Abstract
Topical ophthalmologic treatments have been facing great challenges with main limitations of low drug bioavailability, due to highly integrative defense mechanisms of the eye. This study rationally devised strategies to increase drug bioavailability by increasing ocular surface residence time of drug-loaded nanoliposomes dispersed within thermo-sensitive hydrogels (Pluronic F-127). Alternatively, we utilized sub-conjunctival injections as a depot technique to localize nanoliposomes. Senicapoc was encapsulated and sustainably released from free nanoliposomes and hydrogels formulations in vitro. Residence time increased up to 12-fold (60 min) with 24% hydrogel formulations, as compared to 5 min for free liposomes, which was observed in the eyes of Sprague-Dawley rats using fluorescence measurements. Pharmacokinetic results obtained from flushed tears, also showed that the hydrogels had greater drug retention capabilities to that of topical viscous solutions for up to 60 min. Senicapoc also remained quantifiable within sub-conjunctival tissues for up to 24 h post-injection.
Highlights
Revolutionary approaches to drug delivery systems in the treatment of ocular diseases have rapidly emerged over the past decades
To maintain high patient compliance while achieving therapeutic efficacy, we propose the use of drug-loaded nanoliposomes dispersed within thermo-sensitive hydrogels (Pluronic F-127), via a topically applicable hydrogel formulation or a minimally invasive sub-conjunctival injection to increase the residence time and bioavailability of ocular therapeutics
It was observed that 20 mM Senicapoc-loaded DPPC liposomes had no significant changes in its size with an average of 91.3 ± 1.2 nm (Figure 2) over a period of 28 days as compared to the initial fabricated size of 90.0 ± 0.5 nm (n = 3)
Summary
Revolutionary approaches to drug delivery systems in the treatment of ocular diseases have rapidly emerged over the past decades. The treatment of ocular surface disease relies on topical administration of drugs. Less than 5% of topically administered drugs reach the anterior segment and an even smaller fraction reaches the posterior chamber [1]. This suggests that dynamic clearance of drugs occurs primarily via tears or at the ocular surface. Treatment of ocular surface diseases have faced many challenges over the decades either due to poor treatment efficacies of topical eye drops or poor acceptability of the patients due to more invasive routes of administration [1,2,3]. Other common problems include drug spiking dosages and efficacy crashes [1]
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