Quantitative Analysis of Intracellular Drug Concentrations in Hepatocytes

Abstract

Knowledge of intracellular drug concentrations in hepatocytes is fundamentally important for understanding and predicting drug efficacy, toxicity, drug–drug interactions (JJB - DDIs) and intersubject variability in drug response. This chapter will focus on measurement of unbound intracellular concentrations in hepatocytes, consistent with the “free-drug hypothesis.” Metabolism and transport processes in the liver frequently play an important role in determining hepatic intracellular drug concentrations. In this chapter, we will comprehensively describe two methods used to quantify unbound hepatic intracellular drug concentrations using isolated perfused livers and in vitro sandwich-cultured hepatocytes. We will discuss challenges, assumptions, and technical considerations for experimental design, and provide protocols for measuring intracellular unbound drug concentrations and subcellular distribution of xenobiotics in sandwich-cultured hepatocytes and in isolated perfused livers. Additionally, some emerging tools and technologies will be explored briefly.