Fabrication of nanomicelle with enhanced solubility and stability of camptothecin based on α,β-poly[(N-carboxybutyl)-l-aspartamide]–camptothecin conjugate

This research is aimed to develop a nanomicelle delivery system in order to enhance the solubility and stability of camptothecin (CPT) in aqueous media. In this case, α,β-poly[(N-carboxybutyl)-l-aspartamide] (PBAsp)–CPT was conjugated by the esterification between PBAsp and 20-OH of CPT, and hence used to fabricate nanomicelles with a particle size between the pore size of blood capillary in normal tissue and that in tumor tissue. It was worthy of note that the drug-loaded system of PBAsp–CPT nanomicelle improved the solubility and stability of CPT in aqueous media. However, with an increase of the CPT loading in PBAsp–CPT, the solubility sharply decreased. Meanwhile, the sizes of PBAsp–CPT nanomicelles showed a tendency of increase. Moreover, the drug release of PBAsp–CPT nanomicelles displayed a linear sustaining profile, and hence resulted in the essential decrease of cytotoxicity to L929 cell line. The assembled nanomicelles based on the PBAsp–CPT conjugates showed a great potential as polymer prodrug of tumor therapy, and the controlled nano-scale might achieve the passive tumor targeting.