Figure 4.

Raman spectra of spray-dried inhalable vaccine candidates. Respective residual spectra are given underneath the given inhalable candidate sample spectra. Primarily amorphous structure is shown in all candidates, as indicated by the relatively low intensity residual spectra. The leucine-containing T20Leu formulation was the only spectrum that exhibited some crystalline peaks. Peaks shown in the residual spectrum for the T20Leu formulation suggest that the leucine component was mostly crystalline.