Editorial

Jump to: Research, Review

Open AccessEditorial

Recent Advances in Ophthalmic Drug Delivery

by

Anuj Chauhan

,

Laurence Fitzhenry

and

Ana Paula Serro

Pharmaceutics 2022, 14(10), 2075; https://doi.org/10.3390/pharmaceutics14102075 - 29 Sep 2022

Viewed by 898

Abstract

Due to population aging and to the increasing prevalence of diseases such as diabetes, chronic eye disorders such as glaucoma, age-related macular degeneration, and diabetic retinopathy have increased significantly, becoming responsible for a high percentage of blindness and vision impairment cases at a [...] Read more.

Due to population aging and to the increasing prevalence of diseases such as diabetes, chronic eye disorders such as glaucoma, age-related macular degeneration, and diabetic retinopathy have increased significantly, becoming responsible for a high percentage of blindness and vision impairment cases at a global level [...] Full article

(This article belongs to the Special Issue Recent Advances in Ophthalmic Drug Delivery)

Research

Jump to: Editorial, Review

Open AccessArticle

Cannabidiol-Loaded Mixed Polymeric Micelles of Chitosan/Poly(Vinyl Alcohol) and Poly(Methyl Methacrylate) for Trans-Corneal Delivery

by

Alejandro Sosnik

,

Ronya Ben Shabo

and

Hen Moshe Halamish

Pharmaceutics 2021, 13(12), 2142; https://doi.org/10.3390/pharmaceutics13122142 - 13 Dec 2021

Cited by 11 | Viewed by 2797

Abstract

Ocular drug delivery is challenging due to the very short drug residence time and low permeability. In this work, we produce and characterize mucoadhesive mixed polymeric micelles (PMs) made of chitosan (CS) and poly(vinyl alcohol) backbones graft-hydrophobized with short poly(methyl methacrylate) blocks and [...] Read more.

Ocular drug delivery is challenging due to the very short drug residence time and low permeability. In this work, we produce and characterize mucoadhesive mixed polymeric micelles (PMs) made of chitosan (CS) and poly(vinyl alcohol) backbones graft-hydrophobized with short poly(methyl methacrylate) blocks and use them to encapsulate cannabidiol (CBD), an anti-inflammatory cannabinoid. CBD-loaded mixed PMs are physically stabilized by ionotropic crosslinking of the CS domains with sodium tripolyphoshate and spray-drying. These mixed PMs display CBD loading capacity of 20% w/w and sizes of 100–200 nm, and spherical morphology (cryogenic-transmission electron microscopy). The good compatibility of the unloaded and CBD-loaded PMs is assessed in a human corneal epithelial cell line. Then, we confirm the permeability of CBD-free PMs and nanoencapsulated CBD in human corneal epithelial cell monolayers under liquid–liquid and air–liquid conditions. Overall, our results highlight the potential of these polymeric nanocarriers for ocular drug delivery. Full article

(This article belongs to the Special Issue Recent Advances in Ophthalmic Drug Delivery)

► Show Figures

Graphical abstract

Open AccessArticle

Poly(lactic-co-glycolic acid) Nanoparticles Encapsulating the Prenylated Flavonoid, Xanthohumol, Protect Corneal Epithelial Cells from Dry Eye Disease-Associated Oxidative Stress

by

,

,

,

,

,

,

,

,

,

Evan Benjamin Stubbs, Jr.

,

Giedrius Kalesnykas

,

Jenni Johanna Hakkarainen

,

Kelly Ann Langert

and

Simon Kaja

Pharmaceutics 2021, 13(9), 1362; https://doi.org/10.3390/pharmaceutics13091362 - 30 Aug 2021

Cited by 6 | Viewed by 2699

Abstract

Oxidative stress is a known contributor to the progression of dry eye disease pathophysiology, and previous studies have shown that antioxidant intervention is a promising therapeutic approach to reduce the disease burden and slow disease progression. In this study, we evaluated the pharmacological [...] Read more.

