科研之友
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摘要
Although various compounds from Ilex paraguariensis present high antioxidant activity, limitations in terms of chemical stability may be found, impacting on the formulation step. In this context, nanotechnology may be alternatively used to provide an additional protection for these compounds, avoiding degradative reactions. Different formulation parameters (eg. particle size, zeta potential, internal phase fraction) were assayed to maximize a local antioxidant action. Firstly, the extraction procedure for obtaining increased concentrations of antioxidant compounds was optimized. High stirring speed and ethanol as extractor liquid were defined as key parameters. Nanoparticles were prepared by double emulsion solvent evaporation technique. Polycaprolactone-based nanoparticles showed to be more stable than poly(lactic-co-glycolic acid)-based nanoparticles. Instead of poly(vinyl alcohol), Pluronic was selected as surfactant because it avoids aggregate formation and provides smaller particle size. While higher polymer content contributes positively to maintaining both reduced size particle and distribution, an increased extract concentration impacted negatively on these parameters. Stability studies were also performed using skin extracts and homogenates and confirmed that nanostructures provide an additional protection. Moreover, the incorporation of Ilex extract in nanoparticles significantly reduced the amount of chlorogenic acid permeated through the skin (no ex vivo permeation until 12 h for this system), extending its topical antioxidant effect.
- 出版日期2017-12-1
