Liquid Powder Formulation with Encapsulated Salicylic Acid

Regarding your formula for a liquid powder using Encapsulated Salicylic Acid (Powder, Timed-Release), Zinc Oxide (Micronized), Polyaminopropyl Biguanide, and water:

It is correct that Encapsulated Salicylic Acid (Powder, Timed-Release) is a powder ingredient that disperses rather than dissolves in a formulation. It is typically recommended for use in thicker bases like gels or creams, as the viscosity helps keep the powder particles suspended evenly throughout the product, preventing settling.

Similarly, Zinc Oxide (Micronized) is also a powder that needs to be dispersed in the base, and it will not dissolve in water.

Using these ingredients in a thin water-based formula, as in your liquid powder recipe, is possible. However, because both Encapsulated Salicylic Acid and Zinc Oxide are dispersed powders and the base is mostly water, the powders will settle over time when the product is left standing.

Therefore, as the previous staff reply indicated, it is necessary to shake the bottle well before each use to ensure that the Encapsulated Salicylic Acid and Zinc Oxide powders are evenly dispersed in the water base before you apply the product. This will help ensure you get the intended concentration of the active ingredients with each use.

Polyaminopropyl Biguanide in your formula is a water-soluble preservative and will not contribute to the settling issue.

In summary, your liquid powder formulation is feasible, but regular and thorough shaking before application is crucial due to the nature of the dispersed powder ingredients in a thin water base.