Formulation Review: Skin Brightening Cream

This formulation includes several effective ingredients for skin brightening and reducing melasma, such as Activated Resorcinol, Vitamin B3, N-Acetyl Glucosamine, Azelaic Acid, and Tranexamic Acid. The combination of these actives targets pigmentation through different mechanisms.

Ingredient Compatibility:

• Activated Resorcinol is compatible with Vitamin B3 and N-Acetyl Glucosamine.
• LipidSoft acts as an emollient (oil phase) and is where oil-soluble ingredients like Activated Resorcinol should be dissolved.
• Light Cream Maker is an effective emulsifier for creating a cream base without heat.

Key Considerations for Stability and Efficacy:

• pH Level: The optimal pH range for Activated Resorcinol is 4.5-5.5. Vitamin B3 is also stable in this range. Azelaic Acid and Tranexamic Acid are acidic ingredients, and their inclusion will lower the formula's pH. It is crucial to measure and adjust the final pH of the cream to be within the 4.5-6 range, ideally 4.5-5.5, for optimal performance and stability of the active ingredients.
• Electrolyte Sensitivity: Light Cream Maker can be sensitive to high concentrations of electrolytes, which include ingredients like Azelaic Acid and potentially others depending on their form. Adding all electrolyte-containing ingredients at once, as described in step A being added to B, might cause the cream to thin or affect stability. A method of gradually adding the dissolved acidic/electrolyte ingredients to the formed cream base while stirring and observing the viscosity might be beneficial.
• Preservation: As noted in the previous reply, adding a suitable preservative is essential to prevent microbial growth in the cream.
• Activated Resorcinol Stability: Activated Resorcinol is light-sensitive and can discolor. Packaging the final product in an opaque container is recommended. Adding Disodium EDTA (typically 0.2%) to the formula can also help prevent discoloration.

Mixing Method Evaluation:

The proposed mixing method is generally logical by separating water and oil phases. However, combining all water-soluble actives and acids (electrolytes) in step A and adding them all at once to the emulsified oil phase (B) might challenge the Light Cream Maker's ability to maintain viscosity, especially with 5% Azelaic Acid and 3% Tranexamic Acid. Gradually adding the dissolved acidic/electrolyte ingredients after the initial cream has formed could lead to a more stable texture.

Overall, the formulation has good potential for its intended purpose. Paying close attention to pH adjustment and potentially adjusting the mixing method for electrolyte incorporation will be key to achieving a stable and effective product. Remember to add a preservative.