Improving Absorption and Maintaining Structure in Herbal Cream Base
Question
I am developing a herbal cream base and previously switched emulsifier systems (to Sucro Plus) to resolve a "krap khao mak" (fermented rice residue) issue, aiming for better coating. The current base formulation is:
- Mineral Oil: 10%
- Stearyl alcohol: 5%
- Pentaeryl distearate: 5%
- Sucro plus: 2%
- Propylene glycol: 5%
- Water: QS
I am now facing two new problems with this base:
- The absorption is still too slow and the texture feels heavy.
- When I attempted to reduce Stearyl alcohol and Pentaerythritol distearate to improve absorption, the resulting cream became liquid and lost its set/structure.
I request advice on how to adjust this formulation to improve absorption while maintaining the necessary viscosity and structure.
Answer
Analysis and Formulation Adjustment Guidance
The main issues with your current formula are poor absorption/heavy feel and loss of structure when reducing the solid structurants (Stearyl Alcohol and Pentaerythritol Distearate).
Your current formula contains a high percentage of heavy oil (Mineral Oil) and solid waxes (Structurants), which are the primary causes of both problems.
Solution 1: Addressing the Heavy/Greasy Feel (Poor Absorption)
The heavy feel comes from 10% Mineral Oil combined with 10% solid waxes (Stearyl Alcohol + Pentaerythritol Distearate).
Recommendations for Adjustment:
Reduce Mineral Oil:
- Decrease Mineral Oil from 10% to 5-7%.
- Replace with Lighter Emollients: Substitute the reduced amount with a fast-spreading, light-feeling emollient such as Caprylic/Capric Triglyceride or Isopropyl Myristate (IPM). This improves spreadability and reduces the heavy, occlusive feel.
Adjust Structurant Balance:
- While Stearyl Alcohol and Pentaerythritol Distearate are necessary for structure, a combined 10% might be too high for a light-feeling cream.
Solution 2: Addressing Loss of Structure (Liquefaction)
The cream becomes liquid when Stearyl Alcohol and Pentaerythritol Distearate are reduced, indicating that the cream's structure relies heavily on these oil-phase structurants.
Recommendations for Adjustment:
Maintain a Minimum Structurant Level:
- Keep the total level of Stearyl Alcohol and Pentaerythritol Distearate at approximately 6-8% to ensure good emulsion stability.
- Test Ratio Adjustments: For example, Stearyl Alcohol 3% + Pentaerythritol Distearate 3% (6% total).
Introduce an Aqueous Phase Thickener (Hydrocolloid):
- This is the most critical step. Adding a water-phase thickener provides viscosity and structure in the water phase, allowing you to reduce the heavy oil-phase waxes while maintaining the desired consistency.
- Examples:
- Xanthan Gum: Use at 0.2% - 0.5%.
- Carbomer: Use at 0.1% - 0.3% (requires neutralization with a base like Triethanolamine (TEA)).
Summary of Suggested Formula Adjustment (Example)
| Component | Original Formula (%) | Adjusted Formula (Example) (%) | Role/Reason for Adjustment |
|---|---|---|---|
| Mineral Oil | 10 | 5 | Reduce heaviness/greasiness. |
| Light Emollient (e.g., Caprylic/Capric Triglyceride) | 0 | 5 | Replaces Mineral Oil to improve absorption. |
| Stearyl Alcohol | 5 | 3 | Reduce heaviness/waxiness. |
| Pentaerythritol Distearate | 5 | 3 | Reduce heaviness/waxiness. |
| Sucro Plus | 2 | 2 | Primary Emulsifier (Maintain). |
| Propylene Glycol | 5 | 5 | Humectant (Maintain). |
| Xanthan Gum (or Carbomer) | 0 | 0.3 | Adds aqueous phase viscosity to maintain structure when waxes are reduced. |
| Water | 73 | 76.7 | QS to 100%. |
What I need from you to confirm
To provide more precise advice, please provide the following information:
- What specific herbal extracts are you using? (Type and percentage).
