Nanoscale Smart Drug Delivery Systems and Techniques of Drug Loading to Nanoarchitectures

AbstractConventional drug delivery systems suffer from less therapeutic efficiency with adverse side effects and poor specificity in action. The progression of nanoscale drug delivery systems leads to better transport, controlled delivery, and site-specific action of drugs than conventional drug delivery systems, so nano-based drug delivery systems are better option for the diagnosis and therapy of many diseases. These nanosize drug delivery systems may be organic, inorganic, or hybrid in nature. The organic nanocarriers are polymeric micelles, vesicles, nanoliposomes, dendrimer, solid lipid nanoparticles (SLNs), nanogels, carbon nanotubes, fullerenes, graphene, etc. The inorganic nanocarriers are quantum dots, gold and mesoporous silica nanoparticles (MSNs), etc. Many advanced strategies for controlled drug release and drug loading to nanocarriers have been developed. Controlled drug release at target site can be attained either by spontaneous diffusion or by applying proper stimulus. For stimulus-responsive drug release, the stimulus may be internal or external. Physical (temperature, light, ultrasonic vibrations, magnetic field, ionic strength), chemical (redox, pH), and biological stimulus (enzymes) are generally used for controlled drug release at target site. Based on the nature of nanocarriers, there is a wide choice of principles and procedures followed to load drugs to these nanostructures. Basically, drug molecules are loaded to nanocarriers by encapsulation or entrapment techniques via covalent or non-covalent bonds. Thus, improved site-specific action and optimum rate of drug release from nano drug carriers have made numerous applications almost in every division of medicine especially oncology, immunology, pulmonary medicine, orthopedics, neurology, dentistry, ophthalmology, etc.KeywordsNanomedicine Inorganic nanoparticles Organic Nanoparticles Drug loading Drug delivery Stimulus-responsive drug release