Applications

Consistency in the stability/structure characteristics of an emulsion is a necessary prerequisite to achieve the desired final product quality. Two reliable and well-established parameters that are intimately related to the physical stability and structure of an emulsion are particle (droplet) size and zeta potential (surface charge). Topical delivery systems (TDS) are many and varied; they include creams and lotions based on O/W and W/O emul-sions. TDS are complex, multicomponent, heterogeneous compositions that require much iteration to attain the final desired formulation; many factors Cosmetic Delivery Systems Acoustic Attenuation Spectroscopy 24 play a role in determining the outcome. Additionally, cosmetic and phar-maceutical emulsions cannot be diluted without consequence to the droplet size and, hence stability. Additionally, product performance behavior such as delivery of actives, efficacy (e.g. SPF) and aesthetic acceptability (e.g. spread