Ocular Drug Delivery

A special issue of Pharmaceutics (ISSN 1999-4923).

Deadline for manuscript submissions: closed (30 December 2011) | Viewed by 46759

Special Issue Editor

Director of Clinical Research, Eugene and Marilyn Glick Eye Institute, Indiana University School of Medicine, 702 Rotary Circle, Room 137, Indianapolis, IN 46202, USA
Interests: glaucoma; diabetes; age-related macular degeneration; vascular; blood flow; ischemia; perfusion; treatments
Special Issues, Collections and Topics in MDPI journals

Keywords

  • glaucoma
  • diabetes
  • age-related macular degeneration
  • vascular
  • blood flow
  • ischemia
  • perfusion
  • treatments

Published Papers (5 papers)

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Research

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3246 KiB  
Article
Evaluation of Tissue Interactions with Mechanical Elements of a Transscleral Drug Delivery Device
by Sarah J. Cohen, Robison V. Paul Chan, Mark Keegan, Christopher M. Andreoli, Jeffrey T. Borenstein, Joan W. Miller and Evangelos S. Gragoudas
Pharmaceutics 2012, 4(1), 212-229; https://doi.org/10.3390/pharmaceutics4010212 - 12 Mar 2012
Cited by 2 | Viewed by 7098
Abstract
The goal of this work was to evaluate tissue-device interactions due to implantation of a mechanically operated drug delivery system onto the posterior sclera. Two test devices were designed and fabricated to model elements of the drug delivery device—one containing a free-spinning ball [...] Read more.
The goal of this work was to evaluate tissue-device interactions due to implantation of a mechanically operated drug delivery system onto the posterior sclera. Two test devices were designed and fabricated to model elements of the drug delivery device—one containing a free-spinning ball bearing and the other encasing two articulating gears. Openings in the base of test devices modeled ports for drug passage from device to sclera. Porous poly(tetrafluoroethylene) (PTFE) membranes were attached to half of the gear devices to minimize tissue ingrowth through these ports. Test devices were sutured onto rabbit eyes for 10 weeks. Tissue-device interactions were evaluated histologically and mechanically after removal to determine effects on device function and changes in surrounding tissue. Test devices were generally well-tolerated during residence in the animal. All devices encouraged fibrous tissue formation between the sclera and the device, fibrous tissue encapsulation and invasion around the device, and inflammation of the conjunctiva. Gear devices encouraged significantly greater inflammation in all cases and a larger rate of tissue ingrowth. PTFE membranes prevented tissue invasion through the covered drug ports, though tissue migrated in through other smaller openings. The torque required to turn the mechanical elements increased over 1000 times for gear devices, but only on the order of 100 times for membrane-covered gear devices and less than 100 times for ball bearing devices. Maintaining a lower device profile, minimizing microscale motion on the eye surface and covering drug ports with a porous membrane may minimize inflammation, decreasing the risk of damage to surrounding tissues and minimizing disruption of device operation. Full article
(This article belongs to the Special Issue Ocular Drug Delivery)
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Review

