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Question

Posted on: March 6 2013

Like a practical solution for the preparation of fluphenamic acid 3% gel.

The solution found in the book CARBOMEREN is not going. We have already tried several possibilities, but after adding water to the solution of fluphenamic acid in PEG400 or a mixture PEG/propylene glycol/isopropyl alcohol we always get a yellow precipitation.

Answer

Following a series of experiments and reactions from fellow & #039; s, the next method is proposed:

  1. In a tarred recipient (tare weight), 3.0 g of fluphenamic acid is feared with 2.0 g of Carbopol 980 powder after which the mixture is homogenous Moistened with 30 g isopropyl alcohol and then with 10g propylene glycol and 15g PEG 400.
  2. mix until an approximately even gel is obtained.
  3. fill with isopropanol to the correct weight (tare + 60g); any precipitation should be avoided!
  4. then add 40.0 G 2% Carbopolgel FN VI in three parts (20g + 10g + 10g) under blending. When adding the last 10 g of gel we sometimes get precipitation again. This is due to loss of isopropyl alcohol by evaporation.
  5. therefore the recipient on the end weigh and add isopropanol to "100g + tare weight". The fluphenamic acid goes back into solution and the gel is now again translucent. Immediately pack the gel into a tube to prevent evaporation of isopropanol.