Oxidative stress is a known contributor to the progression of dry eye disease pathophysiology, and previous studies have shown that antioxidant intervention is a promising therapeutic approach to reduce the disease burden and slow disease progression. In this study, we evaluated the pharmacological efficacy of the naturally occurring prenylated chalconoid, xanthohumol, in preclinical models for dry eye disease. Xanthohumol acts by promoting the transcription of phase II antioxidant enzymes. In this study, xanthohumol prevented tert-butyl hydroperoxide-induced loss of cell viability in human corneal epithelial (HCE-T) cells in a dose-dependent manner and resulted in a significant increase in expression of the transcription factor nuclear factor erythroid 2-related factor 2 (Nrf2), the master regulator of phase II endogenous antioxidant enzymes. Xanthohumol-encapsulating poly(lactic-co-glycolic acid) nanoparticles (PLGA NP) were cytoprotective against oxidative stress in vitro, and significantly reduced ocular surface damage and oxidative stress-associated DNA damage in corneal epithelial cells in the mouse desiccating stress/scopolamine model for dry eye disease in vivo. PLGA NP represent a safe and efficacious drug delivery vehicle for hydrophobic small molecules to the ocular surface. Optimization of NP-based antioxidant formulations with the goal to minimize instillation frequency may represent future therapeutic options for dry eye disease and related ocular surface disease. Full article

(This article belongs to the Special Issue Recent Advances in Ophthalmic Drug Delivery)

► Show Figures

Figure 1

Open AccessArticle

A Long-Acting Curcumin Nanoparticle/In Situ Hydrogel Composite for the Treatment of Uveal Melanoma

by

,

,

and

Pharmaceutics 2021, 13(9), 1335; https://doi.org/10.3390/pharmaceutics13091335 - 25 Aug 2021

Cited by 13 | Viewed by 3022

Abstract

Uveal melanoma (UM) is the most common primary intraocular tumor in adults with high mortality. In order to improve prognosis and survival of UM patients, it is critical to inhibit tumor progression and metastasis as early as possible after the initial presentation/diagnosis of [...] Read more.

Uveal melanoma (UM) is the most common primary intraocular tumor in adults with high mortality. In order to improve prognosis and survival of UM patients, it is critical to inhibit tumor progression and metastasis as early as possible after the initial presentation/diagnosis of the disease. Sustained local delivery of antitumor therapeutics in the posterior region can potentially achieve long-term UM inhibition, improve target therapeutic delivery to the posterior segments, as well as reduce injection frequency and hence improved patient compliance. To address the highly unmet medical need in UM therapy, a bioinspired in situ gelling hydrogel system composed of naturally occurring biopolymers collagen and hyaluronic acid was developed in the present research. Curcumin with anti-cancer progression, anti-metastasis effects, and good ocular safety was chosen as the model therapeutic. The developed in situ gelling delivery system gelled at 37 °C within two minutes and demonstrated excellent biocompatibility and slow degradation. The curcumin-loaded nanoparticle/hydrogel composite was able to sustain release payload for up to four weeks. The optimized nanoparticle/hydrogel composite showed effective inhibition of human UM cell proliferation. This novel nanoparticle/in situ hydrogel composite demonstrated a great potential for the treatment of the rare and devastating intraocular cancer. Full article

(This article belongs to the Special Issue Recent Advances in Ophthalmic Drug Delivery)

► Show Figures

Graphical abstract

Open AccessArticle

Effect of Carbon Chain Length, Ionic Strength, and pH on the In Vitro Release Kinetics of Cationic Drugs from Fatty-Acid-Loaded Contact Lenses

by

,

,

,

,

,

,

and

Pharmaceutics 2021, 13(7), 1060; https://doi.org/10.3390/pharmaceutics13071060 - 10 Jul 2021

Cited by 1 | Viewed by 1930

Abstract

This paper explores the use of fatty acids in silicone hydrogel contact lenses for extending the release duration of cationic drugs. Drug release kinetics was dependent on the carbon chain length of the fatty acid loaded in the lens, with 12-, 14- and [...] Read more.

