Cetyl Alcohol Solidification and L-Ascorbic Acid Stability in Cream Formulation

Based on the conversation, the issue with Cetyl Alcohol solidifying into flakes after being melted with oil and added to the cream base is likely due to the low percentage of oil in your formula (2% Fractionated Coconut Oil vs 5% Cetyl Alcohol) which is insufficient to keep the wax dissolved upon cooling. The processing method, particularly the temperature and mixing speed during the emulsification phase, is also crucial.

The staff also advised on the stability of L-ascorbic acid (Vitamin C) in your original formula. They indicated that it would likely be unstable due to the high heat required to melt waxes (which can degrade L-ascorbic acid) and the presence of Triethanolamine (TEA), which raises the pH. L-ascorbic acid requires a low pH (3.0-3.5) for stability.

To address these issues, the staff proposed a revised formula and detailed procedure:

Revised Formula:

• Phase A (Water Phase): Water (remaining %), EDTA 0.05%, Aloe Vera Extract 3%, Pueraria Mirifica 5%, L-ascorbic acid 15%
• Phase B: Ferulic Acid 0.5%, Ethoxydiglycol 3%
• Phase C: Rich Cream Maker 4%, Vitamin E 1%
• Phase D (Oil/Wax Phase): Fractionated Coconut Oil 2%, Cetyl Alcohol 2%
• Phase E (Preservative): Phenoxyethanol 1%

Revised Procedure:

1. Mix Phase A until clear. Set aside.
2. Mix Phase B until clear. Set aside.
3. Mix Phase C together.
4. Gently heat Phases A, B, and C to 45-50°C. Then, combine and mix all three phases until a cream forms. Set aside.
5. Heat Phase D until it is completely melted into a clear oil (very hot).
6. While the cream from step 4 is still warm, mix it at high speed (at least 1000 rpm). Slowly pour the hot liquid Phase D into the cream while mixing.
7. Add Phase E (Phenoxyethanol) to the cream and mix until incorporated.

The staff also noted that the total oil phase (Phase D) should ideally be around 5-7% of the formula (not exceeding 10%) for stability and proper texture. While the revised formula still uses Cetyl Alcohol, the adjusted percentages and procedure are intended to help achieve a stable cream.