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Question

Posted on: March 6 2013

Problem with an ointment for treating pigment stains:

Hydroquinone 4%
hydrocortisone acet 1%
Tretinoine 0.05%
Alkohol 96 16%
Hypromellose 4000mPas 16.8%
White Vaseline AD 100% < br/> Notes:
  1. Why hypromellose in preparation?
  2. after metabisulfite 0.1% or Vit C 0.1% add?
  3. is alcohol needed?
When Hydroquinone and Tretinoine are dissolved in alcohol and hypromellose with part of this solution is rubbed then we fix a pastry.

Answer

Personally, I find the choice of excipient peculiar. I do not understand well why the doctor does not use a cream base. When you consult the booklet Galensich Formularium you will find the used ointment base under the pastes for oromucosal use!

The biscuits that you determine is due to the incompatibility of HPMC with non-water-diluted alcohol. The solution, which is closest to the original formula, is the replacement of HPMC by Hydroypropylcellulose high viscosity. Both Antioxydantia, which you mention, are for aqueous solutions. Here I would add 0.1% Butylhydroxytolua. This is an antioxydance for fats or oils.