The effect of replacing fragrance compounds on emulsion rheology

Fragrance is a common ingredient in personal care and household products, used to establish product branding, while also enhancing user’s sensory experience with the product. The number of reported allergies due to personal care products is slowly rising, and the ingredients found in fragrance compounds are commonly the skin sensitisers at the centre of the problem. The Scientific Committee on Consumer Safety (SCCS) as well as the International Fragrance Association (IFRA) both publish reports and guidelines on allowed fragrance usage levels, which often change in updated amendments. When a fragrance usage level has been changed (or in some cases, a fragrance banned), formulators must ensure that their re-formulated products show the same stability and usage characteristics as the original products.

This study focuses on two common fragrance families, Florals and Musks, which contain ingredients likely to be banned due to skin sensitisation and contact allergy. The proposed replacement for the two problematic ingredients in the Floral family, aldehydes Lyral and Lilial, is a tetrahydropyran Florol. In the Musk family, the polycyclic nitro-musks Galaxolide and Musk Ketone could be replaced by macrocyclic musks, such as Habanolide. The aim of the study was to investigate whether and to what extent the proposed replacements Florol and Habanolide change the rheological properties of the original products, therefore, to determine whether they are suitable as direct replacements.