To investigate the delivery of hydrophobic therapeutic agents, a novel class of interpenetrating networks (IPNs) was synthesized and composed of two net-Works: methacrylic acid grafted With poly(ethylene glycol) tethers, P(MAA-g-EG) and poly(n-butyl acrylate) (PBA). The hydrophilic P(MAA-g-EG) networks are pH-responsive hydrogels, capable of triggered release of an encapsulated therapeutic agent, such as a low molecular weight drug or a protein, when it passes from she stomach (low pH) to the upper intestine (neutral pH). PBA a hydrophobic homopolymer that affect the IPN swelling behaviour, the therapeutic. agent loading efficiencies in IPNs, and solute release profiles from IPNs In dynamic swelling conditions, IPNs had greater swelling ratios than P(MAA-g-EG), but in equilibrium swelling conditions the IPN swelling ratio decreased with increasing PBA content. Loading efficiencies of the Model therapeutic agent fluorescein ranged from 21-44%. Release studies from neat P(MAA-g-EG) and the ensuing IPNs 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 hydrophilicity of the carriers used in these studies.