Desenvolvimento e avaliação de eficácia de formulações fotoprotetoras para a pele oleosa contendo extrato de Anacardium occidentale

Abstract

MERCURIO, D. G. Development and efficacy evaluation of photoprotective formulations for oily skin containing extract of Anacardium occidentale. 2012. 148f. Dissertation (Master). Faculdade de Ciencias Farmaceuticas de Ribeirao Preto – Universidade de Sao Paulo, Ribeirao Preto, 2012. Oily skin has different characteristics and demands the use of cosmetic products that provide adequate and specific benefits to this skin type. In this context, the cashew extract (Anacardium occidentale), due to its rich composition, has properties that can provide benefits for oily skin care. The objective of this project was to develop stable photoprotective formulations containing glycolic extract of Anacardium occidentale, as well as to evaluate the clinical efficacy of these formulations for the improvement of oily skin conditions. For this purpose, the photoprotective formulations were developed with raw materials compatible with oily skin, which were submitted to preliminary tests of stability, and the most stable was selected to evaluate the sunscreen activity in vitro, sensory evaluation and assessment of clinical efficacy in terms of immediate (two and four hours after application) and long term effects (after 28 days of daily application of the formulations). It was also determined the spectrum of absorption of the cashew extract, antioxidant activity evaluation in vitro, and determination of polyphenols. Before de efficacy evaluation, studies were conducted to characterize and classify skin types using dermatological score and advanced biophysical techniques and skin imaging analysis. Among the formulations developed, the one which contained “Sodium Polyacrylate (and) Dimethicone (and) Cyclopentasiloxane (and) Trideceth-6 (and) PEG/PPG 18/18 Dimethicone e Acrylates/C10-30 Alkyl Acrylate Crosspolymer as emulsifiers and thickner agents and “Octyl Stearate” as an emollient and dispersing agent of the inorganic filter and Silica and 'Polymethyl Methacrylate as sensory modifiers powders (F15), this formulation was added of 3.5% of Glycolic extract of cashew (F15C) and was stable in preliminary tests of stability. In the evaluation of in vitro sunscreen activity, the formulation showed FPS 50, Boost Factor classified as Good and critical wavelength above 370 nm. Cashew glycolic extract showed dose-dependent antioxidant activity. The characterization of the skin demonstrated that the group with oily skin showed higher transepidermal water loss, greater asperity and oiliness. Furthermore, computer analysis of images showed differences in the sebum, pores and comedones in the regions of the cheeks, chin and nose. In the sensory evaluation studies, the formulation F15C showed better scores on parameters related with touch, oiliness, smoothness, residual brightness, and showed higher purchase intent. No immediate effects were obtained in stratum corneum water content, transepidermal water loss and the parameters of microrelief. The formulation F15C presented retention of the sebum content compared with the formulation vehicle after two and four hours of application of the formulation. In the long-term effects study, the formulation provided a reduction in the number of pores on the chin and did not increase the comedones and didn’t show significant changes in the parameters: stratum corneum water content, transepidermal water loss, parameters of the microrelief, sebum and counting active sebaceous glands. The formulation developed is presented as an innovative and efficient product with a pleasant sensory and compatible for use on oily skin. Furthermore, the cashew extract further improved the sensory properties of the formulation, showed antioxidant activity and clinical efficacy in the oil control and improvement of skin conditions.