Get access

pH-responsive hydrogels with dispersed hydrophobic nanoparticles for the delivery of hydrophobic therapeutic agents

Authors

  • Cody A Schoener,

    1. Department of Chemical Engineering, University of Texas at Austin, Austin, TX 78712, USA
    Search for more papers by this author
  • Heather N Hutson,

    1. Department of Biomedical Engineering, University of Texas at Austin, Austin, TX 78712, USA
    Search for more papers by this author
  • Nicholas A Peppas

    Corresponding author
    1. Department of Chemical Engineering, University of Texas at Austin, Austin, TX 78712, USA
    2. Department of Biomedical Engineering, University of Texas at Austin, Austin, TX 78712, USA
    3. College of Pharmacy, University of Texas at Austin, Austin, TX 78712, USA
    • 1 University Station C0400, Austin, TX 78712, USA.
    Search for more papers by this author

Abstract

To investigate the delivery of hydrophobic therapeutic agents, a new class of polymer carriers was synthesized. These carriers are composed of two components: (i) a pH-responsive hydrogel composed of methacrylic acid grafted with poly(ethylene glycol) tethers, P(MAA-g-EG), and (ii) hydrophobic poly(methyl methacrylate) (PMMA) nanoparticles. Before the P(MAA-g-EG) hydrogel was crosslinked, PMMA nanoparticles were added to the solution and upon exposure to UV light they were photoencapsulated throughout the P(MAA-g-EG) hydrogel structure. The pH-responsive behavior of P(MAA-g-EG) is capable of triggered release of a loaded therapeutic agent, such as a low molecular weight drug or protein, when it passes from the stomach (low pH) to upper small intestine (neutral pH). The introduction of PMMA nanoparticles into the hydrogel structure affected the swelling behavior, therapeutic agent loading efficiency, and solute release profiles. In equilibrium swelling conditions the swelling ratio of nanoparticle-containing hydrogels decreased with increasing nanoparticle content. Loading efficiencies of the model therapeutic agent fluorescein ranged from 38% to 51% and increased with increasing hydrophobic content. Release studies from neat P(MAA-g-EG) and the ensuing P(MAA-g-EG) hydrogels containing nanoparticles indicated that the transition from low pH (2.0) to neutral pH (7.0) triggered fluorescein release. Maximum fluorescein release depended on the structure and hydrophobicity of the carriers used in these studies. Copyright © 2012 Society of Chemical Industry

Get access to the full text of this article

Ancillary