On the time-dependence of amphiphile-induced haemolysis.

The time-course of haemolysis induced by alkyltrimethylammonium bromides, alkyl sulphates, octaethyleneglycol alkyl ethers, and ZWITTERGENT detergents (C10-C16) was studied. A considerable lag in the development of haemolysis was observed for the C10 and C12 derivatives. The lag exceeded 30 min at low or moderate concentrations of the surfactants. Most of the C14 and C16 derivatives showed no lag but the time-course of the haemolytic reaction of these derivatives indicated biphasic kinetics of haemolysis. With those surfactants showing a lag the critical micelle concentration (cmc) of the surfactants was above the concentrations used in the experiments, whereas cmc in the case of those surfactants showing no lag was close to or slightly below. It is concluded that the differences in the time-course of the haemolytic reaction shown by different derivatives are not connected with the occurrence of micelles in the bulk solution, but that the differences in time-course of the haemolytic reaction reflect differences in the rate of those changes in the membrane molecular organization which precede haemolysis.