Compositional, technical and safety specifications of clays to be used as pharmaceutical and cosmetic products

Because of their high specific surface area, optimum rheological characteristics and/or excellent sorptive capacity, certain clay minerals such as kaolinite, talc, montmorillonite, saponite, hectorite, palygorskite and sepiolite are extensively used in the formulation of various pharmaceutical and cosmetic products. Whether as active ingredients or as ideal excipients, these minerals must comply with a number of textural and compositional requirements (concerning grain size, degree of mineral purity, water content, major and trace element contents or microbial contamination) and have specific technical properties. Their safety and stability characteristics are vitally important. This paper gives a review of the different pharmacopoeias, rules and regulations affecting the use of these natural products, whose denominations in the commercial sphere vary significantly. Particular attention is also paid to the different safety aspects associated with their processing, handling and administration.