Standardization of an in vitro red blood cell test for evaluating the acute cytotoxic potential of tensides.

A new bovine red blood cell (RBC) test is presented as a biological in vitro assay for rapid assessment of the membrane and protein damaging effects of tensides. The system uses the hemoglobin released during RBC damage as an indicator to determine quantitatively the concentration at which the tensioactive agents affect and disrupt the plasma membrane. The spectrophotometric assay also considers the denaturation of hemoglobin caused by high concentrations of the tensides. Thus besides the halfmaximal concentrations to cause hemolysis (H50), a denaturation index (DI in %) can be determined for each test agent. The RBC assay was validated by assessing the H50 and DI for 30 randomly selected tensioactive agents from various sources and comparing the in vitro effects with their local irritant activity as assessed by the Draize test in the conjuntiva of conscious rabbits. The relationship between H50 and DI values, expressed as the lysis/denaturation ratio, was found to give a ranking order that best characterized the membrane damaging potency of the agents tested. Tensides known to possess ocular irritancy in the Draize test were characterized by a low lysis/denaturation ratio.