Active targeting tumor therapy using host-guest drug delivery system based on biotin functionalized azocalix[4]arene.

Host-guest drug delivery systems (HGDDSs) provided a facile method for incorporating biomedical functions, including efficient drug-loading, passive targeting, and controlled drug release. However, developing HGDDSs with active targeting is hindered by the difficult functionalization of popular macrocycles. Herein, we report an active targeting HGDDS based on biotin-modified sulfonated azocalix[4]arene (Biotin-SAC4A) to efficiently deliver drug into cancer cells for improving anti-tumor effect. Biotin-SAC4A was synthesized by amide condensation and azo coupling. Biotin-SAC4A demonstrated hypoxia responsive targeting and active targeting through azo and biotin groups, respectively. DOX@Biotin-SAC4A, which was prepared by loading doxorubicin (DOX) in Biotin-SAC4A, was evaluated for tumor targeting and therapy in vitro and in vivo. DOX@Biotin-SAC4A formulation effectively killed cancer cells in vitro and more efficiently delivered DOX to the lesion than the similar formulation without active targeting. Therefore, DOX@Biotin-SAC4A significantly improved the in vivo anti-tumor effect of free DOX. The facilely prepared Biotin-SAC4A offers strong DOX complexation, active targeting, and hypoxia-triggered release, providing a favorable host for effective breast cancer chemotherapy in HGDDSs. Moreover, Biotin-SAC4A also has potential to deliver agents for other therapeutic modalities and diseases.