Development and evaluation of the effectiveness of a solid shampoo bar

Abstract

Solid shampoo is an innovative and alternative cosmetic form of shampoo that, as it does not contain water in its composition, gains the attribute of being more sustainable. This work aims to develop, evaluate the stability, and characterize a solid shampoo formulation. Nine solid shampoo formulations were prepared by varying the concentrations of solid surfactants defined through a statistical design. The formulations, labeled F1 to F9, were submitted to the preliminary stability evaluation under different storage conditions for 30 days, in which organoleptic characteristics as well as the pH values were evaluated. Approved formulations were physically and functionally characterized. Only two formulations (F3 and F5) were approved in the stability assessment because they did not show changes in consistency, color, odor, appearance, and pH under different storage conditions. These formulations showed stable foaming, but crumbled very easily and presented low hardness, which indicates the need to adjust the concentration of consistency agents to make the formulation more resistant to breakage. The formulations demonstrated excellent cleaning and conditioning ability.