Safety evaluation of some humectants and moisturizers used in cosmetic formulations

Synopsis Safety tests have been carried out on some humectants and moisturizers, continuing a study involving commonly used cosmetic ingredients (1-6). The test substances (listed in Table I) were products from various suppliers and of different types and grades. The ocular and cutaneous tolerance tests have been conducted on animals following the official French methods but with some complements or modifications (28-36). Each compound has been tested as supplied and diluted in water. Pathological lesions of the ocular mucous membrane were provoked by lactic acid at 20 and 10% concentrations. A slight corneal opacity was also noted with ethoxydiglycol and polyamino sugar condensate and a significant irritation with hexylene glycol (non-diluted). In dilutions of 10 or 20%, these substances were non-irritating. Only one product (lactic acid) has given a moderate primary cutaneous irritation (PII = 2.50), when applied undiluted. The indices obtained with the other raw materials correspond to a non-irritating application. With the exception of lactic acid (the study being terminated after 1 week), no significant adverse reaction was macroscopically and histologically observed after daily application (neat) for 6 weeks. Finally, the predictive sensitizing tests (guinea-pig) carried out with two samples of propylene glycol proved to be negative.