A comprehensive review on contact lens for ophthalmic drug delivery

Recent Trends in Advanced Contact Lenses

“…Gas permeable rigid CLs were also manufactured from various materials such as cellulose acetate butyrate (CAB), pure silicone, silicone acrylate (siloxymetacrylate copolymer), and fluorocarbonate (fluoromethacrylate siloxy copolymer) . These materials exhibit a range of properties; for instance, CAB is softer than PMMA and more oxygen permeable . Siloxy methacrylate–based materials, on the other hand, exhibit wetting problem due to lipophilicity of the material which can lead to surface scratches and built‐up surface for deposits .…”

“…With the polymerization of HEMA in the presence of a cross‐linking agent like ethylene glycol dimethyacrylate (EDGMA), PHEMA lenses were synthesized. These CLs generally can uptake 38% water, and additional hydrophilic monomers can be introduced to increase the water uptake that will directly affect the oxygen permeability . Methacrylic acid (MA) is one of the candidates to increase the water content of the CL synthesized from HEMA.…”

“…Since their first development, there has been a great deal of interest in drug delivery through CLs . To this end, a range of techniques have been used to incorporate drugs into the CL matrix including molecular imprinting, soaking in a solution with the drug, polymeric particles, ion interactions, and microemulsion loading . During the synthesis of CL material, drugs can be incorporated via 1) soaking preformed CLs into concentrated drug solutions (drug soaking) and 2) manufacturing CLs along with the drug molecules.…”

Stimulus‐Responsive Hydrogel for Ophthalmic Drug Delivery

“…Compared to rigid contact lenses and non‐silicon hydrogel contact lenses, silicone‐based soft contact lenses exhibit a higher degree of oxygen permeability to overcome corneal edema. However, silicone hydrogel contact lenses are mainly composed of silicone‐based materials (PDMS, PTRIS) and hydrophilic components (PHEMA, PNVP), which prolong release duration and increase drug loading, respectively . Drug‐laden silicone‐based soft contact lens can greatly enhance the drug bioavailability through enhancing drug loading or prolonging the release duration …”

“…In 1965, the first drug‐laden hydrogel contact lens was developed by simply soaking the lens in a 1% homatropine aqueous solution, resulting in an enhanced treatment effect compared to eye drops alone . The soaking method, which is the simplest and most cost effective method of loading drugs into contact lenses, must be improved to further increase drug loading and prolong release duration.…”