scholarly journals Drug Delivery to Anterior Segment of the Eye

2013 ◽  
pp. 42-67
Keyword(s):  
Drug Delivery ◽  
Anterior Segment

scholarly journals Nanotechnology for Topical Drug Delivery to the Anterior Segment of the Eye

2021 ◽  
Vol 22 (22) ◽  
pp. 12368
Author(s):  
Alexander Vaneev ◽  
Victoria Tikhomirova ◽  
Natalia Chesnokova ◽  
Ekaterina Popova ◽  
Olga Beznos ◽  
...  
Keyword(s):  
Drug Delivery ◽  
Anterior Segment ◽  
Drug Carriers ◽  
Ocular Tissue ◽  
Eye Drops ◽  
Topical Drug Delivery ◽  
Natural Polymers ◽  
Drug Bioavailability ◽  
Sustained Drug Release

Topical drug delivery is one of the most challenging aspects of eye therapy. Eye drops are the most prevalent drug form, especially for widely distributed anterior segment eye diseases (cataracts, glaucoma, dry eye syndrome, inflammatory diseases, etc.), because they are convenient and easy to apply by patients. However, conventional drug formulations are usually characterized by short retention time in the tear film, insufficient contact with epithelium, fast elimination, and difficulties in overcoming ocular tissue barriers. Not more than 5% of the total drug dose administered in eye drops reaches the interior ocular tissues. To overcome the ocular drug delivery barriers and improve drug bioavailability, various conventional and novel drug delivery systems have been developed. Among these, nanosize carriers are the most attractive. The review is focused on the different drug carriers, such as synthetic and natural polymers, as well as inorganic carriers, with special attention to nanoparticles and nanomicelles. Studies in vitro and in vivo have demonstrated that new formulations could help to improve the bioavailability of the drugs, provide sustained drug release, enhance and prolong their therapeutic action. Promising results were obtained with drug-loaded nanoparticles included in in situ gel.

A review of the clinical applications of drug delivery systems for the treatment of ocular anterior segment inflammation

2020 ◽  
pp. bjophthalmol-2020-315911
Author(s):  
Chee Wai Wong ◽  
Josbert M Metselaar ◽  
Gert Storm ◽  
Tina T Wong
Keyword(s):  
Drug Delivery ◽  
Clinical Trials ◽  
Patient Compliance ◽  
Anterior Segment ◽  
Topical Steroid ◽  
Medical Problem ◽  
Ocular Tissue ◽  
Cystoid Macular Oedema ◽  
Topical Steroids ◽  
Eye Drops

Ocular anterior segment inflammation is a medical problem that is seen in cases of cataract surgery and non-infectious anterior uveitis. Inadequately treated anterior segment inflammation can lead to sight-threatening conditions such as corneal oedema, glaucoma and cystoid macular oedema. The mainstay of treatment for anterior segment inflammation is topical steroid eye-drops. However, several drawbacks limit the critical value of this treatment, including low bioavailability, poor patient compliance, relatively difficult administration manner and risk of blurring of vision and ocular irritation. A drug delivery system (DDS) that can provide increased bioavailability and sustained delivery while being specifically targeted towards inflamed ocular tissue can potentially replace daily eye-drops as the gold standard for management of anterior segment inflammation. The various DDS for anti-inflammatory drugs for the treatment of anterior segment inflammation are listed and summarised in this review, with a focus on commercially available products and those in clinical trials. Dextenza, INVELTYS, Dexycu and Bromsite are examples of DDS that have enjoyed success in clinical trials leading to FDA approval. Nanoparticles and ocular iontophoresis form the next wave of DDS that have the potential to replace topical steroids eye-drops as the treatment of choice for anterior segment inflammation. With the current relentless pace of ophthalmic drug delivery research, the pursuit of a new standard of treatment that eliminates the problems of low bioavailability and patient compliance may soon be realised.

