Formulations containing poly(lactide-co-glycolide) and plasmid DNA expression vectors

DNA expression vectors have the potential to be useful therapeutics for a wide variety of applications. However, development has been hindered by the lack of systems that provide protection from nuclease-based attack, enable cell or tissue localisation, promote adequate gene expression or provide for controlled release. At least one synthetic polymer, poly(lactide-co-glycolide) (PLG), may provide benefit in this regard. This polymer has a history of safe use in humans, has been demonstrated effective as a delivery system, its use is not hindered by composition patents, and Good Manufacturing Practices grade material is readily available from commercial sources. Safety and applicability to clinical medicine have been proven by use of the polymer as a microparticle delivery vehicle for peptides (luteinizing hormone releasing hormone agonist peptides; Lupron Depot(R) [TAP Pharmaceuticals]; Zoladex(R) [AstraZeneca]) and proteins (human growth hormone recombinant protein, Nutropin Depot(R) [Genentech]). This report focuses on the expanding field of PLG-based DNA delivery and provides a review on research and clinical experience with PLG-plasmid formulations.