scholarly journals Ocular Drug Delivery to the Retina: Current Innovations and Future Perspectives

Pharmaceutics ◽  
2021 ◽  
Vol 13 (1) ◽  
pp. 108
Author(s):  
Hyeong Min Kim ◽  
Se Joon Woo
Keyword(s):  
Drug Delivery ◽  
Treatment Options ◽  
Drug Efficacy ◽  
Delivery Systems ◽  
Ocular Drug Delivery ◽  
Age Related Macular Degeneration ◽  
Future Perspectives ◽  
Age Related ◽  
Invasive Techniques

Treatment options for retinal diseases, such as neovascular age-related macular degeneration, diabetic retinopathy, and retinal vascular disorders, have markedly expanded following the development of anti-vascular endothelial growth factor intravitreal injection methods. However, because intravitreal treatment requires monthly or bimonthly repeat injections to achieve optimal efficacy, recent investigations have focused on extended drug delivery systems to lengthen the treatment intervals in the long term. Dose escalation and increasing molecular weight of drugs, intravitreal implants and nanoparticles, hydrogels, combined systems, and port delivery systems are presently under preclinical and clinical investigations. In addition, less invasive techniques rather than intravitreal administration routes, such as topical, subconjunctival, suprachoroidal, subretinal, and trans-scleral, have been evaluated to reduce the treatment burden. Despite the latest advancements in the field of ophthalmic pharmacology, enhancing drug efficacy with high ocular bioavailability while avoiding systemic and local adverse effects is quite challenging. Consequently, despite the performance of numerous in vitro studies, only a few techniques have translated to clinical trials. This review discusses the recent developments in ocular drug delivery to the retina, the pharmacokinetics of intravitreal drugs, efforts to extend drug efficacy in the intraocular space, minimally invasive techniques for drug delivery to the retina, and future perspectives in this field.

Advanced Hydrogels Based Drug Delivery Systems for Ophthalmic Delivery

2020 ◽  
Vol 13 (4) ◽  
pp. 291-300 ◽  
Author(s):  
Srividya Gorantla ◽  
Tejashree Waghule ◽  
Vamshi Krishna Rapalli ◽  
Prem Prakash Singh ◽  
Sunil Kumar Dubey ◽  
...  
Keyword(s):  
Drug Delivery ◽  
Drug Delivery Systems ◽  
Delivery Systems ◽  
Age Related Macular Degeneration ◽  
Stimuli Responsive ◽  
Duration Of Action ◽  
Age Related ◽  
Aqueous Gels ◽  
Ophthalmic Delivery ◽  
3D Printed

Hydrogels are aqueous gels composed of cross-linked networks of hydrophilic polymers. Stimuli-responsive based hydrogels have gained focus over the past 20 years for treating ophthalmic diseases. Different stimuli-responsive mechanisms are involved in forming polymer hydrogel networks, including change in temperature, pH, ions, and others including light, thrombin, pressure, antigen, and glucose-responsive. Incorporation of nanocarriers with these smart stimuli-responsive drug delivery systems that can extend the duration of action by increasing ocular bioavailability and reducing the dosing frequency. This review will focus on the hydrogel drug delivery systems highlighting the gelling mechanisms and emerging stimuli-responsive hydrogels from preformed gels, nanogels, and the role of advanced 3D printed hydrogels in vision-threatening diseases like age-related macular degeneration and retinitis pigmentosa. It also provides insight into the limitations of hydrogels along with the safety and biocompatibility of the hydrogel drug delivery systems.

An Implantable Device Design Concept for Ocular Drug Delivery

2012 ◽  
Author(s):  
Jae-Hwan Lee ◽  
Ramana M. Pidaparti
Keyword(s):  
Drug Delivery ◽  
Macular Degeneration ◽  
Ocular Drug Delivery ◽  
Eye Diseases ◽  
Age Related Macular Degeneration ◽  
Intravitreal Injections ◽  
Delivery Device ◽  
Drug Delivery Device ◽  
Age Related ◽  
Intraocular Hemorrhage

New drugs for curing eye diseases have been developing for a decade and are very unique for each eye diseases such as glaucoma, cataracts, and age-related macular degeneration (AMD). It is estimated that 1.6 million adults in the US over the age of 50 and above suffer from age-related macular degeneration and about 200,000 cases are diagnosed annually. Worldwide, about 500,000 cases are diagnosed annually [1]. Drugs currently utilized for AMD are delivered via repeated intravitreal injections of the drug into the eye. Risks of repeated intravitreal injections can include intraocular infections (endophthalmitis), intraocular hemorrhage, and retinal detachment. Also, reducing the frequency of dosing will clearly benefit the patient by reducing the need for risky intravitreal injections and improving the pharmacokinetics of the drug in the eye. The eye disease of posterior segment (Dry and Wet) has limits to deliver the drug to retina region using typical eye drop. The drug injection using a needle with syringe can deliver but it barely provide right amount of doses, or over doses that may cause more severe problem such as swelling, fatigue, and damaging photoreceptor molecules. Furthermore, most drugs run away in a month so that repeated injection is necessary. Developing an implantable drug delivery device will help reduce the costs and risks associated with frequent injections and facilitate delivering the drug in a controlled manner and in the required amounts, and improve therapeutic efficacy and safety of drugs. This study focuses on the design, simulation and development of the implantable ocular drug delivery device.

