摘要
Camptothecin(CPT)-based drugs always undergo the reversible,pH-dependent lactone ring-opening reaction,yielding the inactive but toxic carboxylate form.Self-assembly strategy provides an effective route for preserving their bio-stability.In this article,nano-sized self-assemblies from CPTbased antitumor drugs were simply built up by directly diluting the stock dimethylsulfoxide solutions of(S)-(t)-CPT,(S)-10-hydroxyl camptothecin and carboxylic CPT with water/phosphatebuffered saline solution.Because of their different molecular structures in A-ring or modification on the 20-OH group,CPT self-assembled into helical nano-ribbons,whereas 10-hydroxycamptothecin and carboxylic CPT self-aggregated into flat nano-ribbons and cylindric nano-rods,respectively.Attractively,the self-assembly of CPT-based drugs could occur within 1 min at a low concentration of 1×10^(-5)M.Adopting the J-type self-aggregation,self-assemblies were stable in aqueous solution and could effectively protect the CPT-based drugs from hydrolysis,which thereby kept their bioactivity for tumor therapy.
基金
This work was supported by the National Natural Science Foundation of China(51125014,51233003 and 21474077)
the Ministry of Science and Technology of China(2011CB606202).