Development and Efficacy of a Drug-Releasing Soft Contact Lens

Abstract

PURPOSE. The purpose of this study was to investigate the uptake and the release of antibiotics from a newly synthesized drug delivery hydrogel soft contact lens (SCL) using an ion ligand mechanism.METHODS. The antibiotics used were Gatifloxacin (GFLX) and Moxifloxacin (MFLX). The uptake amount and the sustained-release kinetics of antibiotics were investigated in vitro, and were also compared with newly synthesized SCLs, etafilcon A and polymacon. The antibiotic concentrations in the cornea, aqueous humor, and crystalline lens, and the effect against bacterial proliferation were investigated in vivo using rabbit subjects. Additionally the drug release efficacy of the new SCL was compared with that of eye drop administrations.RESULTS. In vitro, antibiotic uptake was increased with the weight percent (wt%) of the anionic group, and the released amount of antibiotics was highest during the initial 1 hour period, which then decreased over the next 72 hours. The released antibiotics volume of the new SCLs was significantly higher throughout 72 hours than that of the other two materials, etafilcon A and polymacon (P < 0.01). Whereas in vivo, the concentrations found in the cornea and aqueous humor were higher than those for the eye drop groups (P < 0.05 or P < 0.01). Antibiotic release at those sites decreased over 72 hours. No bacterial populations were detectable in the group treated with the new SCL presoaked in antibiotics throughout the experimental periods. CONCLUSIONS.The new SCLs released the antibiotics over several days, and showed improved penetration into the eye, along with prevention of bacterial proliferation.

Simulation of the hydrodynamic conditions of the eye to better reproduce the drug release from hydrogel contact lenses: experiments and modeling

“…For example, instead of using a HEMA-based, which has a low oxygen permeability, we could use the newer silicon hydrogels that, due to their higher oxygen permeability would be more suitable for a prolonged drug release [13]. Also, the loading procedure could be modified to adjust the amount of drug released.…”

“…In certain situations, clinicians prescribe contact lenses to relief the ocular pain, promote the corneal healing, provide mechanical protection and support and maintain the corneal epithelial hydration [11]. They have also potential to be used as drug delivery devices [12,13], although till date there are no contact lenses loaded with drugs available in the market. So far, SCLs are only used in association with eyedrops, and in this case, they must be placed in the eye immediately after the application of the drops to increase the drugs residence time in the eye.…”

“…Several approaches are described in the literature, including the modification of the composition of the base materials by incorporation of monomers/compounds that enable to tailor the hydrogel properties [12,13], molecular imprinting with the drugs to create "cavities" in the polymeric matrix which affect the reloading/swelling of the hydrogels and the respective drug release [14] and grafting of ligands to the hydrogel matrix which form inclusion complexes with the drugs [15]. The possibility of creating two-layer contact lenses with an inner drugbearing biodegradable polymer film was also investigated [12].…”

Hydrogel Ring for Topical Drug Delivery to the Ocular Posterior Segment

“…16 The hydrophilic monomer HEMA (Mitsubishi Gas Chemical Company, Inc., Tokyo, Japan) and the crosslinkable monomer ethylene glycol dimethacrylate (EGDMA; Mitsubishi Rayon Co., Ltd., Tokyo, Japan) were mixed to concentrations of 99.5 wt% and 0.5 wt%, respectively. Polymerization was initiated using 2,2 0 -azobisisobutryronitrile (AIBN; Wako Pure Chemical Co., Ltd., Osaka, Japan) at a concentration of 0.1 wt%.…”

“…2-Hydroxyethyl methacrylate (HEMA), a nonbiodegradable material, is commonly used for ophthalmic applications, including contact lenses 15,16 and periocular inserts. 17 Therefore, HEMA was used as the main material to construct the ring examined in the current study.…”