Statistical differences in this measurement were evaluated by paired, two-tailed t-test across the four animals used for lung deposition imaging. 3. Results 3.1. Precisely Engineered Particles Containing Pharmaceutically Relevant Components To illustrate the delivery of relevant therapeutic compounds to the respiratory tract, we fabricated particles with independent control of particle size, shape, and composition. An array of SEM micrographs is shown in Figure 2 highlighting PRINT’s versatility: BSA/lactose blend 200 × 200nm cylinders (Figure 2(a)); IgG/lactose blend 10μm “pollen” (Figure 2(b)); poly-lactic-co-glycolic Inhibitors,research,lifescience,medical acid (PLGA, Mw 30K) 3μm cylinders (Figure 2(c)); itraconazole (marketed

as Sporanox for treatment of fungal infection) molded

into 1.5μm, 3μm, and 6μm torus particles (Figures 2(d)–2(f)); 1.5μm torus particles comprised of pharmaceutically relevant compounds including zanamivir (marketed as Relenza for treatment of influenza) Inhibitors,research,lifescience,medical (Figure 2(g)); bovine DNase (recombinant human DNase Inhibitors,research,lifescience,medical is marketed as Pulmozyme for treatment of cystic fibrosis) (Figure 2(h)); siRNA (Dharmacon) (Figure 2(i)). The “pollen” shape in Figure 2(b) is a biomimetic design, based on the shape of the pollen Eperua schomburgkiana. Figure 2 SEM micrographs of diverse PRINT aerosols. (a) BSA/Lactose 200 × 200nm cylinders; (b) IgG/Lactose10μm pollen; (c) 30K PLGA 3μm cylinders; (d) itraconazole 1.5μm torus; (e) itraconazole … In order to confirm that the PRINT particle fabrication process used to generate engineered aerosols did not alter the chemical structure of pharmaceutical compounds, analytical tests were performed to determine the compound integrity

following fabrication as compared to the unprocessed or reference Inhibitors,research,lifescience,medical compound. Purity of compounds in PRINT particles GABA activity relative to unprocessed or reference compound was measured to be 99.6% for itraconazole (RP-HPLC), 100% for zanamivir (HILIC-HPLC), 99.2% for siRNA (SAX-HPLC), and 99.0% for DNase (SEC). Additionally, Inhibitors,research,lifescience,medical IC50 in DNA-Methyl Green assay yielded Carnitine dehydrogenase DNase IC50 values for reference DNase (Worthington) and PRINT-DNase of 26.5 and 18.8Kunitz units/mL, respectively, indicating that PRINT particle fabrication does not alter DNase bioactivity. 3.2. Aerodynamic Characteristics of PRINT Aerosols Physical characterization of PRINT aerosols confirmed the ability to produce highly dispersible aerosols with controllable and narrow aerodynamic size distributions. Figure 3(a) demonstrates the capability to tune particle aerodynamic size on the basis of particle design. We fabricated torus particles with geometric sizes 1.5μm, 3μm, and 6μm torus and measured their aerodynamic characteristics using a time-of-flight aerodynamic particle sizer (APS). For these particles, porogen was added to the formulation, then subsequently removed to produce porous particles.