or protein binding on active uptake could improve the estimation of in vivo intracellular partitioning of this organic anion transporting peptide substrate. A similar assessment of other active hepatic transport mechanisms could confirm and determine the extent to which limited accumulation in isolated hepatocytes needs to be considered in drug development.


Assuntos
Hepatócitos/efeitos dos fármacos , Hepatócitos/metabolismo , Rosuvastatina Cálcica/metabolismo , Rosuvastatina Cálcica/farmacologia , Animais , Feminino , Previsões , Células HEK293 , Humanos , Macaca fascicularis , Masculino , Ligação Proteica/fisiologia
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