Big family of nano- and microscale drug delivery systems ranging from inorganic materials to polymeric and stimuli-responsive carriers as well as drug-conjugates

Traditional drug administration routs suffer from low selective distribution, poor solubility, fast elimination and damaging adjacent healthy tissues (especially in cancer therapy). Thus, drug delivery systems (DDSs) which could deliver drug to target site have broadly been investigated to upsurge the drug bioavailability and to diminish its side effects. Nanocarriers can quickly internalize into cells through intracellular endocytic routes and efficiently release pharmaceuticals at desired place. Micro- and nanoparticle formulations are of great interest as materials for delivery of drugs. Microparticles can be utilized to prepare longstanding stock formulations that are stable for weeks to months and injected through intramuscular and/or subcutaneous methods. Nanocarriers are achieved from numerous inorganic and organic compounds such as polymers, dendrimers, lipids, proteins, antibodies, peptides, cells, metals and metal oxides (e.g. iron oxide, silver and gold), non-metal oxides (silica), quantum dots, carbon nanotubes and mesoporous materials. Assembly of these materials can produce several nanoscale architectures including microspheres, sheets, conjugates, micelles, vesicles, polymer nanoparticles, polyplexes and liposomes in which drug molecules are conjugated chemically or complexed/encapsulated physically. Stimuli responsive nanocarriers are delivery vehicles that are able to change their structures (such as degradation or decomposition), conformations or compositions to response internal and/or external biochemical and/or physical stimuli that help controlled release of encapsulated pharmaceuticals into diseased tissues. This review presents a comprehensive study on big family of nano- and micromaterials used as DDSs ranging from inorganic nanomaterials to polymeric nanocomposites and stimuli-responsive carriers as well as drug conjugates.