I'm making deodorant cream (O/W emulsion) for myself with alum (potassium aluminum sulphate) as active. Personally, I don't have problems with the low pH (approx. 2.5-3.0).
For as far as I know alum is unstable under higher pH conditions.
1. Would it be ok for the alum stability to raise the pH a little, to pH 3.5-4.0 (with NaOH)?
2. Preservatives might not be necessary at these conditions, but I like to be on the safe side. Would Phenonip at about 0,5% be a good idea at this pH?
3. I'm not sure if the emulsifiers I have can handle that low a pH.
Which one would be suitable:
- GMS + PEG 100 stearate
- Polyglyceryl-3 stearate
- Glyceryl stearate citrate
- GMS + Ceteareth 20
- Polyglyceryl-6 Stearate (and) Polyglyceryl-6 Behenate (Tegocare PBS 6)
Thanks in advance! :-)