Sustained release of complexed and naked DNA from polymer films.

Controlled release studies of DNA from polymers have been limited, with most studies concentrating on microsphere formulations. This report details a study done on the release and transfection efficiencies of pDNA-lipofectamine complex (lipoplex), from selected polymeric films in which it was dispersed; the release and transfection efficiency was compared with that of naked pDNA. A biodegradable and a biostable polymer were compared. A sustained release profile was obtained from both the polymeric films. For the release of pDNA (naked DNA), a burst effect was always seen, and was suppressed using additives; for complexed pDNA (lipoplex), the release was slow, but could be accelerated using additives. The compositions of the released lipoplexes were also quantified in terms of the fraction that was complexed. In addition, the transfection efficiency of the released complexes and of the naked pDNA was determined in vitro using COS 7 cells. The results also demonstrated that bioactivity of the released complexed pDNA was superior to that of the released naked DNA. Such formulations may be useful for local sustained delivery of lipoplexes from implanted films.