The correlation between drug binding to the human erythrocyte and its hemolytic activity

Cationic phenothiazine derivatives, anionic anthranilic acid derivatives and fluorescent probe 1-anilino-8-naphthalene sulfonate (ANS) which had hemolytic activities were used to investigate hemolysis of human erythrocyte. The observed hemolytic activities of drugs could divided into two categories: (1) the difference of the binding activity of drugs to the erythrocyte and (2) the difference of the membrane perturbation activity of drugs bound to the erythrocyte. The human erythrocyte had two kinds of binding sites for any drug used. The first site of them was already saturated before hemolysis occurred and the second site of them may play an important role in hemolysis by these drugs.