ASSESSMENT OF AN IN VITRO HUMAN VAGINAL EPITHELIAL MODEL FOR PREDICTING VAGINAL IRRITATION.

Currently, the vaginal irritation potential of chemical ingredients and finished products is assessed using the in vivo rabbit irritation model. A viable in vitro method would be of great value to the personal care industry. In this study, the EpiVaginal™ reconstructed human epithelial model was evaluated for its ability to predict vaginal irritation of six surfactants commonly used in personal care products. After completing a range-finding study for toxicity, the tissues were exposed to various concentrations of each surfactant for 3, 6, 24 and 48 hr. Cell viability was assessed by MTT and LDH release, while the pro-inflammatory response was determined by IL-1α and PGE2 release. The positive control (1% Triton X-100) resulted in an ET50 of< 3 hr and also increases in the release of LDH (44-fold) and IL-1α (> 500 pg/ml ). PGE2 was relatively unaffected. Exposure to 0.5% SDS, 1% sodium monolaurate and 1% nonoxynol-9 resulted in a loss of viability with an ET50 of < 3 hr with increases in the release of LDH (> 34 fold) and IL-1α (296 to > 500 pg/mL). PGE2 release was also observed, except with exposure to nonoxynol-9. Exposure to 0.1% benzalkonium chloride and MASIL® SF-19 resulted in an ET50 of 5.2 and 6.4 hr, respectively, with LDH release increasing to > 20-fold by 6 hr. A time-dependent increase in IL-1α release (> 500 pg/ml ) and PGE2 release was observed, though benzalkonium chloride had a much more significant effect on PGE2 release (1184 pg/ml ) than MASIL® (486 pg/ml). Finally, tissues exposed to 10% Cremophor® EL remained relatively unaffected (ET50 > 48 hr) with LDH and IL-1α and release comparable to negative control (PBS). PGE2 release was also comparable to negative control until 48 hr exposure (749 pg/ml). Overall, these surfactants produced a time dependent increase in markers of vaginal irritation that were consistent with the in vivo model. These data suggest that the EpiVaginal™ system may be a suitable in vitro model to assess the vaginal irritation potential of common consumer product ingredients.

EpiVaginal™, IL-1α, LDH release, MTT assay, PGE2, Vaginal irritation, VEC-100

1% Triton X-100, Benzalkonium chloride (0.1%), Cremophor EL (10%), MASIL SF-19 (1%), Nonoxynol-9 (1%), Sodium dodecyl sulfate (0.5%), Sodium Monolaurate (1%)