Diffusion enhancement of drugs by loaded nanoparticles in vitro

1. Dalargin, a Leu-enkephaline analogue, does normally not pass the blood-b rain barrier (BBB). When it was adsorbed onto the surface of polybutylcyano acrylate, nanoparticles dalargin can cross the BBB and induce central analg esic effects after intravenously as well as after oral application. 2 The mechanisms of this effect are unknown. Therefore, the authors evaluat ed whether neuronal transport was involved in this effect. In hippocampal s ynaptosomes and in tissue slices in vitro the active neuronal uptake and di ffusion processes were determined by use of labelled D-aspartate as a marke r of the aspartate/glutamate transporter and orotic acid as marker of diffu sion. 3. Transporter-mediated uptake into hippocampal tissue preparations was not altered in comparison to control whereas diffusion processes were enhanced . These data indicate that the nanoparticles can modify neuronal uptake mec hanisms.