Lipid Nanoparticles for Ocular Drug Delivery

Abstract

Despite numerous scientific efforts, efficient ocular drug delivery remains a challenge for pharmaceutical scientists. Delivery of ophthalmic drugs to the targeted ocular tissues is limited by many precorneal, dynamic and static ocular barriers. The anatomy, physiology and biochemistry of the eye render this organ exquisitely impervious to foreign substances. One of the promising strategies nowadays is the use of colloidal carrier systems characterized by a submicron-meter size. Solid lipid nanoparticles (SLN) and nanostructured lipid carriers (NLC) represent promising alternatives to conventional and very popular ocular carrier systems.

Recent Developments of Nanostructures for the Ocular Delivery of Natural Compounds

“…NLCs have been extensively applied for anterior and posterior segment ocular drug delivery via corneal and non-corneal pathways ( Tian et al, 2013 ; Zahir‐Jouzdani et al, 2019 ). The size and surface charge of lipid nanoparticles have an important role in the potential targeting and the extent of drug permeation, in this approach reducing the size of LNPs increases trans-corneal absorption ( Kalam et al, 2010 ) and a positive charge results in higher permeation than a neutral or negative charge and enhances the retention time of nanoparticles on the surface of the cornea ( Tamilvanan and Kumar, 2011 ), however, cationic particles may cause irritation and have toxic effects on ocular tissue due to a greater electrostatic interaction with the anionic layer of ocular tissue thus non-ionic surfactants and lipids preferred ( Naseri et al, 2015 ; Üstündağ Okur et al, 2015 ). Fangueiro et al (2016) evaluated in vivo , ex vivo , and in vitro studies on EGCG loaded cationic lipid nanoparticles (LNPs) produced by the double-emulsion technique.…”