Bioadhesive Eudragit RL^®100 Nanocapsules for Melanoma Therapy: A Repurposing Strategy for Propranolol

Background/Objectives: Cutaneous melanoma is a potent neoplasm whose advancement is linked to catecholamine-induced angiogenesis through β-adrenergic receptors. Propranolol (PROP), a non-selective β-blocker, holds potential in oncology, but its systemic side effects restrict its viability. This study aims to nanoencapsulate PROP in Eudragit RL^®100 polymeric nanocapsules for topical melanoma treatment. Methods: Nanocapsules were created through interfacial deposition of preformed polymer and characterized in terms of particle size, zeta potential, pH, drug content, and encapsulation efficiency. In vitro evaluations include release profile, antioxidant activity, bioadhesiveness, hemolysis, cytotoxicity, and antitumor effect on melanoma cells. Additionally, migration assays were conducted. Results: The nanocapsules displayed an acidic pH, an average size of 151 nm, and a positive zeta potential. An encapsulation efficiency of 81% was achieved, even with the hydrochloride form of the drug. The release profile exhibited sustained release of PROP, showcasing enhanced antioxidant activity in the nanoencapsulated form. The formulations also exhibited significant bioadhesion with mucin and an in vitro hemolysis rate over 50%, attributed to the cationic polymer and surfactants present. Moreover, in the cell viability assays, the NC-PROP formulations significantly reduced melanoma cell viability. In the migration assay, both the nanocapsules with and without the drug significantly inhibited cell migration, supporting the potential therapeutic benefits of these formulations. Conclusions: The nanoencapsulation of PROP in Eudragit RL^®100 presents a viable strategy for topical treatment of cutaneous melanoma, enhancing release duration and reducing systemic effects. The assessments indicated distinct physical properties and substantial therapeutic potential.