Chitosan coated sodium alginate–chitosan nanoparticles loaded with 5-FU for ocular delivery: In vitro characterization and in vivo study in rabbit eye

The objective of the study was to develop chitosan (CH) coated sodium alginate–chitosan (SA–CH) nanoparticles, i.e. CH-SA–CH NPs loaded with 5-FU for ophthalmic delivery. Drug loaded nanoparticles (DNPs) were prepared by ionic gelation technique using sodium alginate (SA) and chitosan (CH) and then suspended in chitosan solution. The mean size of nanoparticles and morphology were characterized by dynamic light scattering, scanning electron microscopy, atomic force microscopy and zeta potential. The in vitro release was studied by dialysis membrane technique. The size and drug encapsulation efficiency were dependent on molar ratio of SA and CH. The size of SA–CH nanoparticles was significantly increased with changed morphology after CH coating. SA–CH nanoparticles did not show any interaction with mucin while an enhanced viscosity was observed on coating of nanoparticles with CH. CH-SA–CH DNPs presented a sustained release of 5-FU compared to the 5-FU solution with high burst effect. In vivo study in rabbit eye showed significantly greater level of 5-FU in aqueous humor compared to 5-FU solution. The enhanced mucoadhesiveness of CH-SA–CH DNPs results in higher bioavailability as compared to the uncoated nanoparticles. Optimized formulation was found non-irritant and tolerable when tested by modified Draize test in rabbit eye.