[Punctal and canalicular plugs: Indications, efficacy and safety (French translation of the article)]. / Les bouchons lacrymaux : indications, efficacité et tolérance.

Lacrimal occlusion with punctal or canalicular plugs have been used to treat dry eye disease for more than 40 years. Indeed, punctal plugs constitute a safe and effective tool to retain the natural tear film and prolong the effect of tear substitutes. A wide variety of plugs is available, differing in their design, location (punctal versus canalicular) and their resorbability. There indications have increasingly broadened, and they are now one of the treatment options for numerous ocular surface diseases. Current research focuses on using punctal plugs for extended delivery of drugs to the ocular surface. This review addresses physiology of lacrimal drainage, available models of punctal plugs, their indications, practical details of prescribing and placing punctal and canalicular plugs, and possible complications.

A new strategy to sustained release of ocular drugs by one-step drug-loaded microcapsule manufacturing in hydrogel punctal plugs.

PURPOSE: To design an injectable hyaluronate (HA)-based hydrogel system that contains drug-loaded microcapsules as resorbable plugs to deliver ocular drugs. METHODS: In-situ drug-loaded, core-shell-structured chitosan (CS)@HA microcapsules were fabricated via HA hydrosol collecting in electrospun bead-rich CS fibers under continuous stirring. An injectable and cytocompatible hydrogel system with different degrees of chemical crosslinking maintained viscoelastic and sustained drug release for a long-term period of time at body temperature in vitro. RESULTS: With the addition of adipic dihydrazide (ADH) or 1-Ethyl-3-(3-dimethyllaminopropyl) carbodiimide hydrochloride (EDCI), HA hydrosols transited from liquid to solid state at the gel point, with the G'/G″ ratio varying between 1.43 and 5.32 as a function of crosslinker concentration in the hydrogel phase. Ofloxacin (OFL) release from the mechanically mixed hydrosol system (CS-HA-A0-E0) and the micro-encapsulated hydrosol formulation (CS@HA-A0-E0) were respectively over 80% and 51% of the total drug load leaching out within 24 h. As for the drug-mixed hydrogel systems with low (CS-HA-A0.06-E0.15) and high (CS-HA-A0.06-E0.30) crosslinking density, the OFL release rate reached 38.5 and 46.6% respectively, while the micro-encapsulated hydrogel systems with low (CS@HA-A0.06-E0.15) and high (CS@HA-A0.6-E0.30) showed only (11.9 ± 2.7)% and (17.4 ± 3.5)% drug release respectively. CONCLUSIONS: A one-step in-situ drug-capsulizing method is developed to fabricate a resorbable hydrogel punctal plug with extended drug release. The chemistry of the crosslinking reaction involves the formation of highly biocompatible HA derivatives. Thus, the hydrogel can be used directly in the tear drainage canalicular system.