W/O Cream Base Formulation Issue: Separation with Mineral Oil
Question
I want to create a W/O formulation using:
- Mineral Oil (Paraffinum Liquidum) 35%
- Liquid Germall Plus 1%
- DI Water 62%
- Water in Oil EZ 2% (initially, adjusted up to maximum %)
- Magnesium Sulfate (also tried)
I have tried adjusting the oil percentage (increasing/decreasing) and increasing the percentage of Water in Oil EZ to its maximum, and also used Magnesium Sulfate, but the formulation still separates.
I need a water-in-oil emulsifier that prevents separation with Mineral Oil. What emulsifier do you recommend, and what is the recommended usage percentage?
*Note: I do not need to include other active ingredients as this is intended only as a W/O cream base for research purposes.
Answer
Based on your previous attempts and the challenges you've faced, it seems the Water in Oil EZ and Magnesium Sulfate combination wasn't sufficient to create a stable W/O emulsion with 35% Mineral Oil. Mineral oil can sometimes be challenging to emulsify stably in W/O systems depending on the emulsifier chemistry.
While the recent product searches did not yield specific W/O emulsifiers suitable for direct recommendation from our database, I can provide general guidance on types of W/O emulsifiers that are commonly used and effective with mineral oil, along with typical usage percentages.
Commonly used W/O emulsifiers that provide good stability, especially with mineral oil, include:
- Silicone-based emulsifiers: Ingredients like Cetyl PEG/PPG-10/1 Dimethicone or Lauryl PEG/PPG-18/18 Methicone are very effective W/O emulsifiers that can handle high oil loads and provide excellent stability and a pleasant skin feel.
- Typical Usage: These are often used at concentrations between 1% and 3%.
- Polyglyceryl-based emulsifiers: Combinations such as Polyglyceryl-4 Isostearate, Cetyl PEG/PPG-10/1 Dimethicone, and Hexyl Laurate are also effective W/O systems.
- Typical Usage: The blend is typically used at 2-5%.
When formulating a W/O emulsion, besides choosing the right emulsifier, the manufacturing process is crucial. You typically need to add the water phase very slowly to the oil phase (containing the emulsifier) while mixing with high shear.
The separation you experienced could be due to:
- Incompatibility between the specific emulsifier (Water in Oil EZ) and Mineral Oil at that concentration.
- Insufficient emulsifier concentration for the amount of oil and water phases.
- Lack of a stabilizing co-emulsifier or thickener in the water phase (though you mentioned trying Magnesium Sulfate, which acts as an electrolyte stabilizer, it might not have been enough or the right type).
- Insufficient mixing energy or incorrect addition method during preparation.
For your research base cream, I recommend looking for emulsifiers from the chemical groups mentioned above. You would typically start with the recommended usage percentage provided by the supplier of the specific emulsifier you choose and adjust based on your formulation's stability.
Unfortunately, I cannot recommend specific products from our database based on the recent searches. You may need to explore other W/O emulsifier options available to you that fall under the chemical types known to work well with mineral oil.