Advances in Nanogels for Topical Drug Delivery in Ocular Diseases

Abstract

Nanotechnology has accelerated the development of the pharmaceutical and medical technology fields, and nanogels for ocular applications have proven to be a promising therapeutic strategy. Traditional ocular preparations are restricted by the anatomical and physiological barriers of the eye, resulting in a short retention time and low drug bioavailability, which is a significant challenge for physicians, patients, and pharmacists. Nanogels, however, have the ability to encapsulate drugs within three-dimensional crosslinked polymeric networks and, through specific structural designs and distinct methods of preparation, achieve the controlled and sustained delivery of loaded drugs, increasing patient compliance and therapeutic efficiency. In addition, nanogels have higher drug-loading capacity and biocompatibility than other nanocarriers. In this review, the main focus is on the applications of nanogels for ocular diseases, whose preparations and stimuli-responsive behaviors are briefly described. The current comprehension of topical drug delivery will be improved by focusing on the advances of nanogels in typical ocular diseases, including glaucoma, cataracts, dry eye syndrome, and bacterial keratitis, as well as related drug-loaded contact lenses and natural active substances.

Recent Advances in Nanotechnology for the Treatment of Dry Eye Disease

“…Nanogels [109] Three-dimensional crosslinked polymeric network. Categorized based on the type of bonds in the polymer network (non-covalent, covalent).…”

“…These nanogels are easy to prepare; however, they are fragile and unstable due to the low binding energy. Conversely, chemically crosslinked nanogels are made of covalent bonds that allow a higher stability, but they have a higher toxicity risk due to crosslinking agent residues after preparation [ 109 ].…”

A recent overview of surfactant–drug interactions and their importance

“… 105 Nanotechnology-based carriers' capacity to entrap both hydrophilic and lipophilic medicines, improve ocular permeability, prolong residence duration, enhance drug stability, and increase bioavailability is the reason for their development. 106 The consequences of the built-in nanocarriers can be predicted using a variety of in vitro , ex vivo , and in vivo characterization techniques. 107 In terms of analytical means, mathematical models are being employed for theoretical analysis, which is a crucial gateway to elucidate the interactions present in the mixed systems of poorly soluble medicines and surface-active agents and identify the novel physical features.…”

Review on nanogels and their applications on dermal therapy

“…165 Nanogels from different polymers have been and continues to be studied for application in different ocular diseases. 166 Nanogels are also investigated for central nervous system, these gels containing therapeutic T lymphocytes for localized delivery to glioblastoma cells for brain tumor immunotherapy were developed using poly (ethylene glycol)-g-chitosan They showed greater efficacy in killing glioblastoma cells compared with the Matrigel control. 167 However, one of the challenges faced by the nanogels in central nervous system application is passing through the blood–brain barrier which means that the shape, size and structure of a nanogel will have a huge impact in the development of their central nervous system application.…”