Joana Marto

The aim of the study was to prepare chloramphenicol (CAM)-loaded transfersomes to enhance drug permeability following topical administration, considering the final goal of treating conjunctivitis by applying the formulation onto the eyelid. The CAM-loaded transfersomes obtained have an average particle size of approximately 120 nm, are monodispersed with polydispersity index < 0.1, and exhibit high encapsulation efficiency (84 ± 5.5%). The formulation showed vesicle deformability, good biocompatibility and enhanced skin permeation compared to a conventional ophthalmic formulation of the antibiotic. The optimized drug-loaded nanosystem was subsequently jellified and the fluid gel obtained presented rheological behaviour adequate for application onto the eyelid. The formulation showed physical and chemical stability after 3 months storage. Therefore, eyelid administration of CAM-loaded transfersomes could be considered as a potential strategy for the treatment of bacterial conjunctivitis.

Background/Objectives: The consumption of olive oil and olives has been steadily increasing, leading to growing interest in the sustainable management of by-products such as olive stones. This work aimed to contribute to the development of valorization strategies by studying the chemical composition and biological potential of olive stone extracts, using both conventional and eco-friendly extraction methods with various solvents. Methods: Several extracts were prepared and chemically characterized regarding their fatty acid and phenolic profiles by GC-FID and HPLC-DAD-MS/MS, respectively. Their antioxidant, cytotoxic and antiproliferative activities were also evaluated. Results: n-Hexane Soxhlet extract yielded higher concentrations and a broader range of fatty acids when compared to the chloroform-methanol Folch extract. Oleic, palmitic, and linoleic acids were the predominant fatty acids in the extracts. A large variety of phenolic compounds were identified in extracts obtained by microwave-assisted extraction (MAE), including several flavonoids, small phenolic compounds, secoiridoids (nuezhenide and oleuropein), and hydroxytyrosol. MAE hydroalcoholic extracts showed high total phenolic content (TPC), antioxidant activity by the oxygen radical absorption capacity (ORAC) and hydroxyl radical scavenging capacity (HOSC) assays. Moreover, the aqueous ethanol (50%) and aqueous methanol (80%) extracts displayed low cytotoxicity toward the non-malignant Caco-2 cell line (IC₅₀ values of 1.29 and 1.40 mg/mL, respectively), while both induced complete loss of viability in the HT-29 human colon adenocarcinoma cell line at 0.63 mg/mL. Conclusions: These findings highlight the potential of olive stone as a valuable source of bioactive compounds with antioxidant and selective antiproliferative properties. The results support their further exploration in the development of sustainable valorization strategies for olive industry by-products.