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

Abstract

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.

Hard, Soft, and Hard-and-Soft Drug Delivery Carriers Based on CaCO3 and Alginate Biomaterials: Synthesis, Properties, Pharmaceutical Applications

“…Eye drops are the most prevalent administered ocular medications, but they are difficult to retain in the tear film for long periods and have insufficient contact with epithelial cells [ 252 ]. Previously, superoxide dismutase (SOD), a drug for the treatment of various eye diseases related to oxidative stress, has been extensively studied in combination with various organic carriers [ 253 ].…”

Nanoparticles in ocular applications and their potential toxicity

“…Currently, the delivery system of NPs focuses on how to improve the bioavailability, targeting, stability, penetrability, and controllability of drugs (Diebold and Calonge 2010;Madni, Rahem et al, 2017;Srinivasarao, Lohiya et al, 2019). Nanomedicine carriers, such as polymer NPs (Imperiale, Acosta et al, 2018;Begines, Ortiz et al, 2020;Swetledge, Jung et al, 2021), nanomicelles (Grimaudo, Pescina et al, 2019;Durgun, Güngör et al, 2020), liposomes (Khosa, Reddi et al, 2018;Bhattacharjee, Das et al, 2019), quantum dots (Santana, Mansur et al, 2020), nanoemulsion , and inorganic NPs (Masse et al, 2019a;Luo, Nguyen et al, 2020) have been developed and widely used in ophthalmic anterior and posterior segment diseases (Figure 1) (Vaneev, Tikhomirova et al, 2021;Wang R et al, 2021) 2.1.1 Organic nanoparticles…”

Light-responsive biomaterials for ocular drug delivery

“…The corneal endothelium is leaky and has no significant effect on molecules penetration that is beneficial to the exchange of nutrients between the corneal stroma and aqueous humor. Importantly, the use of nanomedicine can effectively enhance the corneal permeability of the drug that was reviewed in details in [15][16][17]. The conjunctiva is a mucosa comprised of 2-3 layers of epithelial cells and vascularized connective tissue.…”

“…Drugloaded hydrogel was injected into the eyeballs of mice (orthotopic model of UM), and results demonstrated the superior efficacy of the hydrogel in suppressing tumor growth without causing damage to normal tissue, which could be attributed to synergistic effect of photothermal therapy of AuNRs and Fig. 15 Visualization of the localized surface plasmon resonance of metal nanoparticles-a collective oscillation of valence electrons, in response to an oscillating electric field of light at the resonance frequency. Stimulation of the plasmon by light causes localized heating in the vicinity of the metal nanoparticle.…”