Novel lipophilic SN38 prodrug forming stable liposomes for colorectal carcinoma therapy

Abstract

Jing Xing,*,1,2 Xiquan Zhang,*,3 Zhe Wang,4 Huanqing Zhang,3 Peng Chen,1,2 Gaoxin Zhou,5 Chunlong Sun,6 Ning Gu,1,2 Min Ji1,21School of Biological Science and Medical Engineering, Southeast University, Nanjing 210096, People’s Republic of China; 2School of Biological Science and Medical Engineering and Collaborative Innovation Center of Suzhou Nano Science and Technology, Southeast University, Suzhou 215123, People’s Republic of China; 3Nanjing Institute of Pharmaceutical Research and Development, Chia-Tai Tianqing Pharmaceutical Group Co. Ltd, Nanjing 210023, People’s Republic of China; 4Emergency Department, The Second Affiliated Hospital of Nanjing Medical University, Nanjing 210029, People’s Republic of China; 5School of Biomedical Engineering, Shenzhen University, Shenzhen 518071, People’s Republic of China; 6College of Biological and Environmental Engineering, Binzhou University, Binzhou 256603, People’s Republic of China*These authors contributed equally to this workBackground: SN38 (7-ethyl-10-hydroxy camptothecin), as a potent metabolite of irinotecan, is highly efficacious in cancer treatment. However, the clinical utility of SN38 has been greatly limited due to its undesirable properties, such as poor solubility and low stability.Materials and methods: In order to overcome these weaknesses, moeixitecan, a lipophilic SN38 prodrug containing a SN-38, a trolox, a succinic acid linker, and a hexadecanol chain, was loaded into liposomal nanoparticles by ethanol injection method.Results: Experiments showed that the moeixitecan-loaded liposomal nanoparticles (MLP) with a diameter of 105.10±1.49 nm have a satisfactory drug loading rate (90.54±0.41%), high solubility and stability, and showed sustained release of SN38. Notably, MLP exhibited better antitumor activity against human colon adenocarcinoma cells than irinotecan, a FDA-approved drug for the treatment of advanced colorectal cancer. Furthermore, xenograft model results showed that MLP outperformed irinotecan in terms of pharmacokinetics, in vivo therapeutic efficacy and safety. Finally, we used molecular dynamic simulations to explore the association between the structure of MLP and the physical and functional properties of MLP, moeixitecan molecules in MLP folded themselves inside the hydrocarbon chain of the lipid bilayer, which led an increased acyl chain order of the lipid bilayer, and therefore enhanced the lactone ring stability protecting it from hydrolysis.Conclusion: Our MLP constructing strategy by liposome engineering technology may serve a promising universal approach for the effective and safe delivery of lipophilic prodrug.Keywords: SN38, lipophilic prodrug, liposomes, molecular dynamic simulations, cancer therapy

Keywords

• SN38
• lipophilic prodrug
• liposomes
• Molecular dynamic simulations
• Cancer therapy