ABSTRACT
CONTEXT: Inclusion of antioxidants in topical formulations can contribute to minimize oxidative stress in the skin, which has been associated with photoaging, several dermatosis and cancer. OBJECTIVE: A Castanea sativa leaf extract with established antioxidant activity was incorporated into a semisolid surfactant-free formulation. The objective of this study was to perform a comprehensive characterization of this formulation. MATERIALS AND METHODS: Physical, microbiological and functional stability were evaluated during 6 months storage at 20 °C and 40 °C. Microstructure elucidation (cryo-SEM), in vitro release and in vivo moisturizing effect (Corneometer® CM 825) were also assessed. RESULTS AND DISCUSSION: Minor changes were observed in the textural and rheological properties of the formulation when stored at 20 °C for 6 months and the antioxidant activity of the plant extract remained constant throughout the storage period. Microbiological quality was confirmed at the end of the study. Under accelerated conditions, higher modifications of the evaluated parameters were observed. Cryo-SEM analysis revealed the presence of oil droplets dispersed into a gelified external phase. The release rate of the antioxidant compounds (610 ± 70 µgh(-0.5)) followed Higuchi model. A significant in vivo moisturizing effect was demonstrated, that lasted at least 4 h after product's application. CONCLUSION: The physical, functional and microbiological stability of the antioxidant formulation was established. Specific storage conditions should be recommended considering the influence of temperature on the stability. A skin hydration effect and good skin tolerance were also found which suggests that this preparation can be useful in the prevention or treatment of oxidative stress-mediated dysfunctions.
Subject(s)
Antioxidants/chemistry , Chemistry, Pharmaceutical/methods , Fagaceae , Plant Extracts/chemistry , Plant Leaves , Surface-Active Agents , Administration, Cutaneous , Adult , Antioxidants/administration & dosage , Antioxidants/isolation & purification , Female , Humans , Male , Middle Aged , Plant Extracts/administration & dosage , Plant Extracts/isolation & purification , Skin Absorption/drug effects , Skin Absorption/physiology , Young AdultABSTRACT
The predictors of terrorism are unclear. This paper examines the effect of public opinion in one country toward another country on the number of terrorist attacks perpetrated by people or groups from the former country against targets in the latter country. Public opinion was measured by the percentage of people in Middle Eastern and North African countries who disapprove of the leadership of nine world powers. Count models for 143 pairs of countries were used to estimate the effect of public opinion on terrorist incidents, controlling for other relevant variables and origin-country fixed effects. We found a greater incidence of international terrorism when people of one country disapprove of the leadership of another country.
