Melatonin loaded nanostructured lipid carriers for the treatment of uveal melanoma

Uveal melanoma, a highly aggressive intraocular tumor and the second most common form of ocular malignancy, currently lacks effective therapeutic options. Therefore, this study addresses an unmet medical need by developing nanostructured lipid carriers (NLC) as a potential delivery system for melatonin (MEL) to target uveal melanoma. NLC were optimized for ophthalmic administration by the addition of a cationic surfactant to increase mucoadhesivity to the negatively charged ocular surface. MEL-loaded NLC (MEL-NLC) exhibited suitable particle size (<200 nm), good colloidal stability (5 months), and sustained MEL release. In vitro cytotoxicity assays demonstrated antiproliferative activity against uveal melanoma cells while maintaining corneal cell viability, further confirmed by in vitro HET-CAM test and in vivo ocular tolerance studies. Additionally, inflammation studies were performed since inflammation constitutes one of the main hallmarks of cancer development and progression. Consequently, MEL-NLC displayed anti-inflammatory properties. Furthermore, preliminary biodistribution results suggested their ability to reach the posterior segment of the eye, mainly the retina and the ciliary body, positioning them as a promising strategy for uveal melanoma treatment.