Clay minerals for innovative pharmaceutical dosage forms

This presentation aims to illustrate the use of inorganic materials, in particular clays, useful to design and realize innovative dosage forms, safe, practical to use and advantageous for the patient/user in terms of usability and safety. Anionic and cationic clays show a typical lamellar structure [1] exploited largely in health field. In fact the spaces between lamellae can store both inorganic and organic molecules as well as long chains of polymers (composites). This allows to project and realize many and different innovative and “smart”formulations for numerous applications [2]. Over the many years of study dedicated to these materials, some clays, both synthetic and natural, stable and biocompatible have been selected and studied. Anionic clays (hydrotalcites) containing magnesium-aluminum and zinc-aluminum have been largely used for both innovative formulations for buccal-oral use [3-5] and for dermatologic use [6-8]. In general they are able to improve the solubilization of poorly soluble molecules [4-5, 9], to control the release of the active ingredients and to protect the intercalated molecules, also from UV rays [6, 8]. In topical formulations they contribute to improve mechanical resistance as well as the rheological properties in the case of semisolid formulations [6-8]. More recently the ability of some cationic clays, belonging to phyllosilicate family, to interact with polymers has been studied. This has allowed the realization of suitable formulations such as hydrogels and films to be used in the cosmetic field but above all in the treatment of chronic wounds [10]. The use of these materials, before their introduction in the formulations, requires a depth characterization in order to know all the chemical and physical characteristics of the clay (e.g. RX, DSC, FTIR, SEM, particle size, BET analysis). Further studies must be performed also on the inorganic-organic hybrid. The latter, once introduced in the final product, will have different behaviour due to the kind and the composition of dosage form. The research carried out will show the use of anionic (hydrotalcites) and cationic (bentonite) clays for the realization of buccal bioadhesive tablet, oral tablet (both for immediate and gastroretentive release), semisolid formulation for sunscreen stabilization, polymeric bioadhesive films for skin application. The developed products can be classified as medicines, medical devices, cosmetics, nutraceutics, novel food according to specific laws. All studies were performed taking into account the regulatory aspects, and the official guidelines and rules as well as the respect for the sustainability and the environment.