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

Abstract

Ocular drug delivery is challenging due to the presence of anatomical and physiological barriers. These barriers can affect drug entry into the eye following multiple routes of administration (e.g., topical, systemic, and injectable). Topical administration in the form of eye drops is preferred for treating anterior segment diseases, as it is convenient and provides local delivery of drugs. Major concerns with topical delivery include poor drug absorption and low bioavailability. To improve the bioavailability of topically administered drugs, novel drug delivery systems are being investigated. Nanocarrier delivery systems demonstrate enhanced drug permeation and prolonged drug release. This review provides an overview of ocular barriers to anterior segment delivery, along with ways to overcome these barriers using nanocarrier systems. The disposition of nanocarriers following topical administration, their safety, toxicity and clinical trials involving nanocarrier systems are also discussed.

Assembling Surfactants-Mucoadhesive Polymer Nanomicelles (ASMP-Nano) for Ocular Delivery of Cyclosporine-A

“…Micellization generally occurs when the intermolecular forces, such as hydrophobic, steric, electrostatic, hydrogen bonding and Van der Waals forces are balanced. Other factors that affect the assembling of micelles include the shape, charge and size of surfactant monomers, ionic strength, pH, temperature, total surfactant concentration and the composition of the surfactants' mixtures [24,25]. The nanomicelles favour solubilisation processes by sequestering the drug in the lipophilic core, formed by the non-polar tails of the surfactant, and interacting with the hydrophilic environment through an outer shell consisting of polar or charged heads.…”

Metal–Organic Frameworks as Drug Delivery Platforms for Ocular Therapeutics

“…%) and fast release of the drug (within minutes/hours). [10][11][12] These numbers can be improved through the incorporation of denser inorganic matrices in the formulation, for instance montmorillonite clay and layered double hydroxides (LDH). 13,14 Montmorillonite/chitosan nanoparticles have been evaluated as delivery systems for betaxolol hydrochloride, a selective beta-adrenergic blocking agent, with excellent values of drug loading capacity (up to 14.5 wt.%) and delivery kinetics between 6-10h.…”

Tunneling Nanotubes and the Eye: Intercellular Communication and Implications for Ocular Health and Disease

“…A growing area of ocular research concerns the delivery of drugs and gene therapies [128][129][130][131]. Many papers have described the use of nanoparticles as drug delivery systems, which offer attractive advantages over conventional methods including targeted delivery, increased drug bioavailability with lower doses, sustained release, and reduced side effects [132].…”