Alginate-chitosan film for ocular drug delivery: Effect of surface cross-linking on film properties and characterization

The characteristics of alginate-chitosan films intended for ocular drug delivery of gatifloxacin sesquihydrate were compared with the ionically surface cross-linked films of similar compositions. The effect of polymer ratios and cross-linking was studied relatively to various parameters of formulations including physicochemical, mechanical strength, swelling and bioadhesion. The drug release profiles and drug release mechanisms were compared. The folding endurance, tensile strength, bioadhesive strength considerably increased whereas swelling index, elongation at break decreased with surface cross-linking of the films. Surface cross-linked formulation F3 (2% w/v sodium alginate and 1% w/v chitosan) showed most prolonged drug release of 24h indicating the potential of surface cross linking of the film to sustain drug release. As per the kinetic models both type of films showed a constant drug release, however the drug release mechanism transformed from erosion to diffusion after cross linking. These results demonstrate that the surface treated alginate-chitosan film could be a potential vehicle to enhance ocular GS bioavailability and patient compliance.