Qinghe Zhao

High loading of hydrophilic/hydrophobic doxorubicin into polyphosphazene polymersome for breast cancer therapy

UNLABELLED Breast cancer remains one of the most common cancers for females. Drug delivery based on cancer nanotechnology could improve the performance of some chemotherapeutic medicines already used in clinic. The emergence of polymersomes provided the potential to encapsulate hydrophobic/hydrophilic drugs. By modifying the weight ratio of methoxy-poly (ethylene glycol) (mPEG) chain to ethyl-p-aminobenzoate (EAB) side group, a series of amphiphilic graft polyphosphazenes (PEPs) was prepared. PEP can be tuned from micelles to polymersomes with the decrease of mPEG content via dialysis. Either hydrophilic doxorubicin hydrochloride (DOX·HCl) or hydrophobic doxorubicin base (DOX) could be encapsulated into PEP polymersomes with high payload and high encapsulation efficiency due to the strong intermolecular interaction with PEP. Compared with free DOX·HCl administration, in vivo investigation in growth inhibition of MCF-7 xenograft tumors in nude mice demonstrated that PEP polymersomes could enhance life safety without compromise of therapeutic efficacy, especially DOX·HCl loaded delivery system. FROM THE CLINICAL EDITOR In this preclinical study, polymerosomes based on PEPs were investigated as doxorubicin delivery systems, demonstrating similar efficacy but less toxicity compared to standard delivery methods.

Assembly of multilayer microcapsules on CaCO3 particles from biocompatible polysaccharides

Multilayer microcapsules were fabricated by layer-by-layer (LbL) assembly of natural polysaccharides onto CaCO3 particles, following with core removal. The micron-sized CaCO3 particles were synthesized by reaction between Ca(NO3)2 and Na2CO3 solutions in the existence of carboxylmethyl cellulose (CMC). The incorporated amount of CMC in the CaCO3 particles was found to be 5.3 wt% by thermogravimetric analysis. Two biocompatible polysaccharides, chitosan and sodium alginate were alternately deposited onto the CaCO3(CMC) templates to obtain hollow microcapsules. Regular oscillation of surface charge as detected by zeta potential demonstrated that the assembly proceeded surely in a LbL manner. The stability of the microcapsules was effectively improved by cross-linking of chitosan with glutaraldehyde. The chemical reaction was verified by infrared spectroscopy. The microcapsules thus fabricated could be spontaneously filled with positively charged low molecular weight substances such as rhodamine 6G and showed good biocompatibility, as detected by in vitro cell culture.