Facile preparation of hollow crosslinked polyphosphazene submicrospheres with mesoporous shells

A facile strategy has been successfully developed to fabricate hollow crosslinked polyphosphazene submicrospheres. The mean diameter of interior cavities can be well adjusted (typically in a range from 100 to 300 nm). Interestingly, there are plenty of uniform mesopores distributing in the organic-inorganic hybrid shells. The main pore size of the mesopores is about 2–4 nm. Such hollow mesoporous submicrospheres (HMSs) possess outstanding biocompatibility and disperse ability in both aqueous and organic media. Moreover, these crosslinked polyphosphazene HMSs manifest high drug storage capacity (380 mg doxorubicin hydrochloride per gram) and excellent sustained release property (up to 15 days), hence justifying their promising applications in drug delivery.