- What grade of Sucro Plus are you using? (e.g., Sucrose Polystearate or Sucrose Stearate) to confirm the emulsion system (O/W or W/O).
Follow-up Replies
Question:
I am formulating an emulsion using Sucrose Cream Maker™ (Emulgade Sucro plus) and Xanthan Gum as a thickener, and I do not have a homogenizer.
My current formulation structure includes solid waxes (Stearyl Alcohol and Pentaerythritol Distearate).
My question is:
Can I completely replace ALL of the solid waxes in the formula with Caprylic/Capric Triglyceride (CCT)? If I make this replacement, will the resulting emulsion remain stable and prevent separation, considering the use of Xanthan Gum and Sucro Plus without high-shear mixing?
Answer:
Analysis of Your Emulsifier and New Question
The emulsifier you are using, Sucrose Cream Maker™ (e.q. Emulgade Sucro Plus) (Product ID 35082), is an excellent non-ionic O/W emulsifier (Sucrose Stearate/Polystearate). It is known for creating stable, mild, and light-feeling emulsions, often without requiring high shear (homogenizer).
Answer to Your New Question: Replacing All Wax with Caprylic/Capric Triglyceride (CCT)
No, it is highly recommended NOT to replace ALL of the solid waxes (Stearyl Alcohol and Pentaerythritol Distearate) with Caprylic/Capric Triglyceride (CCT).
Reasons:
- Loss of Structure: CCT is a liquid oil and provides no structure or viscosity. While Xanthan Gum thickens the water phase, it cannot fully compensate for the loss of the crystalline network provided by the waxes in the oil phase.
- Emulsion Instability (Without Homogenizer): The solid waxes (Stearyl Alcohol, Pentaerythritol Distearate) act as co-emulsifiers and structurants, helping to stabilize the oil droplets, especially when using a low-shear method (no homogenizer). Removing them completely, even with Sucrose Cream Maker™ and Xanthan Gum, significantly increases the risk of long-term separation (creaming or breaking).
- Texture: The resulting product will likely be a very thin milk or lotion, not a cream, which may not meet your desired texture profile.
Recommended Strategy: Reduction, Not Elimination
To achieve better absorption while maintaining structure, you must reduce the waxes and compensate with a water-phase thickener.
Revised Recommended Formula Structure:
| Component | Original (%) | Recommended Range (%) | Role/Reason for Adjustment |
|---|---|---|---|
| Mineral Oil | 10 | 5 - 7 | Reduce heaviness. |
| Light Emollient (e.g., Caprylic/Capric Triglyceride) | 0 | 3 - 5 | Replaces heavy oil to improve spreadability. |
| Stearyl Alcohol | 5 | 2 - 3 | Reduce, but maintain for structure. |
| Pentaerythritol Distearate | 5 | 1 - 2 | Reduce, but maintain for structure. |
| Sucro Plus (Sucrose Cream Maker™) | 2 | 2 | Emulsifier (Maintain). |
| Propylene Glycol | 5 | 5 | Humectant (Maintain). |
| Xanthan Gum | 0 | 0.2 - 0.5 | CRITICAL: Provides water-phase viscosity to compensate for reduced waxes. |
| Water | QS | QS | QS to 100%. |
Key Takeaway: Start with a total wax/structurant level (Stearyl Alcohol + Pentaerythritol Distearate) of 3% to 5% and add 0.3% Xanthan Gum. This balance will significantly lighten the feel while preserving the cream structure.
Regarding Herbal Extracts
Since you plan to add herbal extracts later, remember that:
- Water-Soluble Extracts: Will replace part of the water (QS).
- Oil-Soluble Extracts: Will replace part of the oil phase (Mineral Oil or CCT).
Always adjust the water or oil phase downwards to accommodate the extract percentage to keep the total formula at 100%. The structural components (waxes, emulsifier, Xanthan Gum) should be kept constant to maintain stability.
