Lysis of human red blood cells. 3: Effect of contact time on surfactant-induced hemolysis.

The percent hemolysis induced by various surfactants was determined as a function of the formulation composition and formulation: blood contact time using the dynamic in vitro method of Krzyzaniak et al. (1). The amount of hemolysis induced by nonionic surfactant formulations is shown to be relatively low and to increase only slightly with contact time. However, when ionic surfactant formulations are used, hemolysis is shown to increase dramatically with surfactant concentration and to be sigmoidally related to the logarithm of contact time. Since surfactant-induced hemolysis is dependent on both the surfactant concentration and the contact time, intravascular hemolysis must be evaluated using an in vitro method that simulates the intravenous injection site. With this information, hemolytically safe surfactant formulations can be developed for intravenous administration.