Contact lenses: promising devices for ocular drug delivery

In the ocular pharmacology market, there is a noteworthy unmet demand for more efficacious delivery of ocular therapeutics. Contact lenses are emerging as an alternative ophthalmic drug delivery system to resolve the drawbacks of the conventional topical application methods. Thus, contact lenses drug delivery systems have been developed to provide an increased residence time of the drug at the surface of the eye leading to enhanced bioavailability and more convenient and efficacious therapy. Several research groups have already explored the feasibility and potential of contact lenses loading conventional drugs used to treat anterior eye disorders. Drug incorporation to the lens body is achieved with techniques, like simple soaking, inclusion of drug-loaded colloidal nanoparticles, or molecular imprinting. Regardless of the technique used, key properties of the contact lens, such as transparency and oxygen permeability, should be preserved. In this article, we reviewed the different techniques used for drug delivery through contact lenses, analyzing their advantages and disadvantages, and focused on articles describing contact lens-based ophthalmic drug delivery systems with significant potential to use in ocular therapeutics.