ABSTRACT
Products formulated by cosmetic chemists are intended to perform a variety of ‘‘miracle’’ functions such as reshaping hair, delivering fragrance, smoothing and softening the skin, imparting color to the face, and cleansing the entire body. Chemists can deliver many of these miracles by using a variety of technologies, which have been described in this book. In using these technologies to develop products, chemists must be aware of the formulation issues that might prevent the product from performing optimally. Assessing the product stability is a critical part of this formulation process. This chapter discusses the basic principles of stability testing of cosmetic delivery systems. We will begin with a general definition of stability testing and move on to problems encountered by specific formula types. We will conclude this section with a discussion of stability issues that are not necessarily, directly related to the formulation, such as processing and packaging.
