The goal of this study was to test the feasibility to load non-ordered, non-spherical mesoporous silica with the model drug paracetamol, and subsequently coat the loaded particles using one single pilot scale fluid bed system equipped with a Wurster insert. Mesoporous silica particles (Davisil(®)) with a size ranging from 310 to 500μm and an average pore diameter of 15nm were loaded with paracetamol to 18.8% drug content. Subsequently, loaded cores were coated with ethylcellulose to obtain controlled drug release. Coating processing variables were varied following a full factorial design and their effect on drug release was assessed. Increasing coating solution feed rate and decreasing fluidizing air temperature were found to increase drug release rates. Increasing pore former level and decreasing coating level were found to increase drug release rates. The release medium's osmolality was varied using different sodium chloride concentrations, which was found to affect drug release rates. The results of this study clearly indicate the potential of non-ordered, non-spherical mesoporous silica as a reservoir carrier for the controlled release of drugs. Although non-spherical, we were able to reproducibly coat this carrier using a bottom spray fluid bed system. However, a major hurdle that needs to be tackled is the attrition the material suffers from during fluid bed processing.

Polyethylene glycol (PEG) is considered the gold standard to prepare long circulating nanoparticles. The hydrophilic layer that sterically protects PEGylated nanomedicines also impedes their separation from biological media. In this study, we describe an immunoprecipitation method using AntiPEG antibodies cross-linked to magnetic beads to extract three types of radiolabeled PEGylated systems: polymeric nanoparticles, liposomes, and therapeutic proteins. The potential of the method is emphasized by isolating these systems after in vivo administration and ex vivo incubation in human biological fluids. Immunoprecipitation also allows a unique perspective on the size distribution of nanoparticles in the bloodstream after intravenous and intraperitoneal administrations. Further, we highlight the potential of the approach to inform on nanomaterial-associated drug in plasma as well as help characterize the protein corona. Altogether, we believe this method answers an unmet need in nanomedicine research and will contribute a fresh perspective on the interactions of nanomedicines with biological systems.