Adding Active Ingredients to Cream Base: Water Amount and Solubility

Regarding the amount of water for pre-dissolving:

The staff's suggestion to pre-dissolve the powders (Alpha Arbutin, Zinc PCA) and mix with the liquids (Nanowhite, Licorice Extract) in a small amount of water is to help them disperse and incorporate more easily into the cream base.

You should use just enough water to fully dissolve the powders and create a smooth, liquid mixture when combined with the other liquid additives. There isn't a strict percentage relative to the cream, as it depends on the total amount of additives you are incorporating.

A practical approach is to use an amount of water roughly equal to the total weight or volume of the powders and liquids you are adding, or slightly more if needed to ensure everything dissolves and mixes completely into a fluid state before adding this concentrated mix to your cream. The key is to keep this pre-mix volume small relative to your main cream batch.

Regarding adding water-soluble and oil-soluble extracts to your cream base:

Based on the ingredient list you provided for your existing cream (which contains both water-based ingredients like Aqua, Butylene Glycol, etc., and oil/silicone-based ingredients like Cyclopentasiloxane, Isononyl Isononanoate, oils, triglycerides, and emulsifiers like Sorbitan Olivate, Beeswax, Cetyl Dimethicone), your cream is an emulsion.

An emulsion is designed to blend water and oil phases together. Therefore, in principle, your base cream can accommodate both water-soluble and oil-soluble ingredients.

However, the method of adding depends on the solubility of the specific ingredient:

• Water-soluble ingredients should ideally be dissolved in the water phase (or a small amount of water as discussed above) before incorporation.
• Oil-soluble ingredients should ideally be dissolved in the oil phase (or a compatible oil/silicone) before incorporation.

For the specific ingredients you mentioned adding (Alpha Arbutin, Nanowhite, Licorice Extract, Zinc PCA), they are primarily water-soluble or water-dispersible. Therefore, the staff's suggestion to pre-mix them in a small amount of water before adding to your cream is the correct approach for these particular additives. If you wanted to add an oil-soluble extract in the future, you would need to dissolve it in an oil compatible with your cream first.