The characterisation of Pluronic P123 micelles in the presence of sunscreen agents


OBJECTIVES The triblock copolymer Pluronic® is widely used in the personal care industry, including sun protection, for its film forming and solubilisation capabilities. In this study, the effect of three commonly used organic UV filters (ethylhexyl methoxycinnamate (EMC), ethylhexyl triazone (EHT) and avobenzone (AVB)) on the structure of Pluronic P123 micelles was investigated.

METHODS The Pluronic P123 micelle structure has been investigated using dynamic surface tension, nuclear magnetic resonance (NMR) and small-angle neutron scattering (SANS).

RESULTS Dynamic surface tension results show strong interactions between the UV filters and Pluronic® evident by sharp changes in the surface activity of the latter. The NMR results have revealed the creation of a hydrophobic microenvironment special to the Pluronic PPO core group in the presence of UV filters. Some interaction with the hydrophilic EO was also recorded, albeit weaker. This is further confirmed by SANS, where the Pluronic P123 micelles interacted with varying strengths with the UV filters, resulting in sharp changes in their size and shape.

CONCLUSIONS We have demonstrated the sensitivity of the Pluronic P123 micelles to the presence of various UVA/B filters. The micelles shape varied from spherical to cylindrical as the concentration and type of the UV filters were varied. These variations in the shape are expected to have a significant effect on the sun protection factor (SPF), as it affects the solubilisation of the UV filters within a formulation in addition to the formulations’ rheological profile and film forming behaviour.


open access article


sunscreens, surfactants, emulsions, formulation/stability, small-angle neutron scattering


Ragu, P., Ruparelia, K., Venero, D.A. and Mansour, O.T. (2023), The characterisation of Pluronic P123 micelles in the presence of sunscreen agents. International Journal of Cosmetic Science,


Research Institute

Leicester Institute for Pharmaceutical Innovation - From Molecules to Practice (LIPI)