Polyphosphazenes for the delivery of biopharmaceuticals

Abstract

Polyphosphazenes (PPZs) are a relatively new family of polymers based on a nitrogen- phosphorous backbone where organic side-groups can be grafted. The synthetic route to PPZs is highly versatile such that it is possible to add many different functionalities that change completely the physicochemical and biological properties of the polymers. For instance, PPZs can be designed with a variety of organic side groups that render these materials biodegradable and highly biocompatible. Based on these positive features, PPZs have been explored for many biomedical applications including the design of numerous advanced drug delivery systems. In this area, PPZs have been particularly investigated as materials for the formulation of biopharmaceuticals of high added value. These include protein- and polynucleotide-based medicines, applications where PPZ carriers have obtained very positive results in pre-clinical models. A further area of major interest for PPZs has been vaccination, where these materials have obtained excellent results in vivo as polymer adjuvants and have advanced to clinical evaluation.