Delivery Of Nanoconstructs In Cancer Therapy: Challenges And Therapeutic Opportunities

Nanosized constructs are widely applied to address the common drawbacks of conventional cancer therapy, such as a nonspecific biodistribution, toxicity and targeting. Nevertheless, there are several challenges in transporting sufficient drugs to the tumor using these nanoconstructs, which are discussed in this review. Additionally, the current opportunities that improve the biodistribution of nanoconstructs, tumor penetration and drug accumulation are elaborated. The distinct features of currently available strategies do not adequately fit the classical passive and active targeting categories; therefore, in this review, they are regrouped into autonomous and nonautonomous drug delivery systems. Autonomous systems are defined as self-directed systems that can enhance nanoparticle retention and distribution in solid tumors without the need to align with the blood flow direction, while non-autonomous systems primarily rely on the blood flow direction, longevity in the circulation and specific affinity to the target cells. Moreover, the effectiveness of the existing delivery systems could be further improved through the correct choice of route of administration. The role of the route of administration in improving these drug delivery methods and some recent examples of locoregional cancer therapy are discussed. These findings could stimulate improvements in the delivery of multifunctional nanoconstructs, which could facilitate successful cancer treatments.