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Water and Oil

By: Steve Herman
Posted: June 7, 2011, from the June 2011 issue of GCI Magazine.

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HSP also sheds light on nanotechnology. For example, carbon nanotubes are often considered insoluble or poorly soluble in organic solvents. In fact, carbon nanotubes can be often be solubilized in suitably chosen solvents, where their solubility optimization can be discovered and understood in terms of the HSPs of the constituents.

Wielding HSP

Because product developers work with thousands of chemicals intended for use on human skin and hair, as well as impact the environment, you need to know as much about their behavior as possible. Data is always best, but theoretical constructs and computer models are increasingly relied upon. For many important situations, from the partitioning of an ingredient in a cosmetic formulation to the compatibility of solvents with polymers to a predicted degree of skin permeation, the HSP is an essential tool. Areas as seemingly diverse as nanotechnology and aroma perception can be illuminated by the application of solubility parameters, making solubility parameters invaluable in understanding how materials behave and interact.


  1. S Herman, Smells great! What’s the ClogP?, GCI mag, 164 3 22–25 (1999)
  4. S Abbott, CM Hansen and H Yamamoto, Hansen Solubility Parameters in Practice, 3rd ed (2010)
  5. Sloan, B Kenneth, et al., Use of Solubility Parameters of Drug and Vehicle to Predict Flux Through Skin, J Invest Dermatol 87 244–256 (1986)

Steve Herman is president of Diffusion LLC, a consulting company specializing in regulatory issues, intellectual property, and technology development and transfer. He is a principal in PJS Partners, offering formulation, marketing and technology solutions for the personal care and fragrance industry. He is an adjunct professor in the Fairleigh Dickinson University Masters in Cosmetic Science program and is a Fellow in the Society of Cosmetic Chemists.