title: Investigation of moxifloxacin loaded chitosan-dextran nanoparticles for topical instillation into eye: In-vitro and ex-vivo evaluation.
abstract: BACKGROUND
  Management of ocular surface disease by conventional formulation is limited by poor residence of drug at cul-de-sac of eye. To overcome this limitation, prolonged released mucoadhesive chitosan (CS)-dextran sulfate (DS) nanoparticles (NPs) were investigated for the prolonged topical ophthalmic delivery of moxifloxacin (Mox).
  
  
  METHODS
  Formulation was optimized by 3-factors (CS, DS, and Mox concentration), 3-levels (-1, 0, +1) Box-Behnken design. Optimized formulation was characterized for various in-vitro attributes, including particles size, zeta potential, shape and morphology, in-vitro release profile, corneal permeation, corneal retention, ocular tolerance test as well as antimicrobial activity.
  
  
  RESULTS
  Average hydrodynamic particle size of statistically optimized formulation was found to be 279.18 ± 15.63 nm with good polydispersity index, 0.367 ± 0.016 and positive zeta potential, +31.23 ± 1.32. NPs showed entrapment efficiency, 72.82 ± 3.6% and transmission electron microscopic analysis revealed a spherical shape of particles. Formulation exhibited biphasic release profile with an initial fast release (≈25% in 1(st) h) followed by sustained release (≈95% in next 24 h) following Korsmeyer-Peppas model with a nonFickian diffusion process. Mox loaded CS-DS NPs exhibited a significantly higher (P < 0.01), approximately 1.8-fold transcorneal permeation as well as significantly higher corneal retention (P < 0.01), around 4-5-fold when compared to free solution. Developed formulation exhibited safety profile comparable to normal saline, which was revealed by ocular tolerance test (Hen's egg test-chorioallantoic membrane). Mox-CS-DS NPs exhibited significantly high (P < 0.01) antimicrobial activity against Staphylococcus aureus and Pseudomonas aeruginosa.
  
  
  CONCLUSIONS
  In-vitro and ex-vivo studies revealed that developed formulation could be a potential substitute for prolonged topical ocular delivery.
authors.affiliation: Department of Pharmaceutics, College of Pharmacy, Hawler Medical University, Erbil, Iraq.
authors.forename: Raad A
authors.initials: RA
authors.lastname: Kaskoos
keywords: Chitosan; dextran; moxifloxacin; nanoparticles; ocular delivery; transcorneal permeation