Development and enhanced stability of an oleuropein-loaded topical formulation for modified delivery and potential use for wound and burn therapy.

Abstract

This study aimed to develop and evaluate semi-solid topical formulations containing oleuropein, a phenolic compound with strong antioxidant and anti-inflammatory activity, for wound and burn treatment. The primary hypothesis was that optimizing formulation type would improve oleuropein stability, release behavior, and dermal compatibility, thereby enhancing therapeutic performance. Oleuropein isolated from olive leaves was incorporated into ointment (F1), cream (F2), and gel (F3) formulations at 1%, 2.5%, and 5%. Physicochemical characterization included pH, rheology, drug content, and in vitro release. UV-Vis spectrophotometric analysis at 280 nm was optimized to prevent excipient interference and ensure selective quantification in semi-solid matrices. Drug release was evaluated using the dialysis bag method, and stability was assessed under short-, long-term, and accelerated conditions by monitoring active content and viscosity. Among all formulations, the cream F2.1 showed the most favorable profile, with a physiologically compatible pH (∼5.4) and high initial viscosity (64 Pa·s at 5 rpm, TF-96 spindle), exhibiting shear-dependent reduction consistent with non-Newtonian pseudoplastic flow suitable for dermal application. F2.1 achieved 13.5% cumulative release over 7 h, indicating modified delivery. Stability studies demonstrated acceptable active retention under standard conditions, while partial degradation occurred under accelerated storage. Overall, F2.1 provided improved stability and modified topical delivery, supporting further biological and in vivo evaluation.