BP 2025 (Ph. Eur. 11.6 update)
Action and use
Stabilizer in pharmaceutical products.
DEFINITION
Carbomer Eye Drops are a sterile viscous solution of Carbomer 940 or Carbomer 980 in Purified Water.
The eye drops comply with the requirements stated under Eye Preparations and with the following requirements.
IDENTIFICATION
A. Add 15 g of the eye drops to 85 mL of water and mix thoroughly. To 3 mL add 1 mL of calcium chloride solution, a fine white precipitate is produced.
B. Add 0.5 mL of thymol blue solution to 10 g of the eye drops. A yellow colour is produced. Add 0.5 mL of cresol red solution to 10 g of the eye drops. A yellow colour is produced.
TESTS
Acidity or alkalinity
pH, 6.6 to 7.1, Appendix V L.
Apparent viscosity
75 to 125% of the declared value when determined by the following method. Empty the contents of sufficient containers to obtain 200 g of the eye drops, taking care to avoid incorporation of air bubbles, and homogenise. Allow to stand at 25° for 60 minutes. Immerse the appropriate spindle of a rotational viscometer, switch on after 5 minutes and determine the viscosity at 25°, Appendix V H, Method III, using a shear speed of 5 per second.
Clarity of solution
The eye drops are not more opalescent than reference suspension III, Appendix IV A.
LABELLING
The label states the nominal viscosity in millipascal seconds.
