Intravitreal methotrexate and fluocinolone acetonide implantation for Vogt-Koyanagi-Harada uveitis

Intravitreal immunotherapy in non-infectious uveitis: an update

INTRODUCTION

In the past several years, there have been numerous advances in pharmacotherapeutics for the management of uveitis and other ocular inflammatory diseases, including newer therapeutic agents and ocular drug delivery systems. One of the most attractive modes of drug delivery is the intravitreal route since it has proven to be safe and efficacious and prevents unwanted systemic adverse events related to the agent.

AREAS COVERED

In this review, intravitreal delivery of various pharmacotherapeutic agents for noninfectious uveitis has been described. An extensive review of the literature was performed using specific keywords on the PubMed database to identify clinical studies employing various pharmacotherapeutic agents with intravitreal drug delivery for noninfectious uveitis. The mode of action, safety, efficacy, and tolerability of these drugs have also been elucidated.

EXPERT OPINION

Several agents, including biologic response modifier agents, have been found to be safe and efficacious for various indications of uveitis, such as cystoid macular edema, active uveitis, and other conditions such as retinal vasculitis and vitreous haze. The use of intravitreal biological therapies, especially infliximab, has been fraught with potential safety signals such as photoreceptor toxicity. However, pharmacotherapeutic agents such as corticosteroids and anti-vascular endothelial growth factor agents are now widely used in the clinical management of uveitis and its complications.

Overcoming Treatment Challenges in Posterior Segment Diseases with Biodegradable Nano-Based Drug Delivery Systems

Posterior segment eye diseases present a challenge in treatment due to the complex structures in the eye that serve as robust static and dynamic barriers, limiting the penetration, residence time, and bioavailability of topical and intraocular medications. This hinders effective treatment and requires frequent dosing, such as the regular use of eye drops or visits to the ophthalmologist for intravitreal injections, to manage the disease. Moreover, the drugs must be biodegradable to minimize toxicity and adverse reactions, as well as small enough to not affect the visual axis. The development of biodegradable nano-based drug delivery systems (DDSs) can be the solution to these challenges. First, they can stay in ocular tissues for longer periods of time, reducing the frequency of drug administration. Second, they can pass through ocular barriers, offering higher bioavailability to targeted tissues that are otherwise inaccessible. Third, they can be made up of polymers that are biodegradable and nanosized. Hence, therapeutic innovations in biodegradable nanosized DDS have been widely explored for ophthalmic drug delivery applications. In this review, we will present a concise overview of DDSs utilized in the treatment of ocular diseases. We will then examine the current therapeutic challenges faced in the management of posterior segment diseases and explore how various types of biodegradable nanocarriers can enhance our therapeutic arsenal. A literature review of the pre-clinical and clinical studies published between 2017 and 2023 was conducted. Through the advances in biodegradable materials, combined with a better understanding of ocular pharmacology, the nano-based DDSs have rapidly evolved, showing great promise to overcome challenges currently encountered by clinicians.

A comprehensive review of intravitreal immunosuppressants and biologicals used in ophthalmology

Systemic immunosuppressants and biologicals have been a valuable tool in the treatment of inflammatory diseases and malignancies. The safety profile of these drugs has been debatable, especially in localized systems, such as the eye. This has led to the search for fairly local approaches, such as intravitreal, subconjunctival, and topical route of administration. Immunosuppressants have been used as a second-line drug in patients intolerable to corticosteroids or those who develop multiple recurrences on weaning corticosteroids. Similarly, biologicals have also been used as the next line of therapy, when adequate control of inflammation could not be attained or immunosuppressants were contraindicated to patients. Intravitreal immunosuppressants, such as methotrexate and sirolimus, have been extensively studied in noninfectious posterior uveitis, whereas limited studies have established the efficacy of intravitreal biologicals, such as infliximab and adalimumab. Most of these drugs have shown good safety profile and tolerability in animal studies alone and have not been studied further in human subjects. However, most of the studies in literature are single-case reports or case series which limits the level of evidence. In this comprehensive review, we discuss the mechanism of action, pharmacodynamics, pharmacokinetics, indications, efficacy, and side effects of different intravitreal immunosuppressants and biologicals that have been studied in literature.

Recent advances in ophthalmic preparations: Ocular barriers, dosage forms and routes of administration

The human eye is a complex organ with unique anatomy and physiology that restricts the delivery of drugs to target ocular tissues/sites. Recent advances in the field of pharmacy, biotechnology and material science have led to development of novel ophthalmic dosage forms which can provide sustained drug delivery, reduce dosing frequency and improve the ocular bioavailability of drugs. This review highlights the different anatomical and physiological factors which affect ocular bioavailability of drugs and explores advancements from 2016 to 2020 in various ophthalmic preparations. Different routes of drug administration such as topical, intravitreal, intraocular, juxtascleral, subconjunctival, intracameral and retrobulbar are discussed with their advances and limitations.