Development and Evaluation of an Anti-Inflammatory Emulsion: Skin Penetration, Physicochemical Properties, and Fibroblast Viability Assessment.

Background/Objectives. Chronic inflammatory skin disorders, such as atopic dermatitis and psoriasis, require safe and effective topical treatments. This study aimed to develop and evaluate a novel anti-inflammatory emulsion enriched with menthol, capsaicin, amino acids (glycine, arginine, histidine), and boswellic acid. Methods. Three formulations were prepared: a control (E1), a partial (E2), and a comprehensive formulation (E3). Physicochemical analyses included texture profiling, rheological behavior, pH stability, moisture content, and particle size distribution. Results. E3 demonstrated superior colloidal stability, optimal pH (5.75-6.25), and homogenous droplet size (<1 µm), indicating favorable dermal delivery potential. Ex vivo permeation studies revealed effective skin penetration of menthol and amino acids, with boswellic acid remaining primarily in the epidermis, suggesting localized action. Under oxidative stress conditions, E3 significantly improved fibroblast viability, indicating synergistic cytoprotective effects of combined active ingredients. While individual compounds showed limited or dose-dependent efficacy, their combination restored cell viability to near-control levels. Conclusions. These findings support the potential of this multi-component emulsion as a promising candidate for the topical management of inflammatory skin conditions.