This paper explores the use of fatty acids in silicone hydrogel contact lenses for extending the release duration of cationic drugs. Drug release kinetics was dependent on the carbon chain length of the fatty acid loaded in the lens, with 12-, 14- and 18-carbon chain length fatty acids increasing the uptake and the release duration of ketotifen fumarate (KTF) and tetracaine hydrochloride (THCL). Drug release kinetics from oleic acid-loaded lenses was evaluated in phosphate buffer saline (PBS) at different ionic strengths (I = 167, 500, 1665 mM); the release duration of KTF and THCL was decreased with increasing ionic strength of the release medium. Furthermore, the release of KTF and THCL in deionized water did not show a burst and was significantly slower compared to that in PBS. The release kinetics of KTF and THCL was significantly faster when the pH of the release medium was decreased from 7.4 towards 5.5 because of the decrease in the relative amounts of oleate anions in the lens mostly populated at the polymer–pore interfaces. The use of boundary charges at the polymer–pore interfaces of a contact lens to enhance drug partition and extend its release is further confirmed by loading cationic phytosphingosine in contact lenses to attract an anionic drug. Full article

(This article belongs to the Special Issue Recent Advances in Ophthalmic Drug Delivery)

► Show Figures

Graphical abstract

Open AccessEditor’s ChoiceArticle

Dexamethasone-Loaded Nanostructured Lipid Carriers for the Treatment of Dry Eye Disease

by

,

,

,

,

,

,

,

,

and

Pharmaceutics 2021, 13(6), 905; https://doi.org/10.3390/pharmaceutics13060905 - 18 Jun 2021

Cited by 17 | Viewed by 3487

Abstract

Dry eye disease (DED) or keratoconjunctivitis sicca is a chronic multifactorial disorder of the ocular surface caused by tear film dysfunction. Symptoms include dryness, irritation, discomfort and visual disturbance, and standard treatment includes the use of lubricants and topical steroids. Secondary inflammation plays [...] Read more.

Dry eye disease (DED) or keratoconjunctivitis sicca is a chronic multifactorial disorder of the ocular surface caused by tear film dysfunction. Symptoms include dryness, irritation, discomfort and visual disturbance, and standard treatment includes the use of lubricants and topical steroids. Secondary inflammation plays a prominent role in the development and propagation of this debilitating condition. To address this we have investigated the pilot scale development of an innovative drug delivery system using a dexamethasone-encapsulated cholesterol-Labrafac™ lipophile nanostructured lipid carrier (NLC)-based ophthalmic formulation, which could be developed as an eye drop to treat DED and any associated acute exacerbations. After rapid screening of a range of laboratory scale pre-formulations, the chosen formulation was prepared at pilot scale with a particle size of 19.51 ± 0.5 nm, an encapsulation efficiency of 99.6 ± 0.5%, a PDI of 0.08, and an extended stability of 6 months at 4 °C. This potential ophthalmic formulation was observed to have high tolerability and internalization capacity for human corneal epithelial cells, with similar behavior demonstrated on ex vivo porcine cornea studies, suggesting suitable distribution on the ocular surface. Further, ELISA was used to study the impact of the pilot scale formulation on a range of inflammatory biomarkers. The most successful dexamethasone-loaded NLC showed a 5-fold reduction of TNF-α production over dexamethasone solution alone, with comparable results for MMP-9 and IL-6. The ease of formulation, scalability, performance and biomarker assays suggest that this NLC formulation could be a viable option for the topical treatment of DED. Full article

(This article belongs to the Special Issue Recent Advances in Ophthalmic Drug Delivery)

► Show Figures

Figure 1

Open AccessArticle

Asymmetry in Drug Permeability through the Cornea

by

Nadia Toffoletto

,

Anuj Chauhan

,

Carmen Alvarez-Lorenzo

,

Benilde Saramago

and

Ana Paula Serro

Pharmaceutics 2021, 13(5), 694; https://doi.org/10.3390/pharmaceutics13050694 - 11 May 2021

Cited by 6 | Viewed by 2093

Abstract

The permeability through the cornea determines the ability of a drug or any topically applied compound to cross the tissue and reach the intraocular area. Most of the permeability values found in the literature are obtained considering topical drug formulations, and therefore, refer [...] Read more.

