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

Iris atrophy following intracameral dexamethasone injection: a report of two pediatric cases

We report 2 pediatric cases of iris atrophy that developed roughly 1 month after intracameral injection of dexamethasone suspension 9% following unilateral goniotomy and cataract extraction.

Recent advances and future prospects: current status and challenges of the intraocular injection of drugs for vitreoretinal diseases

Effective drug therapy for vitreoretinal disease is a major challenge in the field of ophthalmology; various protective systems, including anatomical and physiological barriers, complicate drug delivery to precise targets. However, as the eye is a closed cavity, it is an ideal target for local administration. Various types of drug delivery systems have been investigated that take advantage of this aspect of the eye, enhancing ocular permeability and optimizing local drug concentrations. Many drugs, mainly anti-VEGF drugs, have been evaluated in clinical trials and have provided clinical benefit to many patients. In the near future, innovative drug delivery systems will be developed to avoid frequent intravitreal administration of drugs and maintain effective drug concentrations for a long period of time. Here, we review the published literature on various drugs and administration routes and current clinical applications. Recent advances in drug delivery systems are discussed along with future prospects.

Identifying and addressing common contributors to nonadherence with ophthalmic medical therapy

PURPOSE OF REVIEW

To discuss common reasons for nonadherence and review existing and emerging options to reduce nonadherence with ocular medical therapy and optimize therapeutic outcomes.

RECENT FINDINGS

Nonadherence can arise from patient-related issues (e.g. physical, cognitive) and healthcare-related issues (e.g. cost, access to care). Multiple strategies have been developed and evaluated to overcome these barriers to adherence. Identifying nonadherence and its cause(s) facilitates the development of strategies to overcome it.

SUMMARY

Many common causes of nonadherence can be mitigated through a variety of strategies presented.

The double-edged sword of inflammation in inherited retinal degenerations: Clinical and preclinical evidence for mechanistically and prognostically impactful but treatable complications

We present retrospective data from our clinical research efforts of the past several years alongside a review of past and current clinical and preclinical data independently by several investigators supporting our clinical evidence for the importance of inflammation in inherited retinal degenerations (IRDs). We show how inflammation is a complicating factor in IRDs but, if recognized and managed, also a great opportunity to mitigate disease severity immediately, improve patient prognosis and quality of life, extend the treatment windows for gene-specific and agnostic therapeutic approaches, mitigate the impact of inflammatory complications on the accurate estimate of vision changes in IRD natural history studies, improve the chances of safer outcomes following cataract surgery, and potentially reduce the likelihood of inflammatory adverse events and augment the efficacy of viral vector-based treatment approaches to IRDs. Manuscript contribution to the field. Inflammation has been suspected to be at play in IRDs since the beginning of the 1900s and became a research focus through the early 1990s but was then largely abandoned in favor of genetic-focused research. Thanks to regained cognizance, better research tools, and a more holistic approach to IRDs, the recent reappraisal of the role of inflammation in IRDs has brought back to the surface its importance. A potential confounder in natural history studies and a limiting factor in clinical trials if not accounted for, inflammation can be managed and often offers an opportunity for immediately improved prognosis and outcomes for IRD patients. We present our retrospective clinical evidence for connections with a measurable secondary autoimmune component that can develop in IRDs and contribute to vision loss but is at least in part treatable. We also present ample lines of evidence from the literature corroborating our clinical observations at the preclinical level.

Therapeutic Potential of d-MAPPS™ for Ocular Inflammatory Diseases and Regeneration of Injured Corneal and Retinal Tissue

The invasion of microbial pathogens and/or sterile inflammation caused by physical/chemical injuries, increased ocular pressure, oxidative stress, and ischemia could lead to the generation of detrimental immune responses in the eyes, which result in excessive tissue injury and vision loss. The bioavailability of eye drops that are enriched with immunoregulatory and trophic factors which may concurrently suppress intraocular inflammation and promote tissue repair and regeneration is generally low. We recently developed “derived- Multiple Allogeneic Proteins Paracrine Signaling regenerative biologics platform technology d-MAPPS™”, a bioengineered biological product which is enriched with immunomodulatory and trophic factors that can efficiently suppress detrimental immune responses in the eye and promote the repair and regeneration of injured corneal and retinal tissues. The results obtained in preclinical and clinical studies showed that d-MAPPS™ increased the viability of injured corneal cells, inhibited the production of inflammatory cytokines in immune cells, alleviated inflammation, and restored vision loss in patients suffering from meibomian gland dysfunction and dry eye disease. Herewith, we emphasized molecular mechanisms responsible for the therapeutic efficacy of d-MAPPS™ and we presented the main beneficial effects of d-MAPPS™ in clinical settings, indicating that the topical administration of d-MAPPS™ could be considered a new therapeutic approach for the treatment of ocular inflammatory diseases and for the repair and regeneration of injured corneal and retinal tissues.

