The effects of β-diethylaminoethyl-diphenylpropylacetate (SKF 525-A) on biological membranes—I: SKF 525-A-induced stabilization of human erythrocytes

Abstract

β-Diethylaminoethyl-diphenylpropylacetate (SKF 525-A) results in either hemolysis or stabilization of the red cell membrane. These effects are concentration dependent. At higher concentrations of SKF 525-A (10 −3M), an increase in hemolysis and a decrease in osmotic resistance is noted, whereas a stabilization of the red cell membranes occurs at lower concentrations of 10 −4–10 −9M. The hemolysis of the red cell is temperature dependent and hemolysis increases as temperature decreases. The SKF 525-A action appears to be immediate and the effects prolonged. The concentration at which SKF 525-A demonstrates its greatest membrane stabilization corresponded to the first breaking point observed during measurements of surface tension, and thus perhaps indicates the formation of micelles. It can be calculated that one molecule of SKF 525-A occupied 51 Å 2 of red cell area. SKF 525-A (10 −4 M) causes a change in the mean cellular volume of red cells over all osmolar concentrations studied. One possible mechanism of action that would account for these findings is that the erythrocyte membrane expands in combination with SKF 525-A in the same way that lipid monolayers interact with various surface-active drugs such as the phenothiazine derivatives. The resulting expansion of the erythrocyte membrane would lead to an increase in the surface area and volume of the red cell and thus decrease osmotic fragility.