The permeability through the cornea determines the ability of a drug or any topically applied compound to cross the tissue and reach the intraocular area. Most of the permeability values found in the literature are obtained considering topical drug formulations, and therefore, refer to the drug permeability inward the eye. However, due to the asymmetry of the corneal tissue, outward drug permeability constitutes a more meaningful parameter when dealing with intraocular drug-delivery systems (i.e., drug-loaded intraocular lenses, intraocular implants or injections). Herein, the permeability coefficients of two commonly administered anti-inflammatory drugs (i.e., bromfenac sodium and dexamethasone sodium) were determined ex vivo using Franz diffusion cells and porcine corneas in both inward and outward configurations. A significantly higher drug accumulation in the cornea was detected in the outward direction, which is consistent with the different characteristics of the corneal layers. Coherently, a higher permeability coefficient was obtained for bromfenac sodium in the outward direction, but no differences were detected for dexamethasone sodium in the two directions. Drug accumulation in the cornea can prolong the therapeutic effect of intraocular drug-release systems. Full article

(This article belongs to the Special Issue Recent Advances in Ophthalmic Drug Delivery)

► Show Figures

Graphical abstract

Open AccessArticle

Resveratrol-Loaded Hydrogel Contact Lenses with Antioxidant and Antibiofilm Performance

by

,

,

,

,

,

and

Carmen Alvarez-Lorenzo

Pharmaceutics 2021, 13(4), 532; https://doi.org/10.3390/pharmaceutics13040532 - 11 Apr 2021

Cited by 14 | Viewed by 3534

Abstract

Contact lenses (CLs) are prone to biofilm formation, which may cause severe ocular infections. Since the use of antibiotics is associated with resistance concerns, here, two alternative strategies were evaluated to endow CLs with antibiofilm features: copolymerization with the antifouling monomer 2-methacryloyloxyethyl phosphorylcholine [...] Read more.

Contact lenses (CLs) are prone to biofilm formation, which may cause severe ocular infections. Since the use of antibiotics is associated with resistance concerns, here, two alternative strategies were evaluated to endow CLs with antibiofilm features: copolymerization with the antifouling monomer 2-methacryloyloxyethyl phosphorylcholine (MPC) and loading of the antioxidant resveratrol with known antibacterial activity. MPC has, so far, been used to increase water retention on the CL surface (Proclear^® 1 day CLs). Both poly(hydroxyethyl methacrylate) (HEMA) and silicone hydrogels were prepared with MPC covering a wide range of concentrations (from 0 to 101 mM). All hydrogels showed physical properties adequate for CLs and successfully passed the hen’s egg-chorioallantoic membrane (HET-CAM) test. Silicone hydrogels had stronger affinity for resveratrol, with higher loading and a slower release rate. Ex vivo cornea and sclera permeability tests revealed that resveratrol released from the hydrogels readily accumulated in both tissues but did not cross through. The antibiofilm tests against Pseudomonas aeruginosa and Staphylococcus aureus evidenced that, in general, resveratrol decreased biofilm formation, which correlated with its concentration-dependent antibacterial capability. Preferential adsorption of lysozyme, compared to albumin, might also contribute to the antimicrobial activity. In addition, importantly, the loading of resveratrol in the hydrogels preserved the antioxidant activity, even against photodegradation. Overall, the designed hydrogels can host therapeutically relevant amounts of resveratrol to be sustainedly released on the eye, providing antibiofilm and antioxidant performance. Full article

(This article belongs to the Special Issue Recent Advances in Ophthalmic Drug Delivery)

► Show Figures

Graphical abstract

Open AccessArticle

Enhanced Transport and Permeation of a Polymeric Nanocarrier across the Retina by Mixing with ATP upon Intravitreal Injection

by

,

,

and

Pharmaceutics 2021, 13(4), 463; https://doi.org/10.3390/pharmaceutics13040463 - 29 Mar 2021

Cited by 1 | Viewed by 1137

Abstract

The outer part of the retina pigment epithelium (RPE) in the retina is the main site of neovascularization associated with retinal diseases. However, various obstacles interrupt the delivery of medicines across the RPE, mainly due to the well-developed tight junctions in the RPE. [...] Read more.

The outer part of the retina pigment epithelium (RPE) in the retina is the main site of neovascularization associated with retinal diseases. However, various obstacles interrupt the delivery of medicines across the RPE, mainly due to the well-developed tight junctions in the RPE. Currently, there is no practical formulation to overcome this issue. In this study, we demonstrated that simple mixing with adenosine tetraphosphate (ATP) has the potential to greatly enhance the transport and permeation of a polymeric nanocarrier across the retina via intravitreal administration. Chitosan-functionalized, pluronic-based nanocarrier (NC), which can deliver various biomolecules efficiently, was used as a polymeric nanocarrier. Mixing with ATP facilitated the diffusion of the nanocarrier in the vitreous humor by reducing the electrostatic interaction between NC and negatively charged glycosaminoglycans (GAGs) in the vitreous humor. Mixing with ATP also allowed the penetration of NC across the whole retina, and it resulted in a great increase (approximately nine times) in the transport of NC across the retina, as well as spreading it throughout the whole retina upon intravitreal administration in a mouse model. This enhanced permeation across the retina was specific to ATP but not to GTP, suggesting the possibility of P2Y receptor-mediated tight junction disruption by ATP. Full article

