Desenvolvimento de um hidrogel de base nanotecnológica contendo um composto da classe benzofuroazepinos com potencial fotoprotetor in vitro

Abstract

The excessive exposure to a range of sunlight corresponding to UVB range (ʎ = 280-320 nm) and UVA (ʎ = 320-400 nm) is the main cause of human skin damage. These changes are attributed to damage to biomolecules such as lipids, proteins and DNA. To date, the use of sunscreens is considered the most effective approach to avoid and attenuate the harmful effects of UV radiation on skin. However, the sunscreen formulations have limitations regarding their photostability, effectiveness and safety by users. In this context, benzofuranoazepine class has chemical characteristics with potential for the absorption of UV radiation. In addition, the application of nanotechnology in sunscreens is promising because it is able in modulate the limitations of formulations. Therefore, the aim of this study was to screen benzofuroazepine compound with a broad-spectrum absorption profile in the UVB and UVA ranges. Aiming at selecting the molecule with the highest photoprotective potential the UV absorption spectrum profile of three compounds (10μg/mL) was assessed. Polymeric nanocapsules containing the selected compound (3mg/mL) were developed and characterized in terms of size, polydispersity index, pH, zeta potential and compound content. In addition, the toxicity of the free or nanoencapsulated compound forms and the influence of nanoencapsulation in UV light absorptive/scatter properties of compound were evaluated. In a subsequent step the hydrogels containing nanocapsule suspensions were proposed using gellan gum as a thickening agent. The in vitro photoprotective potential of the hydrogels was evaluated by the their ability to attenuate the generation of damages to the DNA molecule exposed to UVB and UVA light. The nanocapsule suspensions containing the selected compound had appropriate physicochemical characteristics (nanometric and homogeneous size distribution) and increased the UV light scattering in comparison to free compound. Hydrogels presented slightly acidic pH values, compound content of 3mg/g in the formulation, particle size in the nanometric range and spreadability profiles suitable to cutaneous application. All hydrogels containing the selected compound were effective against DNA damage induced by the UVB and UVA radiation. In conclusion, the present study showed the identification of a compound with potential for UV light absorption and the preparation of a nanotechnological-based hydrogel for cutaneous application.