DELIVERY OF DNA-CATIONIC LIPOSOME COMPLEXES BY SMALL-PARTICLE AEROSOL

Aerosol delivery of gene therapy for treatment of lung diseases allows topical treatment of the airways with DNA concentrations not obtainab le by systemic administration. We have investigated delivery of cation ic liposomes complexed to plasmid DNA in a small particle aerosol. Pla smid cDNA-DMRIE/DOPE complexes were nebulized using either an Aerotech II or Puritan-Bennett 1600 (PB1600) nebulizer. Reservoir sampling sho wed that DNA-DMRIE/DOPE complexes were damaged to a significant degree during nebulization, such that activity of transfected gene was dimin ished, Of the nebulizers analyzed, DNA-DMRIE/DOPE complexes were more stable in the PB1600. The loss of effective transfection by DNA-DMRIE/ DOPE, as detected by decreased reporter gene activity in A549 lung cel ls, was consistent with denaturation of the DMRIE/DOPE. In contrast, n ebulized DNA-DOSPA/DOPE complexes retained complete ability to transfe ct. Adjustments to flow rate and reservoir volume of the PB1600 allowe d a longer period of delivery of active DNA-DMRIE/DOPE particles, DNA- DMRIE/DOPE was radiolabeled with Technetium-99m (Tc-99m), nebulized, a nd the output captured in either an Andersen Sampler (AS) (Andersen, 1 958) cascade impactor particle size analyzer or an all glass impinger, cDNA-cationic lipid complexes were detected in size ranges of 0,4-10 mu m, with most particles found between 1-2 mu m. Aerosol output was c onsistent from 0 to 5 min. These results show the feasibility of aeros ol delivery of DNA-cationic lipids for the purposes of gene therapy to the lung.