Targeted drug delivery approaches for the management of tumors

The treatment of tumors requires specific and selective drug delivery approaches capable of efficiently eliminating the root cause of oncogenesis. In this context, targeted drug delivery strategies are the preferred choice due to their exceptional recognition of tumor cell biology and their high transfection efficacy within the tumor microenvironment. The emergence of nanoscale techniques has marked significant milestones in the successful management of various types of tumors. The development of targeted delivery approaches for tumor therapeutics has gained momentum over the past few decades. However, in contrast to the plethora of successful pre-clinical studies, only a limited number of passively targeted nanocarriers have been approved for clinical use, and none of the actively targeted nanocarriers have advanced beyond clinical trials. This review delves into the major molecular principles associated with tumorigenesis, including active targeting, passive targeting, and cell-mediated targeting. It also explores the biological barriers (systemic, biological, and cellular) encountered in tumor drug delivery. Moreover, the review examines various tumor-targeted drug delivery systems that have been developed over the past decade. These systems encompass polymeric nanoparticles (micelles, nanoparticles, dendrimers, and polyplexes), lipid-based carriers (solid lipid nanoparticles, nanostructured lipid carriers, nanoemulsion), vesicular systems (liposomes, niosomes, aquasomes, and phytosomes), and inorganic nanocarriers (iron oxide nanoparticles, quantum dots, carbon-based nanoparticles, and mesoporous silica nanoparticles), all designed for the alleviation of tumors.