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.