Influence of formulation parameters on the characteristics of poly(d,l-lactide-co-glycolide) microspheres containing poly(l-lysine) complexed plasmid DNA

Effect of Surfactants on Plasmid DNA Stability and Release from Poly (D,L-lactide-co-glycolide) Microspheres

“…All microspheres exhibited varying amount of burst release in the first 5 h, followed by sustained release phase over the 4 weeks. As repeatedly reported, the burst release was suggested to be due to the pDNA located near the surface [12]. Only F4 (Span-Tween blend of HLB 10) released more than 90 % over the 4 weeks with more than 50 % burst release in the first 5 h. Fig 5 shows the stability of pDNA during the release study using agarose gel electrophoresis to detect the presence of pDNA and its conformation.…”

Poly (D, L-lactide-co-glycolide)/DNA microspheres to facilitate prolonged transgene expression in airway epithelium in vitro, ex vivo and in vivo

“…18 Secondly, formulation of the microparticles is relatively simple and results in high efficiency of DNA encapsulation (B50%). Third, the preparation is stable 5 and suitable for resuspension at concentrations that allow for administration of small volumes in vivo. This is in contrast to preparation of gelatin-DNA nanoparticles, 4 which have lower encapsulation efficiency and where the final concentration of the suspension requires administration of large volumes to achieve optimal cDNA transfer (data not shown).…”

“…5 Briefly, pDNA was complexed with PLL by rapid mixing of pDNA in Tris-EDTA buffer with PLL (pDNA/PLL ratio 1:0.3). The microspheres were prepared by dispersing an aqueous solution of pDNA/PLL complex into a 6% (w/w) solution of PLG in methylene chloride made up in a glass container and vortexed for 2 min.…”

“…DNA has also been formulated with the synthetic, biodegradable polymer, poly(lactide-co-glycolide) (PLG) to generate microparticles capable of sustained gene delivery and expression. [5][6][7] PLG, which has a history of safe application in humans, 8 has been used extensively in the development of vaccine technology, [9][10][11] and may be loaded with biologically active molecules of widely different molecular size including insulin, 12 prolidase, 13 camptothesin 14 and rhVEGF. 15 pDNA encapsulated in PLG remains stable, and protected from enzymatic degradation.…”

“…15 pDNA encapsulated in PLG remains stable, and protected from enzymatic degradation. 5,16 In this study, we have explored the potential use of PLG microspheres for sustained gene delivery and expression in airway epithelium, with a view to further application for cystic fibrosis gene therapy. Following formulation and characterization of the microspheres, gene transfer efficiency and duration of transgene expression have been tested in vitro on both non-CF and CF cell lines, ex vivo in a model using native sheep trachea and finally in vivo by instillation into the lungs of Balb/C mice.…”