Biodistribution studies of polymeric nanoparticles for drug delivery in mice.

Abstract Duchenne muscular dystrophy (DMD) is a severe hereditary neuromuscular disorder caused by mutations in the dystrophin gene. Antisense-mediated targeted exon skipping has been shown to restore dystrophin expression both in DMD patients and in the mdx mouse, the murine model of DMD, but the ineffective delivery of these molecules limits their therapeutic use. We demonstrated that PMMA/N-isopropil-acrylamide (ZM2) nanoparticles (NPs), administered both intraperitoneally and orally, were able to deliver 2'OMePS antisense inducing various extents of dystrophin restoration in the mdx mice. Defining NP biodistribution is crucial to improve effects on target and dose regimens; thus, we performed in vivo studies of novel ZM4 NPs. ZM4 are conjugated with NIR fluorophores as optical probes suitable for studies on the Odyssey Imaging System. Our results indicate that NPs are widely distributed in all body muscles, including skeletal muscles and heart, suggesting that these vehicles are appropriate to deliver antisense oligonucleotides for targeting striated muscles in the DMD animal model, thus opening new horizons for Duchenne therapy.