(Ph. Eur. 11.6 update)
DEFINITION
Glycerol Eye Drops are a sterile solution of Glycerol in Purified Water.
The eye drops comply with the requirements stated under Eye Preparations and with the following requirements.
Content of glycerol, C3H8O3
95.0 to 105.0% of the stated amount.
IDENTIFICATION
Mix 1 mL of the eye drops with 0.5 mL of nitric acid and superimpose 0.5 mL of potassium dichromate solution. A blue ring develops at the interface of the liquids, which does not diffuse into the lower layer within 10 minutes.
TESTS
Acidity or alkalinity
pH, 4.5 to 7.5, Appendix V L.
ASSAY
Dilute a suitable volume of the eye drops with sufficient water to produce a solution containing 3% w/v of Glycerol. To 5 mL add 150 mL of water and neutralise with 0.1M sodium hydroxide VS, using bromocresol purple solution as indicator. Add 1.6 g of sodium periodate and allow to stand protected from light for 15 minutes. Add 3 mL of propan-1,2-diol, shake, allow to stand protected from light for 5 minutes and titrate with 0.1M sodium hydroxide VS. Each mL of 0.1M sodium hydroxide VS is equivalent to 9.21 mg of C3H8O3
STORAGE
Glycerol Eye Drops should be protected from light.
Strengths available
Eye Drops containing 10, 20, 30 and 50% w/v of glycerol are available.
