Recent advances in polymer drug conjugates.

Polymer drug conjugates play an important role in the delivery of drugs. In the polymeric drug conjugates, the bioactive agent is combined covalently with polymer to achieve the efficient delivery of bioactive agents in the required or specific period of time along with the enhancement of permeability and retention time. A large number of biodegradable polymers have been widely used in the area of biomedical science. Among them, polyphosphazene, is a biodegradable polymer having versatile nature because of its two chlorine atoms attached on both sides of phosphorus atom of its polymeric backbone, it can be easily replaced by nucleophilic substitution reaction. A plenty of work has been explored for its biomedical applications such as tissue engineering, vaccine drug delivery, polyphosphazene- anticancer drug conjugates with doxorubicin, paclitaxel, platinum complexes, methotrexate and gemcitabine for the targeted drug delivery etc. This review is focused on the recent advances in the biomedical applications of polyphosphazene-drug conjugates.