Hydrogel Ring for Topical Drug Delivery to the Ocular Posterior Segment

Shikamura, Yuko; Yamazaki, Yoshiko; Matsunaga, Toru; Sato, Takao; Ohtori, Akira; Tojo, Kakuji

doi:10.3109/02713683.2015.1050738

Cited by 29 publications

(27 citation statements)

References 24 publications

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“…Although conventional eye drops or other surface-applied drug delivery formulations are rarely used to achieve posterior treatment, due to the physiological barriers that make bioavailability through this route challenging, Shikamura et al reported on scleral/corneal contact lenses and subconjunctival rings to deliver ofloxacin to the posterior segment of the eye (Shikamura et al, 2016). Their contact lens and ring hydrogels were made of PHEMA crosslinked with ethylene glycol dimethacrylate, polymerized with 2,2′azobisisobutyronitrile, and soaked in concentrated ofloxacin solution.…”

Section: Scls and Other Hydrogels For Topical Drug Deliverymentioning

confidence: 99%

Hydrogel-based ocular drug delivery systems: Emerging fabrication strategies, applications, and bench-to-bedside manufacturing considerations

Cooper

Yang

2019

Journal of Controlled Release

126

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The physiological barriers of the eye pose challenges to the delivery of the array of therapeutics for the effective medication of ocular diseases as well as patient compliance. While the innovations in drug encapsulation and release mechanisms, biocompatibility, and treatment duration have become highly sophisticated, the challenge of widespread application of hydrogel formulations in the clinic is still apparent. This article reviews the latest hydrogel formulations and their associated chemistries for use in ocular therapies, spanning from external anterior to internal posterior regions of the eye in order to evaluate the state of recent research. This article discusses the utility of hydrogels in soft contact lens, wound dressings, intraocular lens, vitreous substitutes, vitreous drug release hydrogels, and cell-based therapies for regeneration. Additional focus is placed on the pre-formulation, formulation, and manufacturing considerations of the hydrogels based on individual components (polymer chains, linkers, and therapeutics), final hydrogel product, and required preparations for clinical/commercial applications, respectively.

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Section: Scls and Other Hydrogels For Topical Drug Deliverymentioning

confidence: 99%

Hydrogel-based ocular drug delivery systems: Emerging fabrication strategies, applications, and bench-to-bedside manufacturing considerations

Cooper

Yang

2019

Journal of Controlled Release

126

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“…Small molecules with a hydroxyl group have high corneal permeability, favoring the corneal route [27]. The trajectory of the drug molecules starts with their passive diffusion via the corneal epithelium, through the stroma and endothelium into the anterior chamber, where the drug will carry out its pharmacological action [28] or will bind to melanin in the ciliary Fig. 1 Glaucoma therapeutic strategies and nanotechnology-based potential applications body and iris [29], or plasma proteins [30], which prolongs its half-life.…”

Section: Drug Delivery Routes Features and Limitations Of Current Gmentioning

confidence: 99%

Nanotechnology for Medical and Surgical Glaucoma Therapy—A Review

et al. 2019

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Glaucoma is the second leading cause of blindness worldwide. Even though significant advances have been made in its management, currently available antiglaucoma therapies suffer from considerable drawbacks. Typically, the success and efficacy of glaucoma medications are undermined by their limited bioavailability to target tissues and the inadequate adherence demonstrated by patients with glaucoma. The latter is due to a gradual decrease in tolerability of lifelong topical therapies and the significant burden to patients of prescribed stepwise antiglaucoma regimens with frequent dosing which impact quality of life. On the other hand, glaucoma surgery is restricted by the inability of antifibrotic agents to efficiently control the wound healing process without causing severe collateral damage and long-term complications. Evolution of the treatment paradigm for patients with glaucoma will ideally include prevention of retinal ganglion cell degeneration by the successful delivery of neurotrophic factors, anti-inflammatory drugs, and gene therapies. Nanotechnology-based treatments may surpass the limitations of currently available glaucoma therapies through optimized targeted drug delivery, increased bioavailability, and controlled release. This review addresses the recent advances in glaucoma treatment strategies employing nanotechnology, including medical and surgical management, neuroregeneration, and neuroprotection.

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“…Conjunctiva is a route for ocular drug absorption, particularly to the iris and ciliary body Patton, 1987, 1985;Shikamura et al, 2016), but most trans-conjunctival permeation leads to systemic drug absorption from the conjunctival sac (Urtti et al, 1994(Urtti et al, , 1985.…”

Section: Introductionmentioning

confidence: 99%

Corneal and conjunctival drug permeability: Systematic comparison and pharmacokinetic impact in the eye

Ramsay

Amo

Toropainen

et al. 2018

European Journal of Pharmaceutical Sciences

107

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On the surface of the eye, both the cornea and conjunctiva are restricting ocular absorption of topically applied drugs, but barrier contributions of these two membranes have not been systemically compared. Herein, we studied permeability of 32 small molecular drug compounds across an isolated porcine cornea and built a quantitative structure-property relationship (QSPR) model for the permeability. Corneal drug permeability (data obtained for 25 drug molecules) showed a 52-fold range in permeability (0.09-4.70 × 10 cm/s) and the most important molecular descriptors in predicting the permeability were hydrogen bond donor, polar surface area and halogen ratio. Corneal permeability values were compared to their conjunctival drug permeability values. Ocular drug bioavailability and systemic absorption via conjunctiva were predicted for this drug set with pharmacokinetic calculations. Drug bioavailability in the aqueous humour was simulated to be <5% and trans-conjunctival systemic absorption was 34-79% of the dose. Loss of drug across the conjunctiva to the blood circulation restricts significantly ocular drug bioavailability and, therefore, ocular absorption does not increase proportionally with the increasing corneal drug permeability.

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Hydrogel Ring for Topical Drug Delivery to the Ocular Posterior Segment

Cited by 29 publications

References 24 publications

Hydrogel-based ocular drug delivery systems: Emerging fabrication strategies, applications, and bench-to-bedside manufacturing considerations

Hydrogel-based ocular drug delivery systems: Emerging fabrication strategies, applications, and bench-to-bedside manufacturing considerations

Nanotechnology for Medical and Surgical Glaucoma Therapy—A Review

Corneal and conjunctival drug permeability: Systematic comparison and pharmacokinetic impact in the eye

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