PLASMA PROTEIN BINDING OF DRUGS

1. Equilibrium dialysis, ultracentrifugation, and gel filtration on Sephadex are pointed out as being the most commonly used methods of quantitative determination of drug protein binding. 2. The interaction between proteins and substances of low molecular weight is governed by the law of mass action. It is the basis for the description of the results of binding experiments. The plotting of the data according to Scatchard (1949) is considered the most useful method. Also methods of plotting described by Scholtan (1962) and Krüger-Thiemer (1961) are used and offer advantages for special problems. 3. The binding of drugs to plasma proteins seems to take place mainly by hydrophobic mechanisms. The aromatic rings of the drugs apparently play an important part in their binding to proteins. 4. The bound drugs influence the structure of the proteins. 5. The binding of drugs to plasma proteins influences their action, tissue distribution, metabolism, and renal elimination. 6. The drug binding ability of plasma proteins can be changed in pathologic conditions. 7. Drugs can displace other drugs or physiological substances of low molecular weight from their binding sites on plasma proteins. © 1969 Springer-Verlag.