Abstract
Purpose:
Moxifloxacin (Mox) eye drops to treat bacterial keratitis require more frequency of administration due to less corneal residence time and poor transcorneal penetration. In the present study developed and evaluated the Polylactic-co-glycolic Acid (PLGA)-chitosan Nanoplex system as a carrier for ocular delivery of Mox to improve ocular penetration and bioavailability by prolonging the ocular residence time.
Methods:
PLGA-chitosan Nanoplexes were prepared by formation of complex between PLGA and chitosan using 1-Ethyl-3-(3-dimethylaminopropyl) carbodiimide as chemical crosslinker. Double emulsification solvent evaporation method followed by homogenization of primary emulsion was used to produce Mox loaded PLGA-chitosan Nanoplexes. Nanoplexes were evaluated for drug content, particle size (PS), zeta potential (ZP) and invitro release. Male albino New Zealand rabbits were used as invivo model for the studies.
Results:
Formulation with 0.22% chitosan and pH 5.8 was optimized using response surface methodology and has PS of 120.3 nm, ZP of +29.99 mV, encapsulation efficiency of 63.4% and burst release of 25.7%. Interaction between PLGA and chitosan was confirmed by Fourier Transform Infrared and Nuclear Magnetic Resonance spectroscopy. The Near Infrared chemical imaging revealed Nanoplex was a matrix-type system. Transmission Electron Microscopy, Scanning Electron Microscopy and Atomic Force Microscopy images demonstrated nanoplexes were round and mono dispersed. Ability of Nanoplexes to retain over cornea was demonstrated by gamma scintigraphy. Ex vivo evaluation using developed OcuFlow apparatus show sustained release of Mox from the Nanoplex. Five-fold higher ocular bioavailability was observed for Mox nanoplexes compared to Mox solution. Histopathology studies show nanoplexes caused no epithelial damage. Pharmacodynamic studies to induce keratitis using Staphylococcus aureus in rabbit eyes show significantly less clinical scores with Mox Nanoplexes as compare to Mox solution treated eyes.
Conclusions:
Mox nanoplex is capable of significantly extending the corneal residence time and increase transcorneal penetration. Physico-chemical characteristics, together with in vitro and in vivo studies show PLGA-chitosan Nanoplexes were efficient carriers for delivery of Mox to treat bacterial keratitis with improved ocular bioavailability.
Keywords: 421 anterior segment •
573 keratitis •
607 nanotechnology