POLYMER-BASED THIN FILMS FOR PSORIASIS TREATMENT: INSIGHTS INTO FORMULATION DESIGN

Psoriasis is a complex dermatological condition marked by red, scaly plaques, with its pathogenesis significantly driven by oxidative stress and free radical-induced cellular damage. Gallic acid (GA), a potent polyphenolic antioxidant, has the potential to counteract the oxidative stress associated to inflammation. This study investigates the development of polymeric thin films formulations for skin application, aimed psoriasis treatment. Hydrogels were formulated with 10% Polyvinyl Alcohol (PVA) and 2% Xanthan Gum, incorporating Gallic Acid (GA) at of 3 mg/mL and 30 mg/mL. Polymeric blends were prepared with PVA to XA ratios of 9:1, 8:2, and 7:3 (v/v), and thin films produced by using blade coating technique. Morphological characterization was performed by Scanning Electron Microscopy (SEM), while thickness was measured using ImageJ software. Physicochemical analyses included Fourier-transform infrared spectroscopy (FTIR) for chemical interactions, UV-Vis spectroscopy for GA quantification, and rheological evaluations involving flow curves measurements and synergy. In vitro cell viability was assessed in keratinocytes (HaCat cell line). SEM analysis revealed smooth surfaces on the films with rougher textures on the reverse side due to the coating process. The average film thicknesses were 48.91 ± 4.13 μm (9:1), 50.56 ± 7.45 μm (8:2), and 61.76 ± 7.89 μm (7:3). FTIR spectra showed similar patterns, aligning closely with control bands for each component. Films with 30 mg/ml GA demonstrated significant variation, with the 9:1 formulation differing notably from the 7:3 formulation (p < 0.05). Rheological analysis indicated that increasing XA concentration improved the material interactions and mechanical resistance, with the 7:3 formulation exhibiting approximately 2-fold synergy of the 8:2 and 10-fold that for 9:1 formulation. Cell viability tests showed that PVA did not significantly impact cell viability. In contrast, GA at 80 μg/ml significantly decreased cell viability compared to lower concentrations (p ≤ 0.001). XA concentrations of 1000 μg/ml and 2000 μg/ml also exhibited statistically significant differences in cell viability (p ≤ 0.05). XA in formulations improved film stability and mechanical properties. Optimizing XA levels may lead to more effective and stable films adequate to skin surface.