Efficacy of dermocosmetic formulations containing dimethylaminoethanol (DMAE) and acetil hexapeptide-3

TF09

KASSANDRA A. TADINI, MIRELA D. GIANETI, PATRÍCIA M. B. G. MAIA CAMPOS

Departamento de Ciências Farmacêuticas, FCFRP/USP

Amongst the many active substances launched in the cosmetic market to treat and prevent skin ageing, dimetilaminoetanol (DMAE) and acetyl hexapeptide-3 should be emphasized, since these substances have been widely used in cosmetic formulations for that purpose. However, there are few studies in scientific literature that have conclusive data about the effectiveness and mechanism of action of these substances in the skin ageing. So, the aim of the present study was the clinical efficacy evaluation of dermocosmetic formulations containing DMAE or acetyl hexapeptide-3 by using Skin Biophysical Techniques. For this purpose, four formulations containing batyl alcohol and lecithin or C12-20 acid PEG-8 ester stabilized by different polymers (hydroxyethylcellulose or acrylate copolymer) were prepared. They were supplemented or not (vehicle) with 10% of a solution containing 0,05% acetyl hexapeptide-3 or 3% DMAE acetamidobenzoate and submitted to stability tests and sensorial analysis. For clinical efficacy studies, formulations were applied to the volar forearm and face of 40 female volunteers. Skin conditions in terms of skin moisture and skin mechanical properties (skin visco-elasticity and anisotropy) were evaluated by using Skin Biophysical Techniques (Corneometer^® CM 825, Cutometer^® SEM 575 and Reviscometer^® RV600, respectively) before and after a 14 and 28-day period of daily application. In the stability tests and sensorial analysis, it could be observed that the formulation containing C12-20 acid PEG-8 ester and acrylate copolymer was the most stable and showed the best sensorial attributes, and consequently was chosen as the vehicle for efficacy studies. The skin moisture evaluation showed that all formulations, containing or not the active substances under study provoked an enhancement in face skin water content of the stratum corneum. On the other hand, the formulations containing acetyl hexapeptide-3 altered skin anisotropy because they reduced the coefficient of variation (CV) of multidirectional RRTM (resonance running time measurements taken in 4 different directions 0º, 45º, 90º and 135º), which is a parameter inversely proportional to the speed of propagation of the emitted ultrasound wave at the skin surface and can suggest an increase of the skin firmness. The formulations under study did not provoke any significant alteration in skin visco-elasticity. Under the present experimental conditions it was possible to conclude that acetyl hexapeptíde-3 can be used in cosmetic formulations in order to enhance anti-ageing effects of cosmetic formulations, since this substance reduced CV values of multidirectional RRTM, improving skin anisotropy.