Sodium hypochlorite, bleaching agents, and the stratum corneum.

Interactions between bleaching agents containing sodium hypochlorite (NaOCl) and human stratum corneum are complex and not fully understood. The same applies when NaOCl is used as a war gas decontaminant. In this study data yielded by in vivo testing and an ex vivo bioassay are compared. Fifteen volunteers received patch tests of a neat proprietary NaOCl bleaching agent for 15, 30, 45, 60, and 90 min. No clinical reaction was seen. Reflectance colorimetry, transepidermal water loss (TEWL), and capacitance were measured for 72 hr after patch removal. Squamometry was also performed using D-Squames and colorimetry of the samples. In addition, the ex vivo corneoxenometry bioassay was conducted on various dilutions of the bleach. Data reveal that conductance and squamometry were more sensitive than TEWL to disclose the action of bleach upon the stratum corneum. Corneoxenometry proved to be a good predictive ex vivo bioassay, indicating the same information as the in vivo tests. Both squamometry and corneoxenometry appear valuable and complementary in assessing infraclinical damages of human skin by a NaOCl bleaching agent.