Uptake and Permeability Studies to Delineate the Role of Efflux Transporters.

Chemotherapy is one of the major therapeutic interventions in oncology. Despite numerous advances and intensive research, a large number of patients acquire multidrug resistance (MDR) and no longer respond to chemotherapy. Efflux transporters play a predominant role in mediating MDR. Cellular accumulation (uptake) and permeability studies serve as invaluable methods to detect drug efflux/transport mechanism. These methods are generally performed on transfected cells (e.g., MDCKII-MDR1, MDCKII-MRP2, and MDCKII-BCRP) or cells expressing high amount of intrinsic efflux transporters (Caco-2) utilizing specific inhibitors as positive controls. This chapter presents a method of performing uptake and permeability studies, including the preparation of various buffers required for the study.