Development of cosmetic moisturizer formulations and evaluation of hydrating efficacy by biophysical methods / Desenvolvimento de formulações cosméticas hidratantes e avaliação da eficácia por métodos biofísicos

AUTOR(ES)
DATA DE PUBLICAÇÃO

2009

RESUMO

Introduction: Hydration of the corneal layer varies according to the amount of water present; the transportation of water from the lower layers; evaporation speed and quantity and composition of epicutaneous emulsion. Proof of moisturizer formula efficiency must be prudent and analyzed using appropriate methods. Objective: The studys main objective was to assess the in vivo efficacy of moisturizer formulas with different active components by means of electrical capacitance and transepidermal water loss. The accelerated stability of the referred to formulas was also observed and assessed. Performances between Corneometer® and Moisturemeter® and between Vapometer® and Tewlmeter® were compared. In vitro behavior of alterations caused by moisturizing substances was verified in an alternative corneal stratum model. Material and Methods: The active compounds selected (4% p/p) for use in carbomer-based gels were: urea, Imperata cylindrica vegetal extract; a complex with natural moisturizing factors; sugar byproducts, saccharide isomerate and the mix of xylitol glucoside and anhydro xylitol glicoside. In vivo assessment of moisturizing efficacy of the formulas by means of electrical capacitance and transepidermal water loss was designed based in ANOVA three way factorial design. The gels were applied on both arms of volunteers aged 20 to 30 and a control application (base gel) and an untreated area were used. Study times were: after application and at 30, 60, 120; 240 and 360 minutes. The accelerated stability study of the formulations involved drastic storage conditions (temperature, humidity, luminosity) over 90 days. For the in vitro assessment of moisturizing substance behavior, Raman spectroscopy was used with Fourier Transform (FT-Raman) and differential scanning calorimetry (DSC). Results: Statistical analysis of electrical capacitance using Corneometer® and Moisturemeter® revealed significant differences between the gels and application time. With regard to transepidermal water loss measures, the results obtained from Vapometer® and Tewlmeter® did not reveal concordance. The bands found in the FT-Raman spectrum revealed that the active moisturizers did not cause changes in the alternative cornea stratum conformation structure. Calorimetry (DSC) analysis showed the urea gel increased membrane water content. Conclusion: Gels containing 4% (p/p) urea and 4% (p/p) of sugar byproduct had the best in vivo moisturizing efficacy, electrical capacitance when analyzed with Corneometer® and Moisturemeter®. In relation to transepidermal water loss, the base gel without active ingredients had the best result in both Vapometer® and Tewlmeter®. The formulas were stable for a period of three months in the studied storage conditions. In relation to capacitance measures, Corneometer® and Moisturemeter® proved to be statistically similar. When comparing transepidermal water loss measures, statistical analysis indicated that Vapometer® is not as precise as Tewlmeter®. In vitro assessment of behavior of moisturizing substances suggested they are safe.

ASSUNTO(S)

perda de água transepidérmica tewlmeter® vapometer® cosmetics moisturemeter® tewlmeter® corneometer® electrical capacitance hidratação vapometer® capacitância elétrica transepidermal water loss corneometer® moisturemeter® moisturizing

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