Recent updates in nanoscale delivery systems of platinum(IV) antitumor prodrugs

Platinum-based anticancer drugs still play a crucial role in the treatment of various solid tumors such as ovarian, lung, colorectal, bladder, and breast cancer. However, their ability to cause dose-dependent systemic toxicity in patients and their inherent resistance problems in practical applications seriously hamper their clinical use. Therefore, it is still necessary to develop more platinum-based anticancer drugs to overcome these obstacles. Among them, platinum(IV) complexes, which break through the structure of cisplatin analogs with low spin d6 and an octahedral six-coordinated structure, effectively reduce toxicity due to their more inert chemical properties. Additionally, their modifiability allows for the rational design of multifunctionality that cisplatin analogs cannot achieve. Moreover, the continuous innovation of modern nanobiotechnology makes targeted delivery and the multi-drug and multi-mode combination therapy of platinum drugs possible. In particular, the combination of Pt(IV) complexes with nanocarriers is more promising due to their modifiability, providing a novel approach to reducing the adverse reaction caused by traditional platinum drugs, overcoming resistance, and enhancing therapeutic efficacy. In recent years, numerous nanoscale drug delivery systems with good biocompatibility, high drug-loading capacity, and accurate targeting have been developed. Based on our group's relevant overview published in 2020, this review focuses on appropriate supplements of the nanoscale delivery systems of Pt(IV) complexes and their updates for nearly four years.