Chitosan Nanoparticles as New Ocular Drug Delivery Systems: In Vitro Stability, in Vivo Fate, and Cellular Toxicity

2005 ◽  
Vol 22 (6) ◽  
pp. 1007-1007 ◽  
Author(s):  
Angela M. de Campos ◽  
Yolanda Diebold ◽  
Edison L. S. Carbalho ◽  
Alejandro Sánchez ◽  
María José Alonso
Keyword(s):  
Drug Delivery ◽  
Drug Delivery Systems ◽  
Chitosan Nanoparticles ◽  
Delivery Systems ◽  
Ocular Drug Delivery ◽  
Cellular Toxicity ◽  
In Vitro Stability

scholarly journals Design of an Implantable Device for Ocular Drug Delivery

2012 ◽  
Vol 2012 ◽  
pp. 1-8 ◽  
Author(s):  
Jae-Hwan Lee ◽  
Ramana M. Pidaparti ◽  
Gary M. Atkinson ◽  
Ramana S. Moorthy
Keyword(s):  
Drug Delivery ◽  
Ocular Drug Delivery ◽  
Age Related Macular Degeneration ◽  
Ocular Diseases ◽  
Drug Management ◽  
Drug Delivery Device ◽  
Age Related ◽  
Diffusion Characteristics ◽  
Drug Reservoir ◽  
Silicon Based

Ocular diseases, such as, glaucoma, age-related macular degeneration (AMD), diabetic retinopathy, and retinitis pigmentosa require drug management in order to prevent blindness and affecting million of adults in USA and worldwide. There is an increasing need to develop devices for drug delivery to address ocular diseases. This study focuses on the design, simulation, and development of an implantable ocular drug delivery device consisting of micro-/nanochannels embedded between top and bottom covers with a drug reservoir made from polydimethylsiloxane (PDMS) which is silicon-based organic and biodegradable polymer. Several simulations were carried out with six different micro-channel configurations in order to see the feasibility for ocular drug delivery applications. Based on the results obtained, channel design of osmotic I and osmotic II satisfied the diffusion rates required for ocular drug delivery. Finally, a prototype illustrating the three components of the drug delivery design is presented. In the future, the device will be tested for its functionality and diffusion characteristics.

Chitosan Nanoparticles as New Ocular Drug Delivery Systems: in Vitro Stability, in Vivo Fate, and Cellular Toxicity

2004 ◽  
Vol 21 (5) ◽  
pp. 803-810 ◽  
Author(s):  
Angela M. de Campos ◽  
Yolanda Diebold ◽  
Edison L. S. Carvalho ◽  
Alejandro Sánchez ◽  
Maria José Alonso
Keyword(s):  
Drug Delivery ◽  
Drug Delivery Systems ◽  
Chitosan Nanoparticles ◽  
Delivery Systems ◽  
Ocular Drug Delivery ◽  
Cellular Toxicity ◽  
In Vitro Stability

scholarly journals Ocular Drug Delivery: A Special Focus on the Thermosensitive Approach

Nanomaterials ◽  
2019 ◽  
Vol 9 (6) ◽  
pp. 884 ◽  
Author(s):  
Simona Sapino ◽  
Daniela Chirio ◽  
Elena Peira ◽  
Elena Abellán Rubio ◽  
Valentina Brunella ◽  
...  
Keyword(s):  
Drug Delivery ◽  
Body Temperature ◽  
Drug Delivery Systems ◽  
Treatment Options ◽  
In Vitro Models ◽  
Delivery Systems ◽  
Special Focus ◽  
Drug Bioavailability

The bioavailability of ophthalmic therapeutics is reduced because of the presence of physiological barriers whose primary function is to hinder the entry of exogenous agents, therefore also decreasing the bioavailability of locally administered drugs. Consequently, repeated ocular administrations are required. Hence, the development of drug delivery systems that ensure suitable drug concentration for prolonged times in different ocular tissues is certainly of great importance. This objective can be partially achieved using thermosensitive drug delivery systems that, owing to their ability of changing their state in response to temperature variations, from room to body temperature, may increase drug bioavailability. In the case of topical instillation, in situ forming gels increase pre-corneal drug residence time as a consequence of their enhanced adhesion to the corneal surface. Otherwise, in the case of intraocular and periocular, i.e., subconjunctival, retrobulbar, peribulbar administration, among others, they have the undoubted advantage of being easily injectable and, owing to their sudden thickening at body temperature, have the ability to form an in situ drug reservoir. As a result, the frequency of administration can be reduced, also favoring the patient’s adhesion to therapy. In the main section of this review, we discuss some of the most common treatment options for ocular diseases, with a special focus on posterior segment treatments, and summarize the most recent improvement deriving from thermosensitive drug delivery strategies. Aside from this, an additional section describes the most widespread in vitro models employed to evaluate the functionality of novel ophthalmic drug delivery systems.

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