Stabilization of polymer-based gene delivery systems

To preserve the size and transfection potential of polymer-plasmid complexe s, freeze-drying and freeze-thawing were used for stabilization of these co mplexes. The concentration of the sugars is an important factor affecting b oth the size and transfection capability of the complexes after freeze-dryi ng and freeze-thawing. However, the type of lyoprotectant (sugar) used is o f minor importance. It is also shown that when damage to polymer-plasmid co mplexes occurs, it results from the drying process but is not due to the fr eezing step. (C) 1999 Elsevier Science B.V. All rights reserved.