Polyelectrolytes are of increasing interest in delivery applications involving charged and peptide drugs due to their ability to form polyelectrolyte complexes (PECs). Drug delivery systems composed of these complexes can avoid the need for chemical crosslinking while achieving desired physicochemical properties and maintaining high biocompatibility2. Natural biomaterials such as cellulose are extremely attractive for this application due to renewability, biocompatibility and non-toxicity. Chemical modifications of cellulose to include ionic and pH sensitive groups is a promising route to novel delivery biopolymers. However, the introduction of highly charged groups to the cellulose backbone is challenging due to charge repulsion and basic reaction conditions. We have utilized olefin cross metathesis as a synthetic strategy to overcome the challenges of charge repulsion in the synthesis of cellulose based polyelectrolytes. Olefin cross metathesis (CM) has proven to be a mild and efficient synthetic approach to impart a wide range of functionality to both cellulose esters3,4 and ethers1. We have been able to utilize this strategy to fully modify cellulose with pH-responsive carboxyl groups that permit strong polymer-drug interactions. We expect these interactions to lead to the enhancement of drug solubility and bioavailability. The high functional group tolerance of CM has allowed us to reach the maximum charge content possible in both cationic (quaternary ammonium) and anionic (carboxylate) polyelectrolytes with promise for controlled release of charged and poorly soluble drugs through the formation of polyelectrolyte complexes. We report the synthesis, characterization and physical properties of these novel cellulose based hypercharged polymers and initial findings of their potential in PEC drug delivery systems.

Design and synthesis of cellulose based polyelectrolytes via olefin cross-metathesis

253rd National Meeting (2017)

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