Role of Lipids in Enhancing Splenic Uptake of Polymer-Lipid (LIPOMER) Nanoparticles

A number of intracellular infections are primarily resident in the spleen. The aim of present study was to evaluate the splenotropic potential of lipids reported in the preparation of solid lipid nanoparticles. A nanoparticulate system comprising of a hydrophilic polymer-lipid (LIPOMER) combination was selected. Nanoparticles of doxycycline hydrochloride, a highly water soluble drug and drug of choice for intracellular infections, were prepared by nanoprecipitation. Nanoparticles exhibited high drug entrapment efficiency and nanosize. Location of lipid in the nanoparticles was evaluated by transmission electron microscopy. Comparative biodistribution studies in rats, using ^99mTc labeled formulations revealed enhanced splenic uptake of nanoparticles containing glyceryl monostearate as lipid. Further, the organ associated radioactivity of liver and spleen suggested significant enhancement in splenic uptake at concentrations of glyceryl monostearate (≥25%). Our findings suggest the splenotropic potential of glyceryl monostearate which could have ramifications for delivery of a number of agents to the spleen.