Pharmaceutical Research

, 26:512 | Cite as

Development of a Novel Method for Formulating Stable siRNA-Loaded Lipid Particles for In vivo Use

  • Sherry Y. Wu
  • Lisa N. Putral
  • Mingtao Liang
  • Hsin-I. Chang
  • Nigel M. Davies
  • Nigel A. J. McMillan
Research Paper



A simple yet novel method was developed to prepare stable PEGylated siRNA-loaded lipid particles which are suitable for in vivo use.


PEGylated siRNA-loaded lipid particles were formulated by hydration of a freeze-dried matrix. The effect of various formulation parameters on the size and homogeneity of resulting particles was studied. Particles prepared using this method were compared to those prepared using an established post-insertion procedure for the entrapment efficiency, stability, in vitro biological activity as well as in vivo biodistribution.


Using this hydration method, a particle size of less than 200 nm can be obtained with high siRNA entrapment efficiency (>90%) and high gene-silencing efficiency. Following intravenous administration into mice, these particles achieved a similar degree of accumulation in subcutaneous tumours but displayed less liver uptake compared to the post-insertion formulations. Importantly, in contrast to post-insertion preparations, particles made by hydration method retained 100% of their gene-silencing efficiency after storage at room temperature for 1 month.


This paper describes a simple method of formulating PEGylated siRNA-loaded lipid particles. Given the ease of preparation, long term stability and favourable characteristics for in vivo delivery, our work represents an advance in lipid formulation of siRNA for in vivo use.


cancer liposomes PEGylation siRNA systemic gene delivery 



Base pair






Distilled water


1,1′-Dioctadecyl-3,3,3′,3′-tetramethylindotricarbocyanine iodide


Dulbecco’s modified Eagle medium


Deoxyribonucleic acid




Dioleoyl trimethylammonium propane


Double-stranded DNA


Double-stranded RNA


Ethylenediaminetetraacetic acid


Fluorescence activated cell sorting


Fetal bovine serum


Green fluorescence protein


Hydration of freeze-dried matrix




Lipid particle


Messenger RNA






Phosphate buffered saline


Polyethylene glycol




Reticuloendothelial system


Ribonucleic acid


RNA interference


Room temperature


Standard deviation


Small interfering RNA





This work was funded by National Health and Medical Research Council (NHMRC) and we thank Australian Institute for Bioengineering & Nanotechnology for providing Malvern Nano Zetasizer for this study. The authors also gratefully acknowledge Dr Montree Jaturanpinyo for technical assistance and Dr Wenyi Gu for providing cell lines.


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Copyright information

© Springer Science+Business Media, LLC 2008

Authors and Affiliations

  • Sherry Y. Wu
    • 1
    • 2
  • Lisa N. Putral
    • 1
  • Mingtao Liang
    • 2
  • Hsin-I. Chang
    • 2
  • Nigel M. Davies
    • 2
  • Nigel A. J. McMillan
    • 1
  1. 1.Diamantina Institute for Cancer, Immunology and Metabolic MedicineUniversity of Queensland, Princess Alexandra HospitalBurandaAustralia
  2. 2.School of PharmacyUniversity of QueenslandBrisbaneAustralia

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