Uses of clay minerals in semisolid health care and therapeutic products

Clay minerals are included in several health care formulations. In particular, they are presented in many semisolid preparations with different functions, including stabilization of suspensions and emulsions, viscosizing and other special rheological tasks, protection against environmental agents, adhesion to the skin, adsorption of greases, control of heat release, etc. These functions are possible because of the special disposition of clay mineral particles when dispersed in polar solvents, due to their high surface areas and colloidal dimensions. When necessary, clays are processed or even modified to exalt or change some properties and new claylike materials with special features are also synthesized. Finally, clays are frequently used concomitantly with other rheological modifiers to obtain synergic effects, influencing the stability and/or other technical properties of the health care products. This paper reviews the properties of clay mineral dispersions and the different functions derived from those properties, providing examples of applications in products intended to fulfil health care aims. (c) 2006 Elsevier B.V. All rights reserved.