Nanocarrier Systems for Drug Targeting to Cancer Cells

Abstract

Generally, Nanoparticles (NPs) can offer many unique features for the potential targeted delivery of therapeutics for bone cancer. The advantages of using NPs may include: (1) carrying the drug to its destination while keeping the drug concentrated so that once endocytosed by cells, the drug can maximize its effect; (2) protecting the drug from being dispersed or degraded by body fluids and increasing the circulation time or retention time in the body; (3) increasing the solubility of some hydrophobic drugs due to the large surface area of NPs; and (4) loading other targeting molecules to achieve specific delivery via surface modification of NPs. The drugs delivered for bone diseases include traditionally used drugs such as antibiotics and chemotherapeutics, and gene therapy reagents like plasmid deoxyribonucleic acid (DNA) or small interfering ribonucleic acid (siRNA). Upon tailoring an ideal therapeutic delivery system for treating bone cancer, it should confine the drug pharmacological activity specifically to bone sites, with negligible side effects at other body tissues. A suitable targeting moiety (ligand), responsible for targeting specific bone tissues or specific cell types (Osteoblast, osteoclast, osteocyte or hydroxyl apatite) with minimal distribution to other tissues after systemic administration, should be selected. Recently, various targeting moieties such as tetracycline, acidic oligopeptides, estradiol analogues, BPs (ALN) and many others have been used to target different therapeutics to bone tissues. In the last few decades, biological and drug delivery research has emerged comprehensive strategies such as the use of multi-functional delivery systems. Through a synergistic effect, multi-functional carriers are capable of overcoming distinct physiological barriers and delivering therapeutic payload(s) and/or image contrast enhancement agents to target sites in the body. These multi-functional carriers share three