Colon-specific devices based on methacrylic functionalized Tween monomer networks: Swelling studies and in vitro drug release

Colon-targeted delivery devices based on methacrylic functionalized Tween monomer networks, useful for 5-FU or Ferulic acid site-specific release, were synthesized. The basic design consists of methacrylic functionalized Tween monomer-based networks prepared with or without acrylic acid as co-monomer. The swelling behaviour and loaded drugs release from these gels was studied as a function of pH. The devices showed a strong pH-dependent swelling behaviour, allowing a maximum release at pH 7.4. The acrylic acid introduction increased the polymeric gels pores size, as evidenced by the loading efficiency increase, but also reduced the amount of released drug in basic media compared to analogous network not containing the co-monomer. This behaviour, already found in the matrix swelling, could be attributed to a slower hydrolysis kinetics of the ester bond in functionalized Tween monomers, which implies a reduced ability to absorb water from a basic medium, resulting in a lower capacity to release the loaded drug. Since our device possesses a maximum drug release in the media at pH 7.4, it could be used for colon-targeted drug delivery of both 5-FU and Ferulic acid.. (C) 2009 Elsevier Ltd. All rights reserved.