Biphase Serum Formulation and Penetration Enhancers

Thank you for your detailed questions regarding your cosmetic formulations. Let's address each point:

1. Achieving Clean Biphase Separation

It's common to encounter issues with incomplete separation when first formulating biphase serums. The key to achieving the clean, distinct layers seen in commercial products lies in carefully selecting ingredients that are truly immiscible and have a noticeable difference in density.

• Immiscibility: Ensure your oil phase ingredients are completely insoluble in the water phase, and vice versa. Even small amounts of ingredients that act as weak solubilizers or emulsifiers can cause turbidity or incomplete separation.
• Density Difference: The oil and water phases must have different densities for them to separate into distinct layers over time. Typically, the oil phase is less dense and floats on top of the water phase.
• Ingredient Selection: Choose oils (like light esters or silicones) and water-based components (like water, glycols) that are known to separate cleanly. Avoid ingredients that might bridge the two phases.

If your formula isn't separating completely, review all ingredients in both phases to identify any potential culprits that might be causing slight emulsification or turbidity.

2. Using Multiple Penetration Enhancers in Biphase Serum

You asked about using water-soluble Laurocapram and Dimethyl Isosorbide (DMI) in the water phase and oil-soluble Laurocapram in the oil phase of a biphase serum.

While it might seem logical to use different carriers for different phases, the product information for Laurocapram specifically advises against combining it with other carriers, except for 1,2-Hexanediol. The note states that combining Laurocapram with other carriers may reduce the overall efficacy.

Therefore, even though the carriers are in separate phases in a biphase system, combining Laurocapram (both water and oil soluble types) with DMI is not recommended according to the manufacturer's guidance. It is generally better to select one or two compatible penetration enhancers based on the solubility of your key active ingredients.

3. Adding Oil-Soluble Laurocapram to an Oil-in-Water Toner

It's great that you've successfully created an oil-in-water toner using Xanthan Gum and Light Lotion Maker! You're currently using DMI, Butylene Glycol, and water-soluble Laurocapram to enhance penetration, and you're considering adding oil-soluble Laurocapram for oil-soluble actives.

Similar to the biphase serum question, while oil-soluble Laurocapram is designed to enhance the penetration of oil-soluble ingredients, the manufacturer's caution about combining Laurocapram with other carriers (except 1,2-Hexanediol) still applies. Your current formula already contains water-soluble Laurocapram and DMI.

Adding oil-soluble Laurocapram might conflict with the existing carriers, potentially reducing the overall penetration enhancement effect for both water-soluble and oil-soluble actives. To optimize penetration, it's usually best to choose a compatible carrier system rather than combining multiple types that may interfere with each other.

In summary, while your approach to target different phases with specific carriers is conceptually sound, the specific properties and manufacturer recommendations for Laurocapram suggest avoiding its combination with DMI and other carriers (except 1,2-Hexanediol) to ensure optimal performance.