Multistage delivery of chemotherapeutic nanoparticles for breast cancer treatment.

Adequate drug delivery to tumors is hindered by barriers such as degradation and non-specific distribution. Nested incorporation of drug-containing nanoparticles within mesoporous silicon particles (MSVs), carriers rationally designed to enhance tumor transport, was hypothesized to result in pronounced and sustained antitumor efficacy. Paclitaxel (PTX)-containing poly(ethylene glycol)-block-poly(ε-caprolactone) (PEG-PCL) polymer micelles were favorably loaded within MSVs, after which drug release was significantly delayed. Antitumor efficacy analyses in mice bearing MDA-MB-468 breast tumors demonstrated significant tumor growth suppression following a single administration. Results highlight effective chemotherapeutic shuttling and site-specific controlled release afforded by MSVs, potentially translating towards improvements in patient outcomes and morbidity.