Gels with interpenetrating polymer networks were prepared with N-vinylacetamide (NVA) and acrylic acid (AAc) as novel substrates for transdermal therapeutic systems. The gelation of NVA at 1 M in AAc gel Sustained the amphiphilic character, and a poorly water-soluble drug was kept in the gel with ethanol as solvent. Mechanical strengths were five times larger in value than those of simple poly(N-vinylacetamide) gels.