Therapeutic contact lenses for ophthalmic drug delivery: major challenges.

Eye drop solutions are widely used by the ophthalmologist to treat the anterior segment eye diseases. However, eye drop solutions have many limitations including low bioavailability, high dose requirements, and poor patient compliance. Contact lenses are used to deliver the ocular drugs with high ocular bioavailability due to its immediate location to cornea. To attend controlled and prolonged drug release from the contact lenses, scientists are working on various systems including polymeric nanoparticles, molecular imprinting, microemulsion, micelles, liposomes, implantation, supercritical fluids, and use of vitamin E. However, the changes in the critical lens properties like swelling, optical transparency, ion permeability, tensile strength, oxygen permeability, high burst release, issues during monomer extraction, sterilization and storage are yet to address. The review is focused on the commercial challenges with different methodologies to develop therapeutic contact lenses for commercial market. Many animal and clinical studies are under pipeline and it is likely that the therapeutic contact lenses will be commercialized in next few years.