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96 KiB  
Review
Ophthalmic Drug Delivery in Glaucoma—A Review
by Ingrida Januleviciene, Lina Siaudvytyte and Ruta Barsauskaite
Pharmaceutics 2012, 4(1), 243-251; https://doi.org/10.3390/pharmaceutics4010243 - 21 Mar 2012
Cited by 27 | Viewed by 6778
Abstract
Glaucoma is a progressive optic neuropathy and medical therapy is the initial option for the treatment of this potentially blinding condition. Topical instillation of eye drops from the bottle is the most common glaucoma drug delivery form. Due to limited permeability of anterior [...] Read more.
Glaucoma is a progressive optic neuropathy and medical therapy is the initial option for the treatment of this potentially blinding condition. Topical instillation of eye drops from the bottle is the most common glaucoma drug delivery form. Due to limited permeability of anterior ocular surface, natural clearance and drainage, eye drops contain large amounts of inactive ingredients. Effective penetration enhancers are known as irritants causing ocular discomfort. Although drug efficacy is determined by active ingredients, inactive agents can affect tolerance and can result in conjunctival irritation and hyperemia and influence patients’ adherence and quality of life. Full article
(This article belongs to the Special Issue Ocular Drug Delivery)
227 KiB  
Review
Delivery of Intraocular Triamcinolone Acetonide in the Treatment of Macular Edema
by Aaron Pickrell, Alon Harris, Sandra Ngo, Annahita Amireskandari, Erin Stewart and Brent Siesky
Pharmaceutics 2012, 4(1), 230-242; https://doi.org/10.3390/pharmaceutics4010230 - 15 Mar 2012
Cited by 5 | Viewed by 9868
Abstract
Macular edema (ME) is one of the eventual outcomes of various intraocular and systemic pathologies. The pathogenesis for ME is not yet entirely understood; however, some of the common risk factors for its development have been identified. While this investigation will not discuss [...] Read more.
Macular edema (ME) is one of the eventual outcomes of various intraocular and systemic pathologies. The pathogenesis for ME is not yet entirely understood; however, some of the common risk factors for its development have been identified. While this investigation will not discuss the numerous etiologies of ME in detail, it appraises the two most widely studied delivery modalities of intraocular corticosteroids in the treatment of ME—intravitreal injection (IVI) and sub-Tenon’s infusion (STI). A thorough review of the medical literature was conducted to identify the efficacy and safety of IVI and STI, specifically for the administration of triamcinolone acetonide (TA), in the setting of ME in an attempt to elucidate a preferred steroid delivery modality for treatment of ME. Full article
(This article belongs to the Special Issue Ocular Drug Delivery)
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175 KiB  
Review
Ocular Drug Delivery for Glaucoma Management
by Nathan Gooch, Sarah A. Molokhia, Russell Condie, Randon Michael Burr, Bonnie Archer, Balamurali K. Ambati and Barbara Wirostko
Pharmaceutics 2012, 4(1), 197-211; https://doi.org/10.3390/pharmaceutics4010197 - 08 Mar 2012
Cited by 53 | Viewed by 9566
Abstract
Current glaucoma management modalities are hindered by low patient compliance and adherence. This can be due to highly complex treatment strategies or poor patient understanding. Treatments focus on the management or reduction of intraocular pressure. This is most commonly done through the use [...] Read more.
Current glaucoma management modalities are hindered by low patient compliance and adherence. This can be due to highly complex treatment strategies or poor patient understanding. Treatments focus on the management or reduction of intraocular pressure. This is most commonly done through the use of daily topical eye drops. Unfortunately, despite effective therapies, glaucoma continues to progress, possibly due to patients not adhering to their treatments. In order to mitigate these patient compliance issues, many sustained release treatments are being researched and are entering the clinic. Conjunctival, subconjunctival, and intravitreal inserts, punctal plugs, and drug depots are currently in clinical development. Each delivery system has hurdles, yet shows promise and could potentially mitigate the current problems associated with poor patient compliance. Full article
(This article belongs to the Special Issue Ocular Drug Delivery)

Other

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687 KiB  
Other
Breakdown of the Blood-Ocular Barrier as a Strategy for the Systemic Use of Nanosystems
by Marcelo L. Occhiutto, Fatima R. Freitas, Raul C. Maranhao and Vital P. Costa
Pharmaceutics 2012, 4(2), 252-275; https://doi.org/10.3390/pharmaceutics4020252 - 14 May 2012
Cited by 63 | Viewed by 12882
Abstract
Several drug delivery systems have been proposed to overcome physiological barriers, improving ocular bioavailability. Systemic routes are seldom used due to the blood-ocular barrier. Novel drug delivery systems based on nanotechnology techniques have been developed to overcome ocular physiological barriers. This non-systematic review [...] Read more.
Several drug delivery systems have been proposed to overcome physiological barriers, improving ocular bioavailability. Systemic routes are seldom used due to the blood-ocular barrier. Novel drug delivery systems based on nanotechnology techniques have been developed to overcome ocular physiological barriers. This non-systematic review suggests the utilization of a transitory blood-ocular breakdown to allow the access of drugs by nanotechnology drug delivery systems via the systemic route. We discuss the possible ways to cause the breakdown of the blood-ocular barrier: acute inflammation caused by intraocular surgery, induced ocular hypotony, and the use of inflammatory mediators. The suitability of use of the systemic route and its toxic effects are also discussed in this article. Full article
(This article belongs to the Special Issue Ocular Drug Delivery)
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