Chapter 11.6 Clays and Clay Minerals as Drugs.

This chapter discusses the applications of clays and clay materials as drugs. Clay minerals are efficient against several aggressors that cause major disorders of the gut. These beneficial effects of clay minerals (on the gastrointestinal mucosa) are associated with two mechanisms of action: (1) adsorption of the aggressors or their toxic secretions and (2) modification of the thickness and rheological properties of the adherent mucus, reinforcing the natural defenses of the gastrointestinal mucosa. At the surface of the gut, a mucus gel adheres to the epithelial cells of the mucosa. This adherent mucus is dynamic, being continuously secreted by the calceiform cells and regularly eroded by environmental aggressors present in the gut lumen. The mucus gel is largely composed of glycoprotein polymers, lipids, and proteins linked together by covalent bonds. It acts as a physical barrier protecting the mucosa against penetration by extraneous molecules and mechanical injury. By maintaining a pH gradient and competing with the epithelial surface for microorganisms, the mucus gel also acts as a chemical barrier.