pH drift in Self Tan Formulas
I know that self-tan formulas containing Dihydroxyacetone (DHA) show pH drift over time. But what I noticed is the drift depends upon the type of dosage form. I formulated a lotion, gel, and mousse. All of them had a final pH of 4.25. The pH of lotion and mousse was 4.17 even after a month but pH of gel reduced to 3.95 over night and stabilized around 3.65, which is very low. My worry is drifting of pH lower than 3.50 over time.
What recommendations do you guys have to help self-tan formulas not to drift pH? Also what is a odor blocking technology? Is it just adding more or strong fragrance to the product?