Formulation of Mild Shampoos and Investigation of Possible Prebiotic Effects

Abstract

Background: Recently, there has been a significant increase in the application of prebiotics in cosmetic products. Thus, this investigation aims to create two mild shampoo compositions, containing inulin; a distinguished prebiotic, and a reference shampoo. As a further step, the efficacy of formulations against strains of Staphylococcus aureus and Staphylococcus epidermidis bacteria, as well as mixed cultures of these two bacteria, was assessed.
 Materials and Methods: After formulation development, physicochemical (physical appearance, pH, percentage of solid contents, viscosity, density and stability studies) and biological evaluations (challenge test, MIC (Minimum inhibition concentration), MBC (Minimum Bactericidal Concentration) were carried out. 
 Results: The results showed that the hair and body shampoo formulas displayed good stability and maintained their physicochemical properties under different conditions over time. Furthermore, they were microbiologically safe according to the challenge test and instrumental analysis. Microbial assays indicated that Shampoo-A promoted the growth of Staphylococcus epidermidis while inhibiting the growth of Staphylococcus aureus in the presence of prebiotic active, whereas Shampoo-B inhibited the growth of both bacteria. 
 Conclusions: Although further research is required to declare the microbiome-related claims, the development of these products holds promise for positive effects on skin health and microbiome.