Hydrophilic substances generally contain polar or ionic chemical groups capable of interacting with water molecules.

In cosmetic formulation, hydrophilic ingredients are often water soluble or water dispersible and are commonly incorporated into the aqueous phase.

Examples include glycerin, many amino acids, certain salts and numerous water-soluble polymers.

Relation to Solubility

Hydrophilic character does not necessarily mean that an ingredient is completely soluble in water. Solubility depends on the complete molecular structure, temperature, pH and other environmental factors.

A molecule can also contain both hydrophilic and hydrophobic regions. Surfactants are a typical example.

Importance in Formulation

Hydrophilic and hydrophobic properties are fundamental to the design of emulsions, surfactant systems, solubilizers and delivery systems.

Understanding these properties helps formulators determine where an ingredient is likely to partition and how it will behave in the finished formulation.

References

Barel, A. O., Paye, M. and Maibach, H. I. Handbook of Cosmetic Science and Technology.

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