Advances in drug-loaded contact lenses for glaucoma: Materials, evaluation parameters, and novel drug delivery strategies with modified nanoparticles

Glaucoma, a chronic eye disease characterized by high intraocular pressure, poses challenges in drug delivery due to ocular physiological barriers. Traditional formulations have limited residence time and are quickly drained away, leading to decreased efficacy and increased adverse drug reactions. Drug-laden contact lenses have garnered attention as a potential solution for sustained action of drug delivered to the eye. However, the development of such lenses presents challenges including lens swelling, transmittance, wearability, drug loading, and drug release. Incorporation of drug molecules into contact lens material can cause lens swelling and shape change, affecting lens fit and comfort. Drug loading and release are also critical factors. To overcome these challenges, researchers have explored strategies such as the use of nanoparticles. This review provides an overview of the materials used to prepare contact lenses, including silicone hydrogel, monomers like EGDMA, MAA, and NVP, and other additives like vitamin E and hyaluronic acid. The article comprehends and evaluates the key parameters for drug-loaded contact lenses, including transmittance, swelling index, oxygen permeability, drug loading, and drug release. The review also discusses drug loading with modified nanoparticles such as micelles, coated nanoparticles, and metallic nanoparticles. By selecting appropriate contact lens materials and optimizing key parameters, drug-laden contact lenses hold promise for improved care of glaucoma patients. Further research in this field can pave the way for more effective and convenient treatment options.