Synthesis of size-tunable polymeric nanoparticles enabled by 3D hydrodynamic flow focusing in single-layer microchannels

Author Manuscript date: 2011 June 27A versatile microfluidic platform to synthesize NPs by nanoprecipitation using 3D hydrodynamic flow focusing isolates the precipitating precursors from channel walls, eliminating fouling of the channels. It is shown that this new method enables robust nanoprecipitation without polymer aggregation, regardless of the polymer molecular weight or precursor concentration implemented, where the size of the resulting polymeric NPs is tunable.David H. Koch (Prostate Cancer Foundation Award in Nanotherapeutics)National Institutes of Health (U.S.) (Grant CA119349)National Science Foundation (U.S.) (Graduate Research Fellowship

Preparation and in vivo evaluation of insulin-loaded biodegradable nanoparticles prepared from diblock copolymers of PLGA and PEG

YesThe aim of this study was to design a controlled release vehicle for insulin to preserve its stability and biological activity during fabrication and release. A modified, double emulsion, solvent evaporation, technique using homogenisation force optimised entrapment efficiency of insulin into biodegradable nanoparticles (NP) prepared from poly (dl-lactic-co-glycolic acid) (PLGA) and its PEGylated diblock copolymers. Formulation parameters (type of polymer and its concentration, stabiliser concentration and volume of internal aqueous phase) and physicochemical characteristics (size, zeta potential, encapsulation efficiency, in vitro release profiles and in vitro stability) were investigated. In vivo insulin sensitivity was tested by diet-induced type II diabetic mice. Bioactivity of insulin was studied using Swiss TO mice with streptozotocin-induced type I diabetic profile. Insulin-loaded NP were spherical and negatively charged with an average diameter of 200–400 nm. Insulin encapsulation efficiency increased significantly with increasing ratio of co-polymeric PEG. The internal aqueous phase volume had a significant impact on encapsulation efficiency, initial burst release and NP size. Optimised insulin NP formulated from 10% PEG–PLGA retained insulin integrity in vitro, insulin sensitivity in vivo and induced a sustained hypoglycaemic effect from 3 h to 6 days in type I diabetic mice

Simultaneous optimization of cisplatin-loaded PLGA-mPEG nanoparticles with regard to their size and drug encapsulation

A central composite experimental design was applied to investigate the effect of five preparative variables on the size and cisplatin encapsulation efficiency of poly(lactide-co-glycolide)-methoxy poly(ethylene glycol) (PLGA-mPEG) nanoparticles. The nanoparticles were prepared by a nano-precipitation process and were characterized with regard to their morphology by scanning electron microscopy, their size by photon correlation spectroscopy and their drug content by atomic absorption spectroscopy respectively. The preparative variables investigated were: solids concentration, aqueous to organic phase volume ratio, temperature, rate of organic phase addition in aqueous phase and agitation. The nanoparticles prepared in this study appeared to be spherical and rather homogeneous in size under the scanning electron microscope. The size and the drug encapsulation of the prepared nanoparticles ranged between 90-180 nm and 0%-40%, respectively. The fitted model could adequately describe the experimental data. The statistical analysis showed that all preparative variables studied, except temperature, affected significantly both the size and the drug loading of nanoparticles. The size was most affected by the agitation whereas the loading was most affected by the phase ratio. Significant interactions between the preparative variables were also observed. The "desirability function" approach was applied to simultaneously optimize the nanoparticles with regard to their size and cisplatin encapsulation. The predictive power of the applied model was more satisfactory in the case of nanoparticles size than with cisplatin encapsulation efficiency. It appears to be feasible to select optimum conditions for the preparation of PLGA-mPEG nanoparticles of cisplatin based on a central composite design and the "desirability function" optimization approach. © 2008 Bentham Science Publishers Ltd