Uses of clay minerals in semisolid health care and therapeutic products.

6 figures, 2 tables.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 clay-like 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.This paper received support from DGES project MAT2003-06606 and Group RNM-0179 of the Junta de Andalucía (Spain). We wish to express our gratitude to Prof. Ian MacCandless (Department of English and German Philology, University of Granada) for assisting us with the English version of the text.Peer reviewe