The predominant role of surfactants in the modulation of toxicity of detergent products: An in vitro analysis of shampoos

20 shampoos and their component surfactants were studied in vitro using a murine epidermal cell line (HEL/30). Lactate dehydrogenase (LDH) leakage into the cell medium and the inhibition of protein neosynthesis were evaluated as markers of cytotoxicity after 2 hr of exposure. The coefficients of correlation were -0.83 and -0.69 for comparisons between total surfactant content and inhibition of protein synthesis and leakage of LDH, respectively. There was an inverse relationship between the inhibition of protein synthesis and the amphoteric surfactant content of the shampoo. An excellent correlation (r = 0.94) was found between LDH leakage values and scores from eye irritation tests in vivo on seven of the shampoos. The results obtained suggest that this model allows quantitative evaluation of the cytotoxicity of detergent products (shampoos) and of the contribution of their major components (surfactants) to that toxicity.