Drug delivery refers to the treatment of humans or animals by the administration of drugs or pharmaceuticals and other exotic substances. Various drug delivery technologies enhance therapeutic efficacy at the intended site of action while minimizing possible adverse reactions, primarily by affecting the absorption, distribution, metabolism, and elimination (ADME) of drug compounds. The development of medicine and biotechnology has prompted researchers to develop a large number of new drug candidates, many of which have not passed preclinical evaluation due to limited bioavailability, poor stability and low solubility. Advances in nanotechnology have greatly improved drug design and made possible targeted, safe and effective nanoparticle (NP) drug formulations. Nanodrug delivery systems show great potential in improving hydrophobic drug solubility, enhancing drug biological distribution and pharmacokinetics, and providing priority accumulation of targets. Nano delivery systems can be designed so that drugs are absorbed or combined on the particle surface, encased in a core, or dissolved in a particle matrix. The introduction of targeted parts on the particle surface can further target drug-loaded nanoparticles to specific disease sites. Some nanocarriers such as liposomes, polymer micelles, dendrimers, polymer-drug complexes, inorganic nanoparticles and carbon-based nanomaterials have been used in drug delivery dosage forms.
