Advances in medical uses for alumino-silicate clay minerals

• Autores: Industrial Minerals, Frank Hart
• Localización: Industrial Minerals, ISSN 0019-8544, Nº. 564, 2014 (Ejemplar dedicado a: Septiembre)
• Idioma: inglés
• Texto completo no disponible (Saber más ...)
• Resumen

  • Halloysite is chemically very similar to kaolinite but the alumino-silicate sheets are rolled into tubes. Major deposits occur at Matauri Bay in New Zealand, owned by Imerys, and at the Dragon mine in Utah, owned by Applied Minerals. I-Minerals is currently developing a new deposit near Bovill in northern Idaho, which is characterised by a high aspect ratio (longer tube length).

    Halloysite tubes can be enlarged internally to increase volume capacity by etching the lumen with suitable acids. Active pharmaceutical preparations are loaded into the hollow tubes by vacuum techniques. The release rate can be tailored from hours to days by 'capping' the ends of the tubes, which is achieved by reacting the internal chemical agents with metal ions, or using starch. An alternative method that is also used, is to encapsulate the HNT with polymers such as polyethyleneimine.

    HNT competes against synthetic engineered carbon nanotubes but is significantly cheaper at approximately $140/lb versus $4000/lb, depending on the supplier and grades. Additionally, there are concerns that carbon nanotubes may have adverse health effects whereas halloysite is non-toxic.