Water-in-Oil Emulsifiers for Dry Skin with Urea

For creating a Water-in-Oil (W/O) emulsion suitable for dry skin and incorporating Urea, here are a couple of emulsifier options:

• Water-Capsule™: This is a good option for creating a W/O cream or serum. It is relatively easy to use as it does not require heat during the mixing process and allows for a lower oil percentage (5-20%) compared to traditional W/O emulsions, resulting in a less greasy feel while still providing good skin coating and moisture retention suitable for dry skin. It can create textures from thick-liquid to thick cream.

• Water-in-Oil Max™: This is another effective W/O emulsifier that provides high stability. However, it requires heating the oil phase to 70°C and continuous blending. It also requires a higher oil percentage (19-35%) and the addition of 1% Magnesium Sulfate for optimal stability.

Adding Urea to the Formula

You can incorporate Urea into your W/O formula to enhance its moisturizing properties for dry skin. Both Urea powder and HYDRO-UREA® Liquid are available. Urea is highly effective for dry and dehydrated skin, especially when used at concentrations above 5%. It works well in conjunction with Sodium PCA and Sodium Lactate as they are components of the skin's Natural Moisturizing Factor (NMF).

When using Urea, particularly the powder form, it's important to consider its stability. Urea can break down over time, especially at temperatures above 35°C, causing the pH of the formula to rise. To stabilize Urea and control pH, you can use Gluconolactone (around 15% of the Urea amount) or Triacetin (around 1:10 ratio of Triacetin to Urea).

Consider the characteristics and mixing requirements of each emulsifier to choose the best fit for your formulation needs and desired texture. Remember to stabilize the Urea in your water phase before combining it with the oil phase.