ABSTRACT
This chapter discusses the preservation of products designed for use on two different parts of the body, the hair and the skin. It also discusses the problem of product that preservation from the chemical viewpoint of both the product and the preservative system. The chapter covers shampoos, conditioners, skin lotions and creams and sun protection products. Sun protection products are generally emulsions which contain materials capable of preventing UV radiation from reaching the skin. The most important consideration in the functionality of acids is pH. The water solubility of these esters decreases with increasing alkyl chain length whereas their functionality against fungi increases. A selection of preservatives which are allowed for use in cosmetic products include acids, p-hydroxybenzoic acid esters, phenols and alcohols, formaldehyde and its donors, 2-bromo-2-nitropropan-1,3-diol, cationics, isothiazolones, miscellaneous.
