Formulation of poly(D,L-lactic-co-glycolic acid) microparticles for rapid plasmid DNA delivery

An optimised water-in-oil-in-water double emulsion process for the microenc apsulation of plasmid DNA in poly(D,L-lactic-co-glycolic acid) (PLGA) was u sed to prepare microparticles from a range of different PLGA formulations. This process has been developed using pharmaceutically accepted solvents an d is potentially scaleable. Incorporation of plasmid DNA in the micropartic les of up to 11 mu g/mg was obtained and the retention of plasmid DNA integ rity was considerably greater than previously reported. Microparticle struc ture was determined, by scanning electron microscopy, to be hollow and size distribution characteristics were found to be independent of polymer formu lation. The ability to vary the plasmid DNA release profile by changing the PLGA formulation and polymer concentration used in the encapsulation proce ss was also demonstrated. This ability to control the release profile of th e microparticles was shown to be especially important as the physical integ rity of the encapsulated plasmid DNA was found to deteriorate with extended release times in vitro. (C) 2000 Elsevier Science B.V. All rights reserved .