Nanoscale Res Lett (2009) 4:254–261 to determine the dose-dependent delivery to the lungs. Different concentrations of the ﬂuticasone nanosuspension were nebulized. Conscious mice were loaded into restraining tubes, which left their naris exposed. The tubes were then attached to a Jaeger-NYU Nose-Only Directed Flow Inhalation Exposure System (12 port) via the nose cone, so that the naris of the animals were directly in front of a designated delivery vent. The dosing duration for animals in all aerosol delivery groups was kept to 10 min and sacriﬁced according to the general in vivo procedure. Comparison of the efﬁciency of different dosing tech- niques For comparison studies, the efﬁciency of two nebulizers, PARI LC and BANG, was compared. Unanesthetized mice were loaded into restraining tubes, which left their naris exposed. The tubes were then attached to a Jaeger-NYU Nose-Only Directed Flow Inhalation Exposure System (12 port) via the nose cone, so that the naris of the animals were directly in front of a designated delivery vent. The ﬂow rate, duration of dos- ing, dose solution concentration were optimized and adjusted according to the dosage required. The dosing duration for animals in all aerosol delivery groups was kept to 10 min and sacriﬁced according to the general in vivo procedure. 257 Results and Discussion Micronization of ﬂuticasone successfully reduced the par- ticle size of the bulk material from a mean value (D50) of 1.6 to 0.2 lm. The solid form of the micronized material was examined by PXRD and TGA/SDTA, and demonstrated no discernable change in the crystal form post the microniza- tion process. (Fig. 1). Content uniformity, potency, and homogeneity of the formulations were tested to ensure quality of test material for all studies. In general, nanosus- pension performs very well in all the tests. Both nano and regular materials were dosed as suspension in vivo. Control samples (milled vehicle) were very clean with no glass shards observed. The dissolution rate was increased by reducing the particle size and was calculated by the Noye–Whitney equation. Solubility impact was calculated by the Oswald–Freundlich equation (Log(Cs/C?) = 2aV/ (2.303RTqm) to further characterize the nanosuspension [24]. For ﬂuticasone, a slight increase of solubility was observed (from 0.7 lM to 1.1 lM) when particle size was reduced to 0.2 lm. Despite the increase of solubility, greater than 99.9% ﬂuticasone still exists as solid crystalline in nanosuspension. Thus, any particles formed from the supernatant during nebulization were ignored. Only aerosol particle from nanoparticle aggregation were considered. Fig. 1 Fluticasone PXRD patterns. Top is the post milling and bottom is the pre-milling API 123 4000 3000 ) s t n u o C ( n iL2000 1000 0 3 10 20 2-Theta - Scale 30