Development of Photoprotective Formulations: Influence of Formulation Composition on the SPF and Mechanical Properties.

The evaluation of the vehicle formulation is important during the development of sunscreens, as it influences their efficacy. In this context, the aim of the present study was to develop photoprotective formulations and evaluate the influence of the formulation components in the sun protection factor (SPF) and physical-mechanical and sensory properties of the formulations. We evaluated four sunscreens through a 22 full factorial design in terms of concentration and emulsifier type. The design of experiments (DOE) parameters were SPF, thixotropy, and work of shear. After the screening of the formulations by DOE, the SPF values, mechanical and sensory properties, and stability were evaluated. All study formulations showed non-Newtonian pseudoplastic behavior, compatible with sunscreens, and presented SPF values above 30. The factors evaluated in DOE had significant interactions for all the analyzed parameters. The concentration of the phosphate-based emulsifier influenced the SPF parameter. The work of shear was influenced by the concentration of polyglyceryl-based emulsifier. The concentration and the type of emulsifier influenced the thixotropy. Finally, effective sunscreens were developed, and the type and concentration of emulsifiers had an influence on the SPF of the formulations. In addition, the formulations chosen by DOE were stable and showed good sensory properties.

Efficacy of topical antioxidants in the skin hyperpigmentation control: A clinical study by reflectance confocal microscopy.

BACKGROUND: Some in vitro studies have reported the potential of antioxidants for the reduction of melanogenesis. However, it is important to assess the clinical efficacy of these substances in reducing skin hyperpigmentation. Thus, the aim of this study was to evaluate the clinical efficacy of dermocosmetic formulations based on antioxidants using Reflectance confocal microscopy (RCM). METHODS: Thirty-two healthy females aged 39-55 years were enrolled and divided into four groups: Vehicle (V), V with ascorbyl tetraisopalmitate (ATIP), V with Spirulina sp., and V with hydroxytyrosol-titrated olive extract. Imaging analyses by high-resolution methods and RCM were performed in the malar region of the face before and after a 42-day period of application of the studied formulations. RESULTS: Reflectance confocal microscopy imaging analyses showed a significant reduction of number of hyperreflective pixels and basal layer brightness after 42 days of application of formulations containing the antioxidants compared to vehicle and baseline values, suggesting an improvement of the skin pigmentation pattern. CONCLUSION: Reflectance confocal microscopy permitted the identification of skin hyperpigmentation and the assessment of the clinical efficacy of dermocosmetic formulations based on antioxidants in a noninvasive way. All formulations containing antioxidants significantly reduced skin hyperpigmentation after the period of application.

Is Vitamin D3 Transdermal Formulation Feasible? An Ex Vivo Skin Retention and Permeation.

Vitamin D3 supplementation is important to prevent and treat hypovitaminosis that is a worldwide public health issue. Most types of supplementation are by oral route or fortification foods. The alternative route must be investigated, as transdermal route, for people with fat malabsorption or other diseases that impair the absorption of vitamin D3. This study focused on verifying the feasibleness of vitamin D3 skin retention and permeation with the presence of chemical penetration enhancers (soybean lecithin, isopropyl palmitate, propylene glycol, ethoxydiglycol, and cereal alcohol) at different pharmaceutical forms (gel and cream) through a human skin. The integrity of skin was evaluated by transepidermal water loss (TEWL) during the skin retention and permeation test. The combination of chemical penetration enhancers presented in cream did not compromise the skin, different from the gel that association of cereal alcohol and propylene glycol compromised the skin in 24 h. Gel formulation showed vitamin D3 detection at stratum corneum in 4 h and at epidermis and dermis in 24 h. Vitamin D3 demonstrated an affinity with the vehicle in the cream formulation and was detected at the skin surface. No active was found at receptor fluid for both formulations. In conclusion, the vitamin D3 did not indicate feasibleness for transdermal use probably due to its physical-chemical characteristics such as high lipophilicity since it was not permeated through a human skin. Nevertheless, the transdermal route should be continuously investigated with less lipophilic derivates of vitamin D3 and with different combination of penetration enhancers.