Differential scanning calorimetry studies on the mechanism of skin-softening effect of sodium acetylhyaluronate

A novel humectant, sodium acetylhyaluronate (AcHA), was found to have an ex cellent skin-softening effect on the stratum corneum. To clarify the mechan ism of the skin-softening effect, the hydration behavior of AcHA was invest igated by using differential scanning calorimetry (DSC). The results sugges ted that the amount of adsorbed water of AcHA in powder form was equal to t hat of HA. However, the DSC results showed that the bound water content in the stratum corneum treated with AcHA was markedly greater than that of HA- treated stratum corneum. Apparently, AcHA could enhance the intrinsic water holding capacity of stratum corneum. These findings indicate that the exce llent skin-softening effect of AcHA is due to the enhancement of the bound water content in the stratum corneum. (C) 2000 Elsevier Science Ltd. All ri ghts reserved.