Phenylboronic-Acid-Based Polymeric Micelles for Mucoadhesive Anterior Segment Ocular Drug Delivery

2016 ◽  
Vol 17 (4) ◽  
pp. 1449-1457 ◽  
Author(s):  
Graeme Prosperi-Porta ◽  
Stephanie Kedzior ◽  
Benjamin Muirhead ◽  
Heather Sheardown
Keyword(s):  
Drug Delivery ◽  
Polymeric Micelles ◽  
Phenylboronic Acid ◽  
Anterior Segment ◽  
Ocular Drug Delivery

Optimization of Subconjunctival Biodegradable Microfilms for Sustained Drug Delivery to the Anterior Segment in a Small Animal Model

2013 ◽  
Vol 54 (4) ◽  
pp. 2607 ◽  
Author(s):  
Yu-Chi Liu ◽  
Yan Peng ◽  
Nyein Chan Lwin ◽  
Tina T. Wong ◽  
Subbu S. Venkatraman ◽  
...  
Keyword(s):  
Drug Delivery ◽  
Animal Model ◽  
Anterior Segment ◽  
Small Animal ◽  
Small Animal Model ◽  
Sustained Drug Delivery

scholarly journals Surface Engineering of FLT4-Targeted Nanocarriers Enhances Cell-Softening Glaucoma Therapy

2021 ◽  
Author(s):  
Michael P. Vincent ◽  
Trevor Stack ◽  
Amir Vahabikashi ◽  
Guorong Li ◽  
Kristin M. Perkumas ◽  
...  
Keyword(s):  
Drug Delivery ◽  
Endothelial Cells ◽  
Targeted Drug Delivery ◽  
Surface Engineering ◽  
Vision Loss ◽  
Open Angle Glaucoma ◽  
Anterior Segment ◽  
Schlemm’S Canal ◽  
Schlemm's Canal ◽  
Targeted Drug

Primary open-angle glaucoma is associated with elevated intraocular pressure (IOP) that damages the optic nerve and leads to gradual vision loss. Several agents that reduce the stiffness of pressure-regulating Schlemm's canal endothelial cells, in the conventional outflow pathway of the eye, lower IOP in glaucoma patients and are approved for clinical use. However, poor drug penetration and uncontrolled biodistribution limit their efficacy and produce local adverse effects. Compared to other ocular endothelia, FLT4/VEGFR3 is expressed at elevated levels by Schlemm's canal endothelial cells and can be exploited for targeted drug delivery. Here, we validate FLT4 receptors as a clinically-relevant target on Schlemm's canal cells from glaucomatous human donors and engineer polymeric self-assembled nanocarriers displaying lipid-anchored targeting ligands that optimally engage this receptor. Targeting constructs were synthesized as lipid-PEGX-peptide, differing in the number of PEG spacer units (x), and were embedded in micelles. We present a novel proteolysis assay for quantifying ligand accessibility that we employ to design and optimize our FLT4-targeting strategy for glaucoma nanotherapy. Peptide accessibility to proteases correlated with receptor-mediated targeting enhancements. Increasing the accessibility of FLT4-binding peptides enhanced nanocarrier uptake by Schlemm's canal cells while simultaneously decreasing uptake by off-target vascular endothelial cells. Using a paired longitudinal IOP study in vivo, we show this enhanced targeting of Schlemm's canal cells translates to IOP reductions that are sustained for a significantly longer time as compared to controls. Histological analysis of murine anterior segment tissue confirmed nanocarrier localization to Schlemm's canal within one hour after intracameral administration. This work demonstrates that steric effects between surface-displayed ligands and PEG coronas significantly impact targeting performance of synthetic nanocarriers across multiple biological scales. Minimizing the obstruction of modular targeting ligands by PEG measurably improved the efficacy of glaucoma nanotherapy and is an important consideration for engineering PEGylated nanocarriers for targeted drug delivery.

scholarly journals Ocular Drug Delivery Barriers—Role of Nanocarriers in the Treatment of Anterior Segment Ocular Diseases

