• Formulating

  Viscosity problem

  Posted by Larissa9 on September 19, 2020 at 5:51 pm

  Hello everybody,
  I am on my final year of Pharmacy college (read: no experience) and working on a gel with glycolic acid and suspended olive pit particles that are suposed to work as mechanical body peeling. When I make this gel everything looks great for maybe two weeks then olive pits start to sediment. I chose a pH of 3 and currently considering to make it 3,5.
  This is what I have now;

  Aqua purificata 79,56%
  Glycolic acid (70%) 5,72%
  NaOH 0,42%
  Hypromellose 2%
  Xanthan gum 1%
  Olive pit particels (500, Fagron) 1,2%
  Cocamidopropyl betaine 9%
  Vitis viniferae 0,4%
  Aurantii aeth 0,7% 

  How do you think I can stop sedimentation?
  Thank you very much for your help.

  Larissa9 replied 4 years, 3 months ago 2 Members · 2 Replies

  • viscosity
• 2 Replies

• 

  Pharma

  Member

  September 19, 2020 at 6:45 pm

  If sedimentation is caused by a progressive viscosity loss, raising pH might be the solution. pH 3 is the lower end of stability for both polymers and I’d guess it’s hydrolysis of these which would be responsible for said viscosity loss.

• 

  Larissa9

  Member

  September 19, 2020 at 7:14 pm

  Thank you for your suggestion, makes sense.
  I will try with pH 3,6 which is also the pKa of glycolic acid and see what happens.

Log In to Reply