Resveratrol and lipoic acid: A promising combination for treating dry eye disease

The purpose of this study was to develop an ophthalmic preparation (LA/Res/HP-beta-CD) containing alpha-lipoic acid (LA) and resveratrol (Res)/hydroxypropyl-beta-cyclodextrin (HP-beta-CD) inclusion complex and to investigate the effect of LA/Res/HP-beta-CD on medicating the dry eye disease. The inclusion complex of Res/HP-beta-CD was prepared by solvent evaporation method to solve the poor water-solubility of Res, and the optimal proportion of resveratrol and lipoic acid in formulation was screened by hydroxyl radical scavenging test in vitro. Comparing with Res/HP-beta-CD, the preparations of LA/Res/HP-beta-CD had longer t1/2 and larger AUC in tears, had more advantages in increasing Res concentration in cornea, conjunctiva and sclera, improving tear secretion and tear film stability, repairing the corneal epithelial and conjunctiva injury, improving mucin and inorganic salt components of tears, reducing pro-inflammatory factor IL-1 beta in the cornea, enhancing Vitamin D level of eyes. These results showed that LA improved the therapeutic effect of Res, and the combined preparations would exhibit a potential application prospect in treating dry eye disease.