Physicochemical Characterization and <i>In Vitro</i> Anti-Inflammatory Assessment of Novel Sodium Alginate Sponges Loading <i>Andiroba</i> Oil ( <i>Carapa guianensis</i> Aubl.) for Skin Dressings

This study describes the structural characterization of a novel formulation based on sodium alginate sponges loading the Amazonian <i>andiroba</i> oil (<i>Carapa guianensis</i> Aubl.) as a strategy for developing topical anti-inflammatory dressings. The characterization by X-ray diffraction revealed the amorphous profile of unloaded and <i>andiroba</i> oil-loaded sponges, indicating structural flexibility suitable for modifying the release profile of bioactives. Scanning electron microscopy revealed a porous, interconnected structure of the unloaded alginate sponges, whereas oil-loaded sponges exhibited smoother, thicker pore walls and localized densification, indicating the oil's influence on the polymeric matrix architecture. Fourier transform infrared spectra identified the ester, hydroxyl, and carboxylate groups, confirming the chemical signature of the <i>andiroba</i> oil and its interactions with the alginate matrix. Hirshfeld surface analysis of oleic acid, one of the main bioactive components of <i>andiroba</i> oil, revealed a predominance of hydrophobic contacts and hydrogen-bonding interactions, supporting its affinity for biological targets. Surface analysis also indicated high porosity (∼70% void volume), suggesting a potential application for topical delivery. Docking simulations showed favorable binding affinity of oleic acid to the active site of NF-kB (-5.75 kcal/mol) and iNOS (-5.15 kcal/mol), corroborating its anti-inflammatory potential. <i>In silico</i> pharmacokinetic profiling exhibited low skin permeation (Log <i>K</i> _p = -2.6 cm/s) of oleic acid, no blood-brain barrier penetration, and no interaction with P-glycoprotein. <i>Andiroba</i> oil-loaded sponges significantly reduced nitric oxide production in lipopolysaccharide-activated RAW 264.7 macrophages without affecting cell viability. The unloaded alginate sponges also showed mild nitric oxide inhibition at high concentration, confirming their inherent biocompatibility. Altogether, these findings support the use of the developed sponges as a promising bioactive dressing for the healing of inflamed wounds and other chronic skin conditions, combining Amazonian phytotherapy with innovative polymeric delivery systems.