Pharmaceutical Research

, Volume 16, Issue 9, pp 1417–1423

Long Term Stability of Poly((2-dimethylamino)ethyl Methacrylate)-Based Gene Delivery Systems

  • Jong-Yuh Cherng
  • Herre Talsma
  • Daan J. A. Crommelin
  • Wim E. Hennink
Article

DOI: 10.1023/A:1018907310472

Cite this article as:
Cherng, JY., Talsma, H., Crommelin, D.J.A. et al. Pharm Res (1999) 16: 1417. doi:10.1023/A:1018907310472

Abstract

Purpose. To study the stability of polymer-plasmid complexes (polyplexes) both as an aqueous dispersion and in their lyophilized form.

Methods. The characteristics of the polyplexes (size, charge and transfection potential) were monitored at different temperatures. Moreover, we studied possible changes in the secondary and tertiary structure of the plasmid by agarose gel electrophoresis and by CD spectroscopy to gain insight into the mechanism of polyplex degradation.

Results. The polyplexes preserved almost their full transfection potential after aging in an aqueous solution of 20 mM Hepes (pH 7.4) containing 10% sucrose at 4 and 20°C for 10 months. On the other hand, the polyplexes aged at 40°C were rather unstable and lost their transfection capability with a half-life of around 2 months. During storage, conformational changes in the secondary and tertiary structure of DNA were observed. When naked plasmid DNA was aged at 40°C as an aqueous solution and complexed with polymer just before the transfection experiment, a slower drop in its transfection capability was observed. The freeze-dried polyplexes using sucrose as lyoprotectant almost fully retained their transfection efficiency, even when aged at 40°C for 10 months.

Conclusions. This study provides information about polyplex stability in aqueous dispersions on storage and demonstrates that freeze-drying is an excellent method to ensure long term stability.

plasmidpoly(2-dimethylamino)ethyl methacrylatefreeze-dryinglong-term stabilitygene therapy

Copyright information

© Plenum Publishing Corporation 1999

Authors and Affiliations

  • Jong-Yuh Cherng
    • 1
  • Herre Talsma
    • 1
  • Daan J. A. Crommelin
    • 1
  • Wim E. Hennink
    • 1
  1. 1.Department of PharmaceuticsUtrecht Institute for Phamaceutical Sciences (UIPS), Utrecht UniversityUtrechtThe Netherlands