Patent ID: 8372434

Claim:
An ophthalmic oil-in-water submicron emulsion, which comprises colloid particles having an oily core surrounded by an interfacial film, said emulsion comprising: 1% by weight of mineral oil; 0.002% by weight of at least one cationic agent, said agent being cetalkonium halide; 0.3% by weight of tyloxapol; and 0.1% by weight of poloxamer, wherein, said emulsion does not contain phospholipids, said emulsion does not contain anionic surfactants, said emulsion has a positive zeta potential, and said emulsion meets the zeta potential stability under thermal stress conditions as determined by Test A: measuring zeta potential, in mV, of said emulsion at the time of preparation is Z 0 , sealing 5-10 ml of said emulsion in 10 ml Type I glass vials under nitrogen atmosphere without bubbling, storing said sealed vials at 80° C. for 15 hours, measuring zeta potential, in mV, of said emulsion at 15 hours, Z 15 , determining the difference between Z 15h −Z 0 , δA, wherein, the emulsion meets the zeta potential stability under thermal stress conditions according to Test A for a δA less than the standard error of zeta potential measurement.