Recent achievements in nano-based technologies for ocular disease diagnosis and treatment, review and update

Ocular drug delivery is one of the most challenging endeavors among the various available drug delivery systems. Despite having suitable drugs for the treatment of ophthalmic disease, we have not yet succeeded in achieving a proper drug delivery approach with the least adverse effects. Nanotechnology offers great opportunities to overwhelm the restrictions of common ocular delivery systems, including low therapeutic effects and adverse effects because of invasive surgery or systemic exposure. The present review is dedicated to highlighting and updating the recent achievements of nano-based technologies for ocular disease diagnosis and treatment. While further effort remains, the progress illustrated here might pave the way to new and very useful ocular nanomedicines.

Nanotechnology-based formulations to amplify intraocular bioavailability

Conventional drug delivery formulations, such as eye drops and ointments, are mainly administered by topical instillation. The topical delivery of ophthalmic drugs is a challenging endeavor despite the eye is easily accessible. Unique and complex barriers, serving as protection against extrinsic harmful factors, hamper therapeutic intraocular drug concentrations. Bioavailability for deeper ocular tissues of the anterior segment of the eye is exceptionally low. As the bioavailability of the active substance is the major hurdle to overcome, dosing is increased, so the side effects do. Both provoke patient poor compliance, confining the desired therapeutic outcome. The incidence and severity of adverse reactions amplify evenly in the case of chronic treatments. Current research focuses on the development of innovative delivery strategies to address low ocular bioavailability and provide safe and convenient dosing schemes. The main objective of this review is to explore and present the latest developments in ocular drug delivery formulations for the treatment of the pathology of the anterior segment of the eye. Nanotechnology-based formulations, that is, organic nanoparticles (liposomes, niosomes/discosomes, dendrimers, nanoemulsions, nanosuspensions, nanoparticles/nanospheres) and inorganic nanoparticles, nanoparticle-laden therapeutic contact lenses, in situ gelling systems, and ocular inserts, are summarized and presented accordingly.

Nanodelivery of triamcinolone acetonide with PLGA-chitosan nanoparticles for the treatment of ocular inflammation

Triamcinolone acetonide (TA) is widely indicated in the treatment of several ocular disorders, but the free drug suspension limits its clinical benefits and commercial compositions cause adverse ocular effects. In this study, TA was formulated in poly(d,l-lactide-co-glycolide) (PLGA)-chitosan (PLC) nanoparticles (NPs) for the treatment of ocular inflammatory diseases. TA-loaded PLC NPs exhibited excellent anti-inflammatory activity against human corneal epithelial (HCE) cells and significantly reduced the secretion of interleukin (IL)-6 in tumour necrosis factor (TNF)-α activated cells. In a rabbit model, TA-loaded PLC NPs did not show any typical clinical signs of eye inflammation and significantly alleviated inflammatory signs, compared with free TA suspension, at 24 h after a single dose. TA-loaded PLC NPs exhibited a greater aqueous humour transparency (%AHT), compared with that of normal saline (NS) or free TA suspension, indicating reduction in anterior chamber fogginess. Pharmacokinetic analysis of rabbit eyes revealed that TA-loaded PLC NPs peaked at 6 h. Substantial concentrations of TA were observed until 24 h, indicating the superiority of this PLC-based nanocarrier system. Overall, PLC-based NP formulations offer a new approach for the treatment of ocular inflammatory diseases.

mRNA-Based Nanomedicinal Products to Address Corneal Inflammation by Interleukin-10 Supplementation

The anti-inflammatory cytokine Interleukin-10 (IL-10) is considered an efficient treatment for corneal inflammation, in spite of its short half-life and poor eye bioavailability. In the present work, mRNA-based nanomedicinal products based on solid lipid nanoparticles (SLNs) were developed in order to produce IL-10 to treat corneal inflammation. mRNA encoding green fluorescent protein (GFP) or human IL-10 was complexed with different SLNs and ligands. After, physicochemical characterization, transfection efficacy, intracellular disposition, cellular uptake and IL-10 expression of the nanosystems were evaluated in vitro in human corneal epithelial (HCE-2) cells. Energy-dependent mechanisms favoured HCE-2 transfection, whereas protein production was influenced by energy-independent uptake mechanisms. Nanovectors with a mean particle size between 94 and 348 nm and a positive superficial charge were formulated as eye drops containing 1% (w/v) of polyvinyl alcohol (PVA) with 7.1-7.5 pH. After three days of topical administration to mice, all formulations produced GFP in the corneal epithelium of mice. SLNs allowed the obtaining of a higher transfection efficiency than naked mRNA. All formulations produce IL-10, and the interleukin was even observed in the deeper layers of the epithelium of mice depending on the formulation. This work shows the potential application of mRNA-SLN-based nanosystems to address corneal inflammation by gene augmentation therapy.