(Ph. Eur. 11.6 update)
DEFINITION
Light Liquid Paraffin Eye Drops are Light Liquid Paraffin in a suitable container.
The eye drops comply with the requirements stated under Eye Preparations and with the following requirements.
TESTS
Acidity or alkalinity
To 10 mL add 20 mL of boiling water and shake vigorously for 1 minute. Separate the aqueous layer and filter. To 10 mL of the filtrate, add 0.1 mL of phenolphthalein solution. The solution is colourless. Not more than 0.1 mL of 0.1M sodium hydroxide VS is required to change the colour to pink.
Relative density
0.810 to 0.875, Appendix V G.
Viscosity
25 mPa·s to 80 mPa·s, Appendix V H, Method II.
Solid paraffins
Dry a suitable quantity of the eye drops by heating at 100° for 2 hours and cool in a desiccator over sulfuric acid. Place in a glass tube with an internal diameter of about 25 mm, close the tube and immerse in a bath of iced water. After 4 hours, the liquid is sufficiently clear for a black line, 0.5 mm wide, to be easily seen against a white background held vertically behind the tube.
STORAGE
Light Liquid Paraffin Eye Drops should be protected from light.
