Rosuvastatin Liver Partitioning in Cynomolgus Monkeys: Measurement In Vivo and Prediction Using In Vitro Monkey Hepatocyte Uptake

Abstract

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 (Kp u,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 ultrasoundguided 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 Kp u,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 Kp u,u . In vitro Kp u,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.

A Study on Pharmacokinetics of Bosentan with Systems Modeling, Part 2: Prospectively Predicting Systemic and Liver Exposure in Healthy Subjects

“…Toward a prospective in vitro to in vivo extrapolation (IVIVE), Li et al (2014b) developed an approach simultaneously leveraging data from multiple training compounds in empirical scaling factor estimation (e.g., global scaling factors that are not compound independent), assuming that substrates of the same or similar transporters share the same scaling factor. Animal studies are still an option for transporter substrates' PK predictions (Morse et al, 2015), particularly in understanding liver exposure, as global scaling factor estimations were based on systemic PK rather than liver concentration. However, the use of traditional interspecies scaling oversimplifies the physiologic differences among species, and direct measurement in terminal or biopsy studies to understand tissue concentrations can be ambiguous and potentially misleading due to improper data interpretation or species differences in tissue exposure.…”

Coproporphyrins I and III as Functional Markers of OATP1B Activity: In Vitro and In Vivo Evaluation in Preclinical Species

“…Cryopreserved human (Lot NRJ) and cynomolgus monkey hepatocytes (Lot DQA) were processed in a stepwise manner, according to the instructions provided by the manufacturer (BioreclamationIVT). The uptake studies of CPs I and III were conducted as described previously (Morse et al, 2015). In brief, hepatocytes were incubated with the preprepared Krebs-Henseleit buffer containing CP isomers (1 mM) or RSV (1 mM, positive control) with or without RIF (as the OATP inhibitor, 100 mM, respectively).…”

Determination of Unbound Partition Coefficient and in Vitro-in Vivo Extrapolation for SLC13A Transporter-Mediated Uptake

“…In vitro hepatocyte systems tend to underestimate in vivo K puu for OATP substrates (Morse et al, 2015), and typically, scaling factors are needed to more accurately predict in vivo outcomes (Li et al, 2014). However, in this case, the in vitro cryopreserved-suspension rat hepatocyte system appears to be able to predict in vivo rat K puu reasonably well.…”