The below is a simple emulsion. What should the HLB that you would want based on the below oils, What type of ingredient would you put in the xxxxxxxx row and why? Water Carbomer Qs 0.2% Glycerine 2% Jojoba Oil 10% Bees Wax 4% Cetyl Alcohol 2% Mineral Oil 4% Petrolatum 4% Emulsifier 5% XxxxxxxxxxXXXXXXXXXXXXXXX 3% Phenoxyethanol 0.8%
The Correct Answer and Explanation is:
To determine the correct HLB (Hydrophilic-Lipophilic Balance) and the ingredient that should go in the “xxxxxxxx” row of this formulation, we need to consider both the HLB requirements and the role of the ingredient within the emulsion system.
HLB and Emulsifiers
The HLB is a measure of the balance between the hydrophilic (water-loving) and lipophilic (oil-loving) parts of a molecule, which is crucial in selecting an appropriate emulsifier. Generally, emulsifiers with an HLB between 8-16 are used for forming oil-in-water emulsions, while those with an HLB between 3-6 are typically used for water-in-oil emulsions.
Analyzing the Ingredients
Here’s a breakdown of the oil- and water-soluble components of the formulation:
- Water and Glycerine (water-soluble, hydrophilic)
- Carbomer (water-soluble, often used as a thickening agent)
- Jojoba Oil, Mineral Oil, Petrolatum (oil-soluble, lipophilic)
- Beeswax, Cetyl Alcohol (lipophilic but with some emulsifying properties)
- Emulsifier (typically an agent to stabilize the emulsion)
Given this composition, the formulation seems to aim for a water-in-oil emulsion since it includes a significant amount of lipophilic substances like oils, waxes, and petrolatum. To form a stable water-in-oil emulsion, you would likely need an HLB range of 4-6 for the emulsifier.
The “xxxxxxxx” Ingredient
Now, looking at the “xxxxxxxx” row, which holds 3% of the formulation, the ingredient in this row needs to complement the emulsifier. Since the formulation is water-in-oil, the ingredient should enhance the emulsion stability or contribute to skin feel and texture.
A good option for this row could be Stearic Acid or Cetearyl Alcohol. These are fatty alcohols, which can help with the thickening of the formulation, contribute to the emulsification process, and improve the texture. Both ingredients are lipophilic and would fit well with the overall oil phase. Cetearyl Alcohol, in particular, can have emulsifying properties, stabilizing the formulation.
Why This Ingredient
- Stearic Acid/Cetearyl Alcohol are common in emulsions to enhance the stability of the oil phase and add to the emulsion’s viscosity.
- These ingredients would help to improve the skin feel and texture, making the formulation smoother and easier to apply.
In conclusion, based on the oil-heavy formulation and the desired water-in-oil emulsion, an HLB of around 4-6 would be ideal, and Stearic Acid or Cetearyl Alcohol would be suitable for the “xxxxxxxx” row.