Pharmaceutics ◽  
2018 ◽  
Vol 10 (1) ◽  
pp. 28 ◽  
Author(s):  
Rinda Bachu ◽  
Pallabitha Chowdhury ◽  
Zahraa Al-Saedi ◽  
Pradeep Karla ◽  
Sai Boddu
Keyword(s):  
Drug Delivery ◽  
Anterior Segment ◽  
Ocular Drug Delivery ◽  
Ocular Diseases

scholarly journals TOPICAL DRUG DELIVERY FOR EFFECTIVE TREATMENT OF BACTERIAL INFECTIONS OF THE ANTERIOR SEGMENT OF THE EYE

2018 ◽  
Vol 11 (5) ◽  
pp. 13
Author(s):  
Ahmed Abd El-bary ◽  
Howida Kamal Ibrahim ◽  
Balqees Saeed Hazaa
Keyword(s):  
Drug Delivery ◽  
Bacterial Infections ◽  
Bacterial Species ◽  
Anterior Segment ◽  
Complex Nature ◽  
Eye Infections ◽  
Therapeutic Measures ◽  
Appropriate Therapy ◽  
The Right ◽  
Ocular Therapy

Anterior parts of the eye are susceptible to infections caused by different bacterial species. The use of suitable therapeutic measures in case of ocular infections can be sight saving. The appropriate therapy depends on selecting the right antibacterial as well as an efficient drug delivery system. Despite their accessibility, topical delivery of the selected antibiotic into the anterior ocular parts is still a challenging issue due to the complex nature of the eye. Ocular therapy would be significantly improved by modifying the physicochemical properties of the drug and by prolonging its pre-corneal residence time. This review will help pharmaceutical formulators to identify different parts of the eye and the corresponding bacterial infections, ocular barriers to drug delivery, and general consideration when formulating ocular drug delivery systems for the treatment of eye infections.

scholarly journals Promising therapeutic drug delivery systems for glaucoma: a comprehensive review

2020 ◽  
Vol 12 ◽  
pp. 251584142090574 ◽  
Author(s):  
Rohan B. Singh ◽  
Parul Ichhpujani ◽  
Sahil Thakur ◽  
Sumeet Jindal
Keyword(s):  
Drug Delivery ◽  
Ocular Surface ◽  
Drug Delivery Systems ◽  
Vision Loss ◽  
Anterior Segment ◽  
Systemic Circulation ◽  
Delivery Systems ◽  
Therapeutic Drug ◽  
Eye Drops ◽  
Sustained Drug Delivery

The delivery of ophthalmic drugs is challenging despite easy accessibility via the ocular surface. Topical instillation of eye drops is a relatively easy and most commonly used as a conduit for drug delivery for treating a myriad of ocular morbidities, particularly involving the anterior segment, and has an additional benefit of avoiding the first-pass metabolism while passing through the systemic circulation. The primary challenges of drug administration through traditional methods include—inadequate patient education for proper drug instillation technique, compliance, adherence, and persistence. Various dynamic (choroidal and conjunctival blood flow, lymphatic clearance, and tear dilution) and static (namely, different layers of cornea, sclera, and retina including blood aqueous and blood–retinal barriers) ocular barriers limit drug delivery to the target ocular tissues. The maintenance of the therapeutic drug levels on the ocular surface for a prolonged duration is an added challenge, thus preventing persistent delivery for longer durations. These factors result in inadequate management, leading to poor prognosis in vision loss in as many as 27% of the patients diagnosed with glaucoma. We have reviewed the research and advancements in the development of novel and well-tolerated drug delivery systems with the common goal of overcoming the factors limiting adequate drug delivery to the target tissues in glaucomatous patients with traditional techniques. In the recent past, multiple research groups have successfully designed noninvasive, sustained drug delivery systems, promoting the efficacy as well as the feasibility of delivering topical drugs to the anterior segment.

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