q.s. Deionized water
1% Salicylic Acid
1% Sodium Citrate
20% Propylene Glycol
0,3% Phenoxyethanol (should be water soluble to 0,5%)
0,15% Potassium Sorbate
0,2% Disodium EDTA
3% PEG 40 Hydrogenated Castor Oil
0,1% Tocopherol Acetate
0,3% α-Bisabolol (natural)
- I've made it once with all the ingredients above: precipitation starts in about 5 days;
- I've let out the allantoin: again within 5 days;
- I've let out the whole oil phase (because I can't get the liquid transparant enough) ánd the allantoin: same story...
The formula has a pH of about 3.9-4.2
* What could be the problem here?
* pH 4.2 is a wee bit too high for my liking (I want it between 3.5-4.0), how do I adjust it with the buffer present?