Catechin solubilization by spontaneous hydrogen bonding with poly(ethylene glycol) for dry eye therapeutics.

Catechin exhibits various pharmacological effects, yet its poor aqueous solubility limits its clinical use. Here, we investigate a facile catechin solubilization method via spontaneous hydrogen bonding between catechin and poly(ethylene glycol) (PEG). The method is extremely simple in that mixing PEG with catechin followed by lyophilization completely converts insoluble catechin to soluble PEG/catechin nanoscale complexes. This solubilized catechin formulation is useful for preparing eyedrop medicine, and we demonstrate that the solubilized catechin exhibits therapeutic effect upon dry eye diseases.