Serum Formulation Advice

Based on the ingredients you've provided, which total 51.9%, here is advice on completing your serum formulation:

1. Adding Distilled Water

Yes, you can use Purified Water to complete the formula to 100%. The remaining 48.1% will primarily be the aqueous phase, which will include the water-soluble ingredients you listed and additional essential components needed for stability and preservation.

2. Missing Essential Ingredients

Your current formula includes active ingredients and some penetration enhancers/moisturizers like Ethoxydiglycol and Phospholipid. However, to create a stable emulsion serum and ensure safety, you are missing several key components:

• Emulsifier(s): To effectively combine the oil phase (Safflower Seed Oil, WhiteCumin™, Dipalmitoyl Hydroxyproline) with the water phase, you will need a dedicated emulsifier system. While Phospholipid has some properties, it's generally not sufficient alone for 10% oil. Consider adding an O/W emulsifier like Sucrose Cream Maker™ or Emulsifying Wax 1000. The usage rate will depend on the specific emulsifier chosen and the total oil percentage, typically ranging from 2-5%.
• Thickener/Rheology Modifier: To give the serum a desirable texture and help stabilize the emulsion by preventing separation, a thickener is needed. A water-soluble thickener like Sepimax Zen can be added to the water phase. The amount needed varies based on desired viscosity, usually between 0.1% and 2%.
• Preservative: Any water-containing product requires a preservative system to prevent microbial contamination. This is critical for product safety and shelf life. A broad-spectrum preservative like Mild Preserved CGZ™ is recommended. Follow the supplier's recommended usage rate, typically 0.5-2%.
• pH Adjuster: The final pH of the serum needs to be adjusted to be skin-compatible and optimal for the stability of your active ingredients (like Azelaic Acid and Niacinamide) and the effectiveness of the preservative. You will need an acidic or basic solution (e.g., Citric Acid or Sodium Hydroxide solution) to adjust the pH to the target range (often between pH 4.0-7.0 for Niacinamide and Azelaic Acid).
• Chelating Agent (Recommended): Adding a chelating agent like Disodium EDTA (typically 0.1-0.2%) can help improve formula stability by neutralizing metal ions that can cause discoloration or degradation.

These additional ingredients would be included within the remaining percentage of your formula, along with the Purified Water.

3. Combining Water and Oil Phases (Emulsification)

To combine the water and oil phases into a stable serum, you need to create an emulsion. This involves:

• Preparing Phases: Create a water phase by combining Purified Water and water-soluble ingredients (Azelaic Acid, Safe-B3™, Seamollient, Ethoxydiglycol, GlucoBright™, thickener, preservative, chelating agent). Create an oil phase with Safflower Seed Oil, WhiteCumin™, Dipalmitoyl Hydroxyproline, and your chosen emulsifier(s). Both phases are often heated to a specific temperature (check emulsifier instructions, typically 70-80°C).
• Emulsification: Slowly add the heated oil phase to the heated water phase while mixing continuously with high shear (using a homogenizer or high-speed mixer) to form the emulsion.
• Cooling and Adding Sensitive Ingredients: Continue mixing while the emulsion cools. Add heat-sensitive ingredients (some actives or preservatives, depending on the type) during the cooling phase below their maximum temperature tolerance.
• pH Adjustment: Once cooled, measure the pH and adjust it to the desired range using a pH adjuster.

Adjusting proportions involves calculating the total percentage of your original ingredients (51.9%) and then allocating the remaining percentage (48.1%) to the Purified Water and the necessary additional components (emulsifier, thickener, preservative, chelating agent, pH adjuster). The specific amounts of the additional components will depend on the chosen ingredients and desired final product characteristics, requiring formulation trials.

Incorporating these steps and additional ingredients will help you create a stable, effective, and safe serum.