Development and Optimization of Sustained Release Moxifloxacin Hydrochloride Loaded Nanoemulsion for Ophthalmic Drug Delivery: A 3² Factorial Design Approach

Background: Moxifloxacin is a BCS class I drug used in the treatment of bacterial conjunctivitis and keratitis. Despite its high water solubility, it possesses limited bioavailability due to anatomical and physiological constraints associated with the eyes, which require multiple administrations to achieve a therapeutic effect. Objective: In order to prolong drug release and to improve antibacterial efficacy for the treatment of bacterial keratitis and conjunctivitis, moxifloxacin-loaded nanoemulsion was developed. Methods: The concentration of oil (oleic acid), a surfactant (tween 80), and a cosurfactant (propylene glycol) were optimized by employing a 3-level 2-factorial design of the experiment for the development of nanoemulsion. The developed nanoemulsion was characterized by particle size distribution, viscosity, refractive index, pH, drug content and release, Transmission Electron Microscopy (TEM), and antibacterial study. The compatibility of the drug with the excipients was accessed by Fourier Transform Infrared Spectroscopy (FTIR). Results: The average globule size was found to be 198.20 nm. The TEM study revealed that the globules were nearly spherical and well-distributed. In vitro drug release profile of the nanoemulsion showed a sustained drug release (60.12% at the end of 6 h) compared to drug solution, with complete drug released within 2 h. The antibacterial effectiveness of the drug-loaded nanoemulsion improved against S. aureus compared with the marketed formulation. Conclusion: The formulated sustained-release nanoemulsion could be a promising alternative to eye drops with improved patient compliance by minimizing dosing frequency with improved antibacterial activity.