Albumin nanoparticles (ANPs) offer unique advantages for antitumor drug delivery system, including non-immunogenicity and inherent tumor-targeting capacity. At present, only a few products, such as ABRAXANE® and FYARRO™, have been approved for clinical applications. The poor affinity of doxorubicin (DOX) for albumin, coupled with its numerous severe adverse reactions, poses challenges in the fabrication of desirable albumin nanoparticles loaded with DOX. In this study, we developed prodrugs by conjugating fatty acids of varying lengths with DOX. Our aim was to investigate the balance between efficacy and safety through the selection of appropriate modules. We synthesized five pH-sensitive doxorubicin-fatty acid prodrugs. Compared to free DOX, all DOX prodrug ANPs exhibited a uniform size distribution with desirable sizes of 150 nm. Additionally, DOX prodrugs with hydrazone bonds remained intact in blood circulation while releasing DOX within tumor cells. Significantly, the characteristics of prodrug ANPs were considerably influenced by the length of fatty acids, impacting their in vivo pharmacokinetics, antitumor effectiveness and tumor accumulation. This research offers a detailed understanding of the length of fatty acid influence on DOX-fatty acid prodrug-based ANPs, and it builds a good platform for creating ANPs which prioritize high drug loading, high efficiency, and minimal side effects.

Small-molecule prodrug nanoassemblies have emerged as efficient antitumor drug delivery systems. However, in the case of camptothecins-based prodrug nanoassemblies, linear aliphatic side chain modification often results in rod-shaped or irregularly shaped nanoassemblies, which are highly unfavorable for sterilization through filtration, and may cause capillary blockage upon intravenous injection. The rational design of camptothecins-based prodrug nanoassemblies remains a challenge. Herein, we propose that branched aliphatic alcohol (BAA) functionalization could fine-tune the structure-tolerance-antitumor efficacy axis of prodrug nanoassemblies. Correspondingly, four SN38-BAA prodrugs were synthesized by conjugating 7-ethyl-10-hydroxycamptothecin (SN38) with BAAs of varying lengths via a tumor redox-responsive disulfide bond, which self-assemble into uniform spherical nanoparticles. The length of BAA was found to significant impact the multiple drug delivery process, including colloidal stability, drug release profiles and pharmacokinetics. Overall, SN38-C21 NPs (SN38-11-heneicosanol nanoparticles), featuring the longest BAA, showcased multiple therapeutic advantages, ultimately culminating the optimal antitumor efficacy and tolerance. The findings underscore the potential of BAA functionalization in strengthening the therapeutic outcomes of prodrug nanoassemblies, and provide valuable insights for developing translational camptothecins-based nanomedicines.

Prodrug-based nanoassembly emerges as a hopeful way for the efficient delivery of antitumor drugs, with carrier-free structure and ultra-high drug loading. Carbon chains are widely used to design self-assembling prodrugs. The impacts of the length of carbon chains on the self-assembly stability, drug delivery efficiency and antitumor effect of prodrugs have not been fully elucidated. Here, three paclitaxel prodrugs were synthesized by conjugating paclitaxel with octanol (C₈), decanol (C₁₀) or dodecanol (C₁₂) through disulfide bond. The three prodrugs could form homogeneous nanoparticles, with over 50% drug loading and redox dual-responsivity. Interestingly, the length extension of carbon chains ameliorates the self-assembly and the colloidal stability of prodrugs, thus improving the drug delivery efficiency. The optimal paclitaxel-dodecanol prodrug nanoassemblies exhibit better antitumor efficacy than Taxol and Abraxane. These findings are meaningful for the rational design of advanced nanomedicines in cancer therapy.