Uptake of PMMA nanoparticles from the gastrointestinal tract after oral administration to rats:: modification of the body distribution after suspension in surfactant solutions and in oil vehicles

Polymethyl (2-C-14) methacrylate nanoparticles of a diameter of 130 +/- 30 nm were administered to Wistar rats as a single dose by oral gavage either in form of a suspension in saline, in saline with an additional content of 5% of polysorbate 80 or poloxamine 908, or suspended in peanut oil without or with addition of 5% oleic acid. The animals were sacrificed after 30 min, 1, 2, 4, 8 h, 1, and 4 days, the blood was collected, and different organs and tissues were removed. The gastrointestinal (GI)-tract was separated into stomach, small intestine, and colon. The contents of those parts were collected and the remaining GI-tract sections thoroughly rinsed. The radioactivity in the above organs, tissues, and GI-tract contents were determined using a scintillation counter. The radioactivity concentrations were highest in the GI-tract content and decreased rather rapidly (between 2 h and 1 day). Rather high concentrations (up to 10% of the administered dose at a given time point) also were seen in the CI-tract walls. These concentration did not correlate totally to those in the GI-tract contents. The concentration in the residual body reached 1-3% of the administered dose at a given time point. The highest concentrations in the body were observed between 15 and 60 min but remained at considerable levels for 4 days. By far the highest uptake (about 200-300% of the other preparations) was seen with the saline preparation containing 5% polysorbate 80. No significant difference appeared between saline without surfactants and peanut oil. The addition of oleic acid to the peanut oil increased the uptake of the nanoparticles by about 50%. (C) 1999 Elsevier Science B.V. All rights reserved.