Abstract
Purpose :
Glaucoma is an optical neuropathy affecting over 67 million people in the world. Efficiency of current active molecules, as travoprost (hydrophobic) and timolol maleate (hydrophilic), is limited when administered by ophthalmic drops. Indeed, more than 99.9 % is discarded due to multiple factors including lacrimal drainage. Low retention time of drugs at the cornea leads to their poor penetration. The aim of the project is to develop a drug delivery system allowing the drug penetration through biological barriers. Our hypothesis is that a drug delivery system based on gold nanoparticles should enhance the efficiency of the drugs. The main objective is to study the encapsulation ability of gold nanoparticles towards the hydrophobic/hydrophilic properties of the drugs. The specific objectives are 1) the synthesis and characterizations of gold nanoparticles, 2) the establishment of the encapsulation protocol, 3) the development of the separation method of free and encapsulated drugs and 4) the quantification of the encapsulated drugs.
Methods :
Ultrastable gold nanoparticles were synthesized by a new method. An encapsulation protocol was settled in aqueous conditions at 37°C. The separation of free and encapsulated drugs was performed with magnetic beads. The quantification of the encapsulated drugs was then performed by high performance liquid chromatography and confirmed by UV-visible spectroscopy.
Results :
Gold nanoparticles of (28 ± 1) nm were synthesized and purified according to our new experimental conditions. These ultrastable gold nanoparticles support harsh conditions as several cycles of freeze drying and heating (Fig. 1). The encapsulation protocol differs depending on the hydrophobic/hydrophilic properties of drugs. The separation method involving magnetic beads was optimized to get rid of non-specific interactions (Fig. 2). The encapsulation efficiency was higher with hydrophobic drugs than with hydrophilic ones.
Conclusions :
Our ultrastable gold nanoparticles can have a major impact in nanomedicine. We showed that active molecules used for glaucoma therapy, as timolol maleate and travoprost, can be encapsulated in gold nanoparticles. Further analysis will allow identifying the encapsulation properties of various gold nanoparticles, differing by their size, shape and chemical surface. These data suggest the possible improvements in glaucoma therapy thanks to gold nanoparticles.
This is an abstract that was submitted for the 2018 ARVO Annual Meeting, held in Honolulu, Hawaii, April 29 - May 3, 2018.