pH-sensitive deoxycholic acid dimer for improving doxorubicin delivery and antitumor activity in vivso

To develop simple and effective nano-drug delivery systems remains a major challenge in cancer treatment. Herein, we synthesized an ortho ester-linked deoxycholic acid dimer (DCA-OE), which could effectively self-assemble with doxorubicin (DOX) to form stable nanoparticles (DCA-OE/DOX NPs) by a single emulsion method. DCA-based nanoparticles had a desirable size (∼200 nm), morphology (spherical shape), and high drug encapsulation (drug loading content of ∼18.0 %, drug loading efficiency of ∼77.6 %). DCA-OE could improve the stability and solubility of DOX in physiological environment, while pH-sensitive ortho ester linkage endowed the ability to release DOX quickly in cancer cells. In vitro cytotoxicity and apoptosis verified drug-loaded dimer nanoparticles had similar toxicity with free DOX. Besides, these particles could efficiently accumulate and penetrate into human liver carcinoma cell line (HepG2) multicellular spheroids, thus resulting in enhanced antitumor effect. In vivo tests further exhibited that DCA-OE/DOX NPs had lower systemic toxicity and higher tumor inhibition effect, and its tumor inhibition rate was 84.1 %, which was far more than free DOX (49.3 %). Therefore, the strategy to link functional small molecules with ortho ester has great potentials in specific delivery of anticancer drugs.