Development of novel formulations that enhance adenoviral-mediated gene expression in the lung in vitro and in vivo.

Despite remarkable progress in the development of both viral and non-viral gene delivery vectors for cystic fibrosis therapy, low efficiency of gene transfer to the airway epithelium is a major obstacle to clinical application. Here we develop formulations that enhance cellular absorption of adenoviral vectors. We selected excipients from a panel of pharmaceutically acceptable com-pounds known to enhance drug absorption. Transduction efficiency of the virus in the presence of each ingredient was assessed in vitro and in vivo. Mannitol and chitosan substantially enhanced transduction efficiency in vitro and augmented expression in vivo by 4 and 8 log units, respectively. The most successful formulation (a blend of sucrose, mannitol, and Pluronic F68) transduced 100% of an A549 cell population in vitro and produced areas of intense gene expression in both large and small airways in vivo with minimal toxicity. Dose response studies also indicate that when placed in this formulation, the viral dose can be lowered by 1/2 log while maintaining superior levels of transgene expression. This formulation also enhanced the physical stability of the virus. No significant loss in titer was detected from a lyophilized formulation after storage at 25 degrees C for 30 days.