In ophthalmic surgery such as treatment of cataract, corneal transplantation, or vitreous surgery, an intraocular irrigating solution is used to protect the intraocular tissue during the surgery.
An intraocular irrigating solution containing a glutathione derivative has been developed as such an intraocular irrigating solution and has been considered to be a very stable intraocular irrigating solution that effectively suppresses precipitation of calcium (see Patent Literature 1).
Moreover, an intraocular irrigating solution containing a phosphoric diester of ascorbic acid and the tocopherol has also been developed and considered to be excellent in protection of corneal cells and to enable ophthalmic surgery to be safely performed (see Patent Literature 2).
However, cysteine persulfide (CysSSH) as an active sulfur molecule has been reported to be produced in vivo. For example, pyridoxal phosphate (PLP) well known as a coenzyme such as a deaminase has been reported to directly react with cystine to produce CysSSH. Moreover, a cysteine residue in the active center of a certain enzyme, particularly rhodanese known as an enzyme for detoxifying cyan (CN−), has been known to receive a sulfur molecule supplied from a thiosulfate ion to form a persulfide, which reacts with a cyanide ion and subjected to metabolic detoxification into a thiocyanate ion (SCN−).
Commonly, CysSSH had been recognized as an unstable metabolic intermediate responsible for the catalytic activity of such a special enzyme. However, the present inventor found that an active sulfur molecule such as CysSSH in vivo exhibits high antioxidant activity and the function of controlling a redox signal (see Non Patent Literature 1).