[Bea]

Hello everyone!

Please help me with this preparation:
Finasterid 0,5%
Propylenglykol 10,0%
Hydroxyethylcellulose 1,0%
Ethanol 70% ad 100,0 g

I really tried in countless ways but (I think because of the high concentration of alcohol), the hydroxyethylcellulose doesnt dissolve completely and you can always see some very small clumps (which is simply the Hec that didnt absorb water). I tried to use hot water/cold water, tried to prepare the "alcohol-part" and "water-part" separately and then mix together but nothing worked out!
Please help me, I really need to be able to prepare this for an exam!

[Borek]

Sonication?

[Bea]

Sonication?

It's a pharmacy lab, we dont have that here unfortunately

[billnotgatez]

in addition to using something like a blender or Sonication

will grinding up the hydroxyethylcellulose while dry prior to mixing work  (mortar and pestle )

after mixing are you allowed to filter out the non dissolved pieces.

[della9]

Adjust the order of mixing: Instead of adding HEC directly to the mixture, try adding it gradually while stirring continuously. Start by mixing the Finasterid, propylene glycol, and ethanol together until well combined. Then, slowly sprinkle the HEC into the mixture while stirring vigorously. This method can help prevent clumps from forming.

Pre-hydrate the HEC: Another approach is to pre-hydrate the HEC before adding it to the mixture. Dissolve the HEC in a separate container of water, ensuring that it absorbs and disperses fully. Once the HEC has formed a gel-like consistency, you can gradually add it to the mixture while stirring continuously.

Increase agitation time: If the above methods still result in clumps, try increasing the duration and intensity of the stirring or mixing process. This can help break down the clumps and promote better dispersion of the HEC.

Use a different solvent: If all else fails, consider using a different solvent or combination of solvents that may be more compatible with HEC. You can experiment with alternative solvents such as glycerin or polyethylene glycol (PEG), which are known to have good solubility with HEC.