(Open access funding provided by Semmelweis University)
Subjects:
Ophthalmology
Ascorbic acid (AA) has a pivotal role in corneal wound healing via stimulating the
biosynthesis of highly organized extracellular matrix components, but its rapid degradation
and low corneal permeability limits its therapeutic effects. In this paper, we present
the pharmacokinetic properties of a liposomal-based formulation of AA in terms of
corneal permeation. Chemical stability, shelf-life, and drug release rate of lyophilized
liposome (AA-LLipo) formulation was determined in comparison to free-form of AA solution
using high-performance liquid chromatography (HPLC) and rapid equilibrium dialysis.
In vitro transcorneal permeability was studied using a parallel artificial membrane
permeability assay (PAMPA). Ex vivo permeation was examined on AA-LLipo-treated porcine
cornea by determining the AA content on the ocular surface, in the cornea as well
as in the aqueous humor using HPLC, and by Raman-mapping visualizing the AA-distribution.
Our results showed that the liposomal formulation improved the chemical stability
of AA, while drug release was observed with the same kinetic efficiency as from the
free-form of AA solution. Both corneal-PAMPA and porcine corneal permeability studies
showed that AA-LLipo markedly improved the corneal absorption kinetics of AA, thus,
increasing the AA content in the cornea and aqueous humor. AA-LLipo formulation could
potentially increase the bioavailability of AA in corneal tissues.
