Clay nanoparticles as pharmaceutical carriers in drug delivery systems.

Clay minerals are a class of silicates with chemical inertness, colloid, and thixotropy, which have excellent physicochemical properties, good biocompatibility, low toxicity, and have high application potential in biomedical fields. These inorganic materials have been widely used in pharmaceutical excipients and active substances. In recent years, nanoclay mineral materials have been used as drug vehicles for the delivery of a variety of drugs based on their broad specific surface area, rich porosity, diverse morphology, good adsorption performance, and high ion exchange capacity. This review introduces the structures, properties, and applications of various common natural and synthetic nanoclay materials as drug carriers. Natural nanoclays have different morphologies including nanoplates, nanotubes, and nanofibers. Synthetic materials have controllable sizes and flexible structures, where mesoporous silica nanoparticles, laponite, and imogolite are typical ones. These inorganic nanoparticles are often linked to polymers to form multifunctional drug delivery systems for better pharmaceutical performance. The clay nanomaterials have typical properties, including enhanced solubility of insoluble drugs, targeting therapeutic sites, controlled release, and stimulation of responsive drug delivery systems.