Azocross-linked poly(acrylic acid) for colonic delivery and adhesion specificity: synthesis and characterisation.

A new synthetic pathway to 4,4'-divinylazobenzene is presented together with a procedure for the copolymerisation of this compound with acrylic acid. The chemical structure of the synthesised series of copolymers is examined in the light of infrared spectroscopy results and nuclear magnetic resonance data. The thermal properties of the materials are assessed using a combination of thermal analysis techniques and their swelling behaviour is evaluated at physiologically relevant buffers designed to mimic the gastrointestinal environment.