Hydrogel based nanoparticulate ocular drug delivery systems

Poor ocular bioavailability of drugs (> 1%) from conventional eye drops (i.e. solution,suspension and ointments) is mainly due to the precorneal loss factor. Ocular efficacy is closely related to ocular drug bioavailability, which may be enhanced by increasing corneal drug penetration and prolonging precorneal drug residence time. Sparfloxacin and levofloxacin are newer generation hydrophobic fluoroquinolones. Poorly water soluble drugs are difficult to develop as conventional ocular drug delivery system. Nanotechnology can be used to formulate poorly water soluble drugs as nanosuspension which can be further incorporated in to matrix of hydrogel. This combination thus offers the opportunity to address many of the formulation related issues with such drugs. A variety of ocular drug delivery systems, such as hydrogels, microparticles, nanoparticles, microemulsion, liposomes and collagen shields have been designed and investigated for improved ocular bioavailability. Amongst them, hydrogels and polymeric nanoparticles are the most interesting approaches to achieve local sustained delivery system. In the present work various hydrogel based systems are developed and evaluated.