Pharmaceutical aspects of polymer-based non-viral gene delivery systems: experience with p(DMAEMA)-pCMV-lacZ polyplexes

Publication Type:

Journal Article


Stp Pharma Sciences, Volume 11, Number 1, pp. 11-19 (2001)




gene delivery; cationic polymers; polyplexes; formulation; freeze-drying; stability; poly(2-(dimethylamino)ethyl methacrylate); poly(2-(dimethylamino)ethyl methacrylate)-based polyplexes; lipid-DNA complex; in-vivo; transfection efficiency; cationic polym


The cationic acid and water-soluble polymer poly(2-(dimethylamino)ethyl methacrylate), p(DMAEMA), is able to condense plasmid DNA by electrostatic interactions. The ability of the thus formed polyplexes to transfect cells greatly depends on their characteristics: small (< 0.15 m), positively charged particles showed the highest transfectivity. We therefore systematically investigated the effect of formulation parameters on the polyplex characteristics. The polymer/plasmid ratio was seen to dominate the size of the polyplexes. Furthermore, a low pH and ionic strength enhanced the formation of small-sized polyplexes, especially in the presence of sucrose. Once complexed with p(DMAEMA), linear forms of DNA showed lower transfection activities than circular topoisomers. The polyplexes preserved almost their full transfection potential after aging for 10 months at 4 and 20 degreesC, but not at 40 degreesC. After storage, conformational changes in the secondary and tertiary structure of DNA were observed. Freeze-dried polyplexes with sucrose as lyoprotectant almost fully retained their transfection efficiency, even when aged for 10 months at 40 degreesC.