Pharmacodynamic properties
Acetylcysteine is a mucolytic and proteolytic agent. N-acetylcysteine is a derivative of the amino acid l-cysteine and inhibits collagenase irreversibly by reducing disulphide bonds and chelating calcium and zinc. It also inhibits matrix metalloproteinase-9 (MMP-9) production by corneal epithelial cells.
Although MMPs play a role in initial corneal wound healing, down-regulation is necessary to prevent corneal digestion and allow corneal wound healing.
The excipient dextran ensures good diffusion and prolonged contact time of the active ingredients.
Pharmacokinetic properties
One study demonstrated, following application of radiolabelled cysteine, that acetylcysteine diffuses at the level of the cornea and the aqueous humor, resulting in intraocular penetration.