Heroin and Morphine Binding with Human Serum Proteins and Red Blood Cells 1

Abstract

Summary

Equilibrium dialysis experiments were performed to determine the binding properties of heroin and morphine to major blood constituents. The serum proteins studied showed little binding with heroin-¹⁴C or morphine-¹⁴C.

However, the addition of cold heroin to the system increased the observed uptake of the radioactive substance with serum, RBC, ghosts, and washed RBC. These changes in binding may be due to mechanical affinity of the molecules: ¹⁴C-labeled plus nonradioactive in vitro. Conjugation may alter this pattern in vivo. Free heroin and morphine probably float unbound in the blood before further metabolism in other tissues.