Drug delivery to treate diseases of the eye is not a trivial task - mainly because the tissues provide a very good barrier but also because it is difficult to get enough drug there.
First of all only very small volumes can be administered to the surface of the eye without 'overflowing' and immediate drainage via the tear ducts into the nose/mouth.
Secondly, it is challenging to retain drugs in the eye for sufficient lenghts of time. This is due to the presence of tears and the tear film which together with the blinking action lead to rapid and constant clearance from the eye.
The MET platform was designed to allow facile formulation of hydrophobic drugs for delivery across various biological barrieres. When it comes to topical delivery to the eye MET provides a number of advantage that make it the only safe pentration enhancing technology for use in the eye. Specifically, MET particles easily interact with mucus (as is part of the tear film) and due to their permanent positive charge easily bind to negatively charged cell surfaces. This binding encourages destabilisation of the particles followed by drug release and uptake.