Use of uptake intrinsic clearance from attached rat hepatocytes to predict hepatic clearance for poorly permeable compounds

Abstract

1. We previously reported that the accuracy of clearance (CL) prediction could be differentiated by permeability. CL was drastically under-predicted by in vitro metabolic intrinsic clearance (CL_int) for compounds with low permeability (<5 × 10⁻⁶ cm/s).

2. We determined apparent uptake CL_int by measuring initial disappearance from medium using attached rat hepatocytes and metabolic CL_int by measuring parent depletion in suspended rat hepatocytes (cells and medium).

3. Uptake and metabolic CL_int were comparable for highly permeable metabolic marker compounds. In contrast, uptake CL_int was 3- to 40-fold higher than metabolic CL_int for rosuvastatin, bosentan, and 15 proprietary compounds, which had low permeability, suggesting that uptake could be a rate-determining step in hepatic elimination for these poorly permeable compounds.

4. The prediction of hepatic CL was improved significantly when using uptake CL_int for the compounds with low permeability. The average fold error was 2.2 and 6, as opposed to >11 and >47 by metabolic CL_int, with and without applying a scaling factor of 4, respectively.

5. Uptake CL_int from attached hepatocytes can be used as an alternative approach to predict hepatic clearance and to understand the significance of hepatic uptake in elimination in an early drug discovery setting.

Keywords::

• Permeability
• clearance prediction
• OATP
• scaling factor

Acknowledgments

We thank Department of Medicinal Chemistry, Amgen, Cambridge, MA, for compound synthesis. We also thank Lei Cao for plasma CL data of compounds 4 and 5, Dr. Adria Colletti and Meghan Langley for their contribution to in vivo pharmacokinetic studies and Dr. Zhiyang Zhao for his insightful scientific review and comments of the manuscript.

Declaration of interest

The authors report no declarations of interest.