Mucoadhesion of hydroxypropylmethacrylate nanoparticles to rat intestinal ileal segments in vitro.

The purpose of this study was to evaluate the adhesion of HPMA nanoparticles to mucus using a perfused rat ileum test system. Radiolabeled nanoparticles were prepared and deposited onto rat ileal segments in vitro. The segments were perfused and the perfusate was collected in fractions and assayed for radioactivity. Between 10 and 50% of the radioactivity was eliminated over the first 120-sec perfusion, whereas the remaining activity was firmly attached to the ileum. Among the variables tested, the time interval between nanoparticle deposition and perfusion played the major role, indicating that the mucus-nanoparticle interaction is likely to result from the diffusion of polymers into the mucus and of mucin into the polymeric matrix.