How to make a mitomycin 0.02% collyrium without preservative?

You must begin to reconstitute the injectable solution by 20 ml 0.9% NaCl. From this solution you take 2 ml and lengt further to 10 ml with 0.9% NaCl solution. This solution is sterile filtered on membrane filter 0.2 μm in a sterile zentrop vial. The solution must be stored in the refrigerator. The solution has a loss of 2% in 14 days at 5 °C, so that a shelf life of 1 month is in the possibilities.