Scalable preparation of poly(ethylene glycol)-grafted siRNA-loaded lipid nanoparticles using a commercially available fluidic device and tangential flow filtration.

While a number of siRNA delivery systems have been developed, the methods used in their preparation are not suitable for large-scale production. We herein report on methodology for the large-scale preparation of liposomal siRNA using a fluidic device and tangential flow filtration (TFF). A number of studies have appeared on the use of fluidic devices for preparing and purifying liposomes, but no systematic information regarding appropriate membrane type of commercially available apparatus is available. The findings reported herein indicate that, under optimized conditions, a microfluidic device and TFF can be used to produce siRNA lipid nanoparticles with the same characteristics as traditional ones'. The in vivo silencing efficiency of these lipid nanoparticles in the liver was comparable to laboratory-produced nanoparticles. In addition, con-focal laser scanning microscopy analyses revealed that they accumulated in the liver accumulation at the same levels as particles produced by batch-type and continuous-type procedures. This methodology has the potential to contribute to the advancement of this process from basic research to clinical studies of liposomal DDS.