HEMA-based methacrylic carriers incorporating ketoprofen: Chain flexibility and swelling behaviour

The chain flexibility, swelling and release behaviour of several copolymer systems of pharmacological interest have been studied. The systems are copo lymers of 2-hydroxyethyl methacrylate with two support comonomers, i.e. N-( 4-hydroxyphenyl) methacrylamide and N-[4-(2-hydroxy)ethoxyphenyl] methacryl amide and copolymers of 2-hydroxyethyl methacrylate with these carrier stru ctures bearing ketoprofen (N-{4-[2-(3-benzoylphenyl)propionyloxy]pheny}meth acrylamide and N-{4-[2-(3-benzoylphenyl)propionyloxy]2-ethoxyphenyl} methac rylamide). In these copolymers ketoprofen was attached via different spacer groups, i.e, 4-aminophenoxy and 4-amino-ethoxyphenyl. The chain structures are discussed on the basis of reactivity ratios. The properties of the pol ymeric drugs and of the parent carriers were studied comparatively by DSC a nd through the swelling of films from DMF solutions in pH 7.4 buffers. Data are discussed in terms of chain flexibility and swelling.