The Comparative Effect of Chlorhexidine and Cetrimonium Bromide on Erythrocyte Membranes

Abstract

The effect of chlorhexidine (Chx) and cetrimonium bromide (Ctab) on the haemolysis of erythrocytes has been studied. A concentration dependent release of haemoglobin was observed in isotonic media, with total haemolysis at 80 nmol Chx per 107 cells and 20 nmol Ctab per 107 cells. The rate of haemolysis induced by Chx shows a biphasic pattern in contrast to the uniphasic pattern of Ctab. In concentrations below 10 nmol per 107 cells, Chx produces more haemolysis than Ctab whereas the opposite effect is observed at higher concentrations. Chx and Ctab stabilize the erythrocyte membrane against hypotonic shock. The concentrations of Chx and Ctab giving maximal stabilization are 0.25 nmol per 107 cells and 2 nmol per 107 cells respectively. The normal biconcave disc form of the erythrocytes is converted to cup forms and in‐vaginated spheres by Chx and Ctab. The binding of Chx to erythrocytes in isotonic media increases linearly with the total concentration up to about 25 nmol Chx per 107 cells where the curve has a point of inflection. With more than 25 nmol Chx per 107 cells the amount of Chx bound again increases linearly up to 120 nmol per 107 cells. The slope of the curve above the point of inflection is approximately 4 times that of the curve below this point. No level of saturation of the binding is observed at the concentrations of Chx used in this study. The mode of action of Chx on erythrocyte membranes is discussed in the light of the present results.