Development and Characterization of Levofloxacin-Loaded Vitamin A-Poly(Ethylene Brassylate-Co-Squaric Acid)...

Currently, increased interest has been attributed to oil-in-water nanoemulsions, as their remarkable intrinsic properties fulfill the requirements to be employed as ophthalmic drug delivery systems. In this regard, the main purpose of the present study is to develop nanoemulsions consisting of vitamin A, poly(ethylene brassylate-co-squaric acid) (PEBSA), and levofloxacin as a potential ophthalmic drug delivery system with dual therapeutic effect. Two PEBSA variants with different ratios between comonomers are synthesized via ethylene brassylate macrolactone ring-opening and copolymerization with squaric acid using the emulsion technique and subsequently characterized. Furthermore, six nanoemulsions consisting of vitamin A and PEBSA are prepared. The effect of the dispersed phase concentration and the chemical composition of the copolymer on their dimensional distribution is appraised through laser diffraction analysis. All nanoemulsions has nanometric sizes, the optimal variants exhibiting an average diameter of 159 and 134 nm, respectively. The optimal formulations are loaded in situ with levofloxacin, a bioactive principle prescribed for ocular bacterial diseases. In vitro drug release results disclosed that levofloxacin is released in a controlled manner, reaching 84%, respectively 98%, after 24 h, depending on the copolymer squaric acid content. At the same time, nanoemulsions demonstrated good antimicrobial activity against the tested bacterial strains and are cytocompatible with the MG-63 cell line.