Solid lipid nanoparticles in lymph and plasma after duodenal administration to rats.

PURPOSE: To evaluate the uptake and transport of solid lipid nanoparticles (SLN), which have been proposed as alternative drug carriers, into the lymph and blood after duodenal administration in rats. METHODS: Single doses of two different concentrations of aqueous dispersions of unlabelled and labelled SLN (average diameter 80 nm) were administered intraduodenally to rats. At different times, samples of lymph were withdrawn by cannulating the thoracic duct and blood was sampled from the jugular vein. Monitoring continued for 45 and 180 minutes, for unlabelled and labelled SLN respectively. The biological samples were analysed by photon correlation spectroscopy (PCS), transmission electron microscopy (TEM) and gamma-counting. RESULTS: TEM analysis evidenced SLN in lymph and blood after duodenal administration to rats: the size of SLN in lymph did not change markedly compared to that before administration. The labelled SLN confirmed the presence of SLN in lymph and blood. CONCLUSIONS: The uptake and transport of SLN in the lymph, and to a lesser extent in the blood, were evidenced. The in vivo physical stability of SLN may have important implications in designing drug-carrying SLN.