Poly(acrylic acid) superporous hydrogel (SPH) microparticles possessing a unique porous structure were used as a wicking agent to decrease disintegration time of fast-disintegrating tablets (FDTs). The compression behaviour of poly(acrylic acid) SPH microparticles was evaluated using the Kawakita equation. Effects of various SPH microparticle sizes and a 19-run fractional factorial design were evaluated. The factorial design was based on four factors consisting of ketoprofen, SPH microparticle, filler, and tableting pressure, and each factor contained three levels on the disintegration time and tensile strength of the prepared FDTs. The poly(acrylic acid) SPH microparticles existed in an amorphous state and swelled approximately 80-times in distilled water and 50-times in pH 6.8 0.2 M phosphate buffer. The compressibility of SPH microparticles increased significantly as the microparticle size increased. The FDTs made of SPH microparticles in the range of 75-106 microm showed the fastest disintegration time and higher tensile strength. SPH microparticle, tableting pressure and ketoprofen had significant effects on disintegration time and tensile strength of ketoprofen FDTs. The FDTs that were prepared with 2.5% w/w SPH microparticles of 75-106 microm at 63 MPa pressure possessed a tensile strength of 84.4 +/- 4.1 N cm(-2) and disintegrated in 15.0 +/- 2.0 s. It was concluded that the poly(acrylic acid) SPH microparticles could serve as a good super-disintegrant decreasing the disintegration time of FDTs.