(This article belongs to the Special Issue Recent Advances in Ophthalmic Drug Delivery)

► Show Figures

Graphical abstract

Open AccessArticle

Monitoring New Long-Lasting Intravitreal Formulation for Glaucoma with Vitreous Images Using Optical Coherence Tomography

by

Maria Jesus Rodrigo

,

Amaya Pérez del Palomar

,

Alberto Montolío

,

Silvia Mendez-Martinez

,

Manuel Subias

,

Maria Jose Cardiel

,

Teresa Martinez-Rincon

,

,

,

,

,

and

Pharmaceutics 2021, 13(2), 217; https://doi.org/10.3390/pharmaceutics13020217 - 05 Feb 2021

Cited by 4 | Viewed by 1461

Abstract

Intravitreal injection is the gold standard therapeutic option for posterior segment pathologies, and long-lasting release is necessary to avoid reinjections. There is no effective intravitreal treatment for glaucoma or other optic neuropathies in daily practice, nor is there a non-invasive method to monitor [...] Read more.

Intravitreal injection is the gold standard therapeutic option for posterior segment pathologies, and long-lasting release is necessary to avoid reinjections. There is no effective intravitreal treatment for glaucoma or other optic neuropathies in daily practice, nor is there a non-invasive method to monitor drug levels in the vitreous. Here we show that a glaucoma treatment combining a hypotensive and neuroprotective intravitreal formulation (IF) of brimonidine–Laponite (BRI/LAP) can be monitored non-invasively using vitreoretinal interface imaging captured with optical coherence tomography (OCT) over 24 weeks of follow-up. Qualitative and quantitative characterisation was achieved by analysing the changes in vitreous (VIT) signal intensity, expressed as a ratio of retinal pigment epithelium (RPE) intensity. Vitreous hyperreflective aggregates mixed in the vitreous and tended to settle on the retinal surface. Relative intensity and aggregate size progressively decreased over 24 weeks in treated rat eyes as the BRI/LAP IF degraded. VIT/RPE relative intensity and total aggregate area correlated with brimonidine levels measured in the eye. The OCT-derived VIT/RPE relative intensity may be a useful and objective marker for non-invasive monitoring of BRI/LAP IF. Full article

(This article belongs to the Special Issue Recent Advances in Ophthalmic Drug Delivery)

► Show Figures

Graphical abstract

Review

Jump to: Editorial, Research

Open AccessEditor’s ChoiceReview

Lipid-Based Nanocarriers for Ophthalmic Administration: Towards Experimental Design Implementation

by

Felipe M. González-Fernández

,

,

,

and

Pharmaceutics 2021, 13(4), 447; https://doi.org/10.3390/pharmaceutics13040447 - 26 Mar 2021

Cited by 24 | Viewed by 3591

Abstract

Nanotherapeutics based on biocompatible lipid matrices allow for enhanced solubility of poorly soluble compounds in the treatment of ophthalmic diseases, overcoming the anatomical and physiological barriers present in the eye, which, despite the ease of access, remains strongly protected. Micro-/nanoemulsions, solid lipid nanoparticles [...] Read more.

Nanotherapeutics based on biocompatible lipid matrices allow for enhanced solubility of poorly soluble compounds in the treatment of ophthalmic diseases, overcoming the anatomical and physiological barriers present in the eye, which, despite the ease of access, remains strongly protected. Micro-/nanoemulsions, solid lipid nanoparticles (SLN) or nanostructured lipid carriers (NLC) combine liquid and/or solid lipids with surfactants, improving drug stability and ocular bioavailability. Current research and development approaches based on try-and-error methodologies are unable to easily fine-tune nanoparticle populations in order to overcome the numerous constraints of ocular administration routes, which is believed to hamper easy approval from regulatory agencies for these systems. The predictable quality and specifications of the product can be achieved through quality-by-design (QbD) implementation in both research and industrial environments, in contrast to the current quality-by-testing (QbT) framework. Mathematical modelling of the expected final nanoparticle characteristics by variation of operator-controllable variables of the process can be achieved through adequate statistical design-of-experiments (DoE) application. This multivariate approach allows for optimisation of drug delivery platforms, reducing research costs and time, while maximising the understanding of the production process. This review aims to highlight the latest efforts in implementing the design of experiments to produce optimised lipid-based nanocarriers intended for ophthalmic administration. A useful background and an overview of the different possible approaches are presented, serving as a starting point to introduce the design of experiments in current nanoparticle research. Full article

