Diquafosol tetrasodium is a P2Y2 receptor agonist that stimulates fluid and mucin secretion on the ocular surface, as a topical treatment of dry eye disease. In Vitro: Cell viability significantly decreased after treatment with 30% diluted diquafosol for 1 hour and 6 hours after treatment with 10% and 20% diluted diquafosol. Twenty-four hours after wounding monolayers, 3% diquafosol, and 0.3% HCECs exhibits significantly more wound healing than the control^[1]. In Vivo: In a rat dry eye model, the P2Y2 agonist diquafosol tetrasodium is found to improve surface health, based on increases in tear fluid secretion, corneal epithelial resistance, and release of glycoprotein-containing moieties from goblet cells. Beginning at 2 weeks and continuing for an additional 2 weeks, maximal declines in dye penetrance of approximately 50% occurred with doses of diquafosol tetrasodium as low as 1%^[2]. INS365 significantly suppresses corneal damage at concentrations of more than 0.1% w/v^[3].