FIG. 2.

Density gradient analysis of [¹⁴C]E5531 binding to plasma components. [¹⁴C]E5531 (341 nM), prepared as described in the Materials and Methods section, was incubated at 37°C for 18 h in HBSS or freshly prepared plasma and was fractionated by density gradient analysis with self-forming iodixanol gradients. Analysis of the radioactivity in the gradients containing drug incubated with HBSS (○) or with plasma (●), as well as analysis of the cholesterol content of the fractionated plasma (□), was performed as described in the Materials and Methods section.