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Question

Posted on: March 6 2013

Problem with Carbomeergel: Tetracaine HCl 4% groundnut oil span 80 Tween 80 Carbomer ad 50g

I have I mixed tetracaine on the plate with glycerin (due to good solubility of tetracaine according to Martindale) or with propylene glycol (constituent of carbomeergel) but when mingling with the Carbomeergel, it diluted completely.
when I mix the tetracaine in a mortar with the oil. Ok! Then I have Tween and Span attached. Ok! Then I attached the Carbomeergel with the same result: a completely diluted gel.

Answer

In The Galenic formulary is a hydroxyethylcellulose gel described, use that instead of the Carbomeergel.