Clay-based drug-delivery systems: what does the future hold?

Clays for drug delivery have been used from ancient time due to the large availabilityof clay minerals and their unprecedented properties. The empirical use of nanoclaysfrom the past is converted in a stimulating scientific task aimed at building upnanoarchitectonic vehicles for drug delivery in a targeted and stimuli-responsivefashion. Here the historical aspects are discussed; next the modern examples ofapplications of different clay-based materials are discussed. A special focus is given tohalloysite clay nanotubes, which are an emerging and very promising nanomaterial fordrug-delivery purposes due to its special morphology and unique chemical properties.Advantages and limitations of these natural nanomaterials are critically discussedpointing out the future perspectives and directions for further research.