A medical device/drug delivery system for treatment of glaucoma

Abstract

Background:The aim of this study was to investigate the uptake and release kinetics of two common glaucoma drugs delivered onto hydrogel contact lenses using analytical chemistry and to evaluate this device's ability to control intraocular pressure in a limited number of volunteers. Methods: Contact lenses were incubated in a source solution containing timolol maleate or brimonidine tartrate to determine uptake kinetics. The lenses were then immersed in fresh saline to determine release kinetics. Analysis was performed by high-pressure liquid chromatography (HPLC). HPLC column retention times were determined for drugs released from the lens individually and under co-elution conditions. To evaluate clinical feasibility and toxicity, three volunteers (patients being treated for glaucoma) were provided with contact lenses that had been passively impregnated with either drug. After a three-week wash-out period, the volunteers were instructed to wear the lenses for 30 minutes per day for two weeks. Results: HPLC analysis showed that maximum uptake and release of both drugs had occurred by approximately 60 minutes, with the slopes tending to flatten after this point. The retention time on the HPLC column was 8.08 minutes for timolol maleate and 2.16 minutes for brimonidine tartrate after incubation for one hour, with no changes after seven hours. Patient data showed that use of the lenses maintained IOP at levels equivalent to those obtained with previous treatment. No ocular toxicity was observed. Conclusion: Drugs commonly used for glaucoma treatment can be passively transferred to a hydrogel contact lens and then eluted from the polymer. Data obtained from a limited number of patients suggest that this contact lens/drug delivery system may be a feasible means of controlling IOP.

Dual drug delivery from vitamin E loaded contact lenses for glaucoma therapy

“…The control contact lens treatment decreased the IOP more significantly than eye drops by 0.88 ± 0.28 mmHg (p = 0.0294), despite the sixfold lower drug dosing compared to eye drops ( Table 1). The result was consistent with other in vivo [19,20,[46][47][48][49] and modeling studies [9] that showed the drug delivery by contact lens could provide a higher bioavailability. Similarly, the therapy from vitamin E modified contact lens lowered IOP during lens wear by comparable magnitude as eye drops but with 4-fold lower drug loading.…”

Biodegradable Implants for Sustained Drug Release in the Eye

“…Biodegradable PLA nanoparticles (140 nm) administered intravitreally have been shown to localize in the retinal pigment epithelium (51), and coating nanoparticles with polyethylene glycol (PEG) has been reported to enhance the therapeutic efficacy of treatment for ocular diseases such as autoimmune uveoretinitis (52). Drug-impregnated contact lenses have been widely investigated for the sustained release of ocular drugs (53)(54)(55). Soft contact lenses are typically composed of nonbiodegradable hydrogels of poly(2-hydroxyethylmethacrylate) (PHEMA) or hydroxyethylmethacrylate (HEMA) copolymerized with other monomers such as methacrylic acid, acetone acrylamide, and vinyl pyrrolidone.…”

Vitronectin: A Matrix Support Factor for Human Limbal Epithelial Progenitor Cells

“…2A). Given that previous studies have shown the delivery of biologicals and therapeutic agents to the ocular surface by CLs, 38,39 we sought to determine whether lenses could be coated with VN. Lotrafilcon A CLs were incubated in sera from patients with LSCD for 10 days before they were placed in PBS for an additional 7 days.…”