[Effect of histamine on dimedrol interaction with human serum albumin].

It has been established by equilibrium dialysis and ultraviolet difference spectrophotometry that at pH 6.8 diphenhydramine interacts with human serum albumin more actively. It has been demonstrated that on the molecule of human serum albumin diphenhydramine interacts with two types of independent binding sites. The effects of pH and ionic strength of the medium, temperature, and cations on diphenhydramine binding with human serum albumin indicate that the drug is bound by hydrophobic interaction to the first type of the binding site and by van der Waals' forces to the second type of the binding site. Interaction of diphenhydramine with the second type of the binding site involves B conformation of human serum albumin. The presence of histamine increases diphenhydramine binding to human serum albumin via the second type of the binding site.