A physical method for preservation of cosmetic products.

To date, the microbiological stability of cosmetics products is assured by means of chemical preservatives, with well-known possible side effects such as irritation or cutaneous allergic events. This paper describes a new concept to protect all types of cosmetic formulae from microbiological contamination: the osmotic effect of a particular form of glycerylpolyacrylate gels. The latter allows the formulator to conceive numerous preservative-free formulae. The basis of its activity lies in the strong osmotic properties of the hydrogel: it absorbs water from its surroundings, thus depriving germs of the vital aqueous environment needed for survival. Challenge tests on various microorganisms, repeat insult challenges and time-stability tests performed on these hydrogels in cosmetic formulas were carried out. At the same time, the hydrogel exhibited high skin moisturizing power. The hydrogel is non-toxic and non-irritant as the Primary Cutaneous Irritation Index observed after 48 h of occlusive patches in 10 adult volunteers is only of 0.10.