Clarification on Phenoxyethanol SA (eq. Optiphen Plus) Usage and Solubility

You are correct that the product description for Phenoxyethanol SA (eq. Optiphen Plus) states:

• Recommended usage rate for open container products (like cream jars): 1.25%
• Solubility: Can be dissolved in water (not more than 1.0%)

The confusion arises because you are formulating a cream, which is an emulsion containing both water and oil phases, not just a simple water solution.

Phenoxyethanol SA (eq. Optiphen Plus) is a blend of Phenoxyethanol, Caprylyl Glycol, and Sorbic Acid. While the blend has a limited solubility in water (1.0%), the components of this blend can be incorporated into the overall cream system.

Think of it this way:

1. The 1.0% solubility limit in water means that if you tried to dissolve Phenoxyethanol SA only in water, you couldn't dissolve more than 1.0% of it.
2. However, in a cream emulsion, the ingredients can distribute into both the water phase and the oil phase.
3. The recommended usage rate of 1.25% for an open-container cream is the total amount of the preservative blend needed in the final product to provide effective preservation.

Therefore, even though its solubility in water alone is 1.0%, you can still use 1.25% of Phenoxyethanol SA in your 100g cream formulation (which is 1.25g). The preservative blend will be incorporated into the emulsion system, distributing between the water and oil phases as needed, allowing it to function effectively at the recommended concentration.

In summary: The water solubility limit refers to dissolving the ingredient only in water. When used in an emulsion like a cream, the ingredient is incorporated into the entire system, and the recommended usage rate of 1.25% is appropriate for providing broad-spectrum preservation in an open container, despite its limited solubility in water alone.

Remember to add Phenoxyethanol SA in the final step of your formulation, ensuring the temperature is below 60°C and the pH is between 2.0 and 6.0 for optimal performance.