(This article belongs to the Special Issue Recent Advances in Ophthalmic Drug Delivery)

► Show Figures

Graphical abstract

Open AccessEditor’s ChoiceReview

Suprachoroidal Delivery of Small Molecules, Nanoparticles, Gene and Cell Therapies for Ocular Diseases

by

,

,

and

Pharmaceutics 2021, 13(2), 288; https://doi.org/10.3390/pharmaceutics13020288 - 22 Feb 2021

Cited by 23 | Viewed by 5526

Abstract

Suprachoroidal drug delivery technology has advanced rapidly and emerged as a promising administration route for a variety of therapeutic candidates, in order to target multiple ocular diseases, ranging from neovascular age-related macular degeneration to choroidal melanoma. This review summarizes the latest preclinical and [...] Read more.

Suprachoroidal drug delivery technology has advanced rapidly and emerged as a promising administration route for a variety of therapeutic candidates, in order to target multiple ocular diseases, ranging from neovascular age-related macular degeneration to choroidal melanoma. This review summarizes the latest preclinical and clinical progress in suprachoroidal delivery of therapeutic agents, including small molecule suspensions, polymeric entrapped small molecules, gene therapy (viral and nonviral nanoparticles), viral nanoparticle conjugates (VNCs), and cell therapy. Formulation customization is critical in achieving favorable pharmacokinetics, and sustained drug release profiles have been repeatedly observed for multiple small molecule suspensions and polymeric formulations. Novel therapeutic agents such as viral and nonviral gene therapy, as well as VNCs, have demonstrated promise in animal studies. Several of these suprachoroidally-administered therapies have been assessed in clinical trials, including small molecule suspensions of triamcinolone acetonide and axitinib, viral vector RGX-314 for gene therapy, and VNC AU-011. With continued drug delivery research and optimization, coupled with customized drug formulations, suprachoroidal drug delivery may address large unmet therapeutic needs in ophthalmology, targeting affected tissues with novel therapies for efficacy benefits, compartmentalizing therapies away from unaffected tissues for safety benefits, and achieving durability to relieve the treatment burden noted with current agents. Full article

(This article belongs to the Special Issue Recent Advances in Ophthalmic Drug Delivery)

► Show Figures

Figure 1

Open AccessReview

Therapeutic Ophthalmic Lenses: A Review

by

Nadia Toffoletto

,

Benilde Saramago

and

Ana Paula Serro

Pharmaceutics 2021, 13(1), 36; https://doi.org/10.3390/pharmaceutics13010036 - 28 Dec 2020

Cited by 19 | Viewed by 4721

Abstract

An increasing incidence of eye diseases has been registered in the last decades in developed countries due to the ageing of population, changes in lifestyle, environmental factors, and the presence of concomitant medical conditions. The increase of public awareness on ocular conditions leads [...] Read more.

An increasing incidence of eye diseases has been registered in the last decades in developed countries due to the ageing of population, changes in lifestyle, environmental factors, and the presence of concomitant medical conditions. The increase of public awareness on ocular conditions leads to an early diagnosis and treatment, as well as an increased demand for more effective and minimally invasive solutions for the treatment of both the anterior and posterior segments of the eye. Despite being the most common route of ophthalmic drug administration, eye drops are associated with compliance issues, drug wastage by lacrimation, and low bioavailability due to the ocular barriers. In order to overcome these problems, the design of drug-eluting ophthalmic lenses constitutes a non-invasive and patient-friendly approach for the sustained drug delivery to the eye. Several examples of therapeutic contact lenses and intraocular lenses have been developed, by means of different strategies of drug loading, leading to promising results. This review aims to report the recent advances in the development of therapeutic ophthalmic lenses for the treatment and/or prophylaxis of eye pathologies (i.e., glaucoma, cataract, corneal diseases, or posterior segment diseases) and it gives an overview of the future perspectives and challenges in the field. Full article

