Tear Film Lipid Layer (TFLL) is a multilayer lipid assembly covering the aqueous tear film at the cornea surface, and it is the first eye structure encountered by topical ophthalmic drugs. TFLL contains polar and nonpolar lipids, forming a complex and dynamic interface. Several strategie to improve ophthalmic drug penetration have been devised, in particular encapsulation in lipid carriers. Still, a molecular-level insight into the mechanisms of drug transport in tear film is mostly missing. This proposal aims at improving our understanding of penetration, accumulation and interactions of drug molecules with TFLL. We plan to employ Langmuir trough techniques coupled with fluorescence microscopy to study selected drug-model molecules, both bare and in lipid carriers, interacting with lipid mixtures mimicking TFLL. The experiments will be accompanied by advanced molecular dynamics simulations. By using such a combined approach, we will gain a detailed physicochemical understanding of drug-TFLL interactions, with potential importance for future development of drugs and drug carriers.