Preparation and in vitro-in vivo evaluation of ofloxacin loaded ophthalmic nano structured lipid carriers modified with chitosan oligosaccharide lactate for the treatment of bacterial keratitis.

The objective of this study was to explore the potential of the nanostructured lipid carriers (NLCs) modified with chitosan oligosaccharide lactate (COL) for topical ocular application. Ofloxacin (OFX) loaded NLCs were prepared by microemulsion or high shear homogenization methods. For combination of NLCs Compritol HD5 ATO was used as solid lipid, oleic acid as liquid lipid, Tween 80 as surfactant, ethanol as co-surfactant. The optimum NLCs was modified with 0.75% COL. The properties of NLCs in the absence or presence of OFX (0.3%) were characterized as zeta potential, particle size, viscosity and pH, TEM, drug loading, encapsulation efficiency and anti-microbial properties. Ex-vivo penetration/permeation studies were performed with rabbit cornea in Franz-diffusion cells. The penetration rate of OFX from NM-COL4OFX and NH-COL4OFX were significantly higher than commercial solution. Based on the selected formulations, in vivo tests were carried out by eye-drop instillation of NLCs in rabbit. The addition of COL improved the preocular residence time, controlled the drug release and enhanced the corneal bioavailability. In conclusion, OFX COL modified NLCs prepared by high shear homogenization method could be offered as a promising strategy for ocular drug delivery.