(This article belongs to the Special Issue Recent Advances in Ophthalmic Drug Delivery)

► Show Figures

Graphical abstract

Open AccessReview

Novel Drug Delivery Systems Fighting Glaucoma: Formulation Obstacles and Solutions

by

,

,

,

,

,

and

Pharmaceutics 2021, 13(1), 28; https://doi.org/10.3390/pharmaceutics13010028 - 26 Dec 2020

Cited by 24 | Viewed by 6862

Abstract

Glaucoma is considered to be one of the biggest health problems in the world. It is the main cause of preventable blindness due to its asymptomatic nature in the early stages on the one hand and patients’ non-adherence on the other. There are [...] Read more.

Glaucoma is considered to be one of the biggest health problems in the world. It is the main cause of preventable blindness due to its asymptomatic nature in the early stages on the one hand and patients’ non-adherence on the other. There are several approaches in glaucoma treatment, whereby this has to be individually designed for each patient. The first-line treatment is medication therapy. However, taking into account numerous disadvantages of conventional ophthalmic dosage forms, intensive work has been carried out on the development of novel drug delivery systems for glaucoma. This review aims to provide an overview of formulation solutions and strategies in the development of in situ gel systems, nanosystems, ocular inserts, contact lenses, collagen corneal shields, ocular implants, microneedles, and iontophoretic devices. The results of studies confirming the effectiveness of the aforementioned drug delivery systems were also briefly presented. Full article

(This article belongs to the Special Issue Recent Advances in Ophthalmic Drug Delivery)

► Show Figures

Graphical abstract

Open AccessReview

Recent Research in Ocular Cystinosis: Drug Delivery Systems, Cysteamine Detection Methods and Future Perspectives

by

Ana Castro-Balado

,

Cristina Mondelo-García

,

Iria Varela-Rey

,

Beatriz Moreda-Vizcaíno

,

Jesús F. Sierra-Sánchez

,

María Teresa Rodríguez-Ares

,

Gonzalo Hermelo-Vidal

,

Irene Zarra-Ferro

,

Miguel González-Barcia

,

Eva Yebra-Pimentel

,

María Jesús Giráldez-Fernández

,

Francisco J. Otero-Espinar

and

Anxo Fernández-Ferreiro

Pharmaceutics 2020, 12(12), 1177; https://doi.org/10.3390/pharmaceutics12121177 - 03 Dec 2020

Cited by 6 | Viewed by 2506

Abstract

Cystinosis is a rare genetic disorder characterized by the accumulation of cystine crystals in different tissues and organs. Although renal damage prevails during initial stages, the deposition of cystine crystals in the cornea causes severe ocular manifestations. At present, cysteamine is the only [...] Read more.

Cystinosis is a rare genetic disorder characterized by the accumulation of cystine crystals in different tissues and organs. Although renal damage prevails during initial stages, the deposition of cystine crystals in the cornea causes severe ocular manifestations. At present, cysteamine is the only topical effective treatment for ocular cystinosis. The lack of investment by the pharmaceutical industry, together with the limited stability of cysteamine, make it available only as two marketed presentations (Cystaran^® and Cystadrops^®) and as compounding formulations prepared in pharmacy departments. Even so, new drug delivery systems (DDSs) need to be developed, allowing more comfortable dosage schedules that favor patient adherence. In the last decades, different research groups have focused on the development of hydrogels, nanowafers and contact lenses, allowing a sustained cysteamine release. In parallel, different determination methods and strategies to increase the stability of the formulations have also been developed. This comprehensive review aims to compile all the challenges and advances related to new cysteamine DDSs, analytical determination methods, and possible future therapeutic alternatives for treating cystinosis. Full article

(This article belongs to the Special Issue Recent Advances in Ophthalmic Drug Delivery)

► Show Figures

Figure 1

Journal Menu

Journal Browser

Special Issue "Recent Advances in Ophthalmic Drug Delivery"

Share This Special Issue

Special Issue Editors

Special Issue Information

Keywords

Published Papers (15 papers)

Editorial

Research

Review

Further Information

Guidelines

MDPI Initiatives

Follow MDPI