INTERACTION OF PHENOTHIAZINE DERIVATIVES WITH BOVINE SERUM ALBUMIN

1. The degree of binding of acepromazine, promazine, methopromazine, chlorpromazine and triflupromazine to bovine serum albumin was determined by gel filtration on Sephadex columns. 2. Some characteristics of this type of binding are given. These are the proportion of the drug bound, the overall binding constant K1, the apparent binding constant k+, and the free energy ΔF0. The binding capacity of a 1% solution of bovine serum albumin for different phenothiazines increases in the order given above. 3. The partition coefficients (n-heptane/buffer solution pH 7.4) are correlated to the degree of protein binding only in some of the compounds studied. 4. The protein binding of promazine varies with the pH of the solution especially in the range of pH 6.8 to 8.0. 5. The ways of presenting the results of binding experiments as well as the influence of various substituents and of the pH of the solution are discussed. © 1969 Springer-Verlag.