In addition to the 13 C CP-MAS NMR spectra we measured the T 1 and T 1⇢ relaxation times from samples of the mAb formulations (Figure ). F6 showed a slight increase of T 1 relaxation time upon heating, whereas the a) value seems almost unchanged for F7 (the results were reproducible when measuring the data twice). In contrast to the BSA results in the previous chapter, where also T 1⇢ stayed constant, the spin-lattice relaxation time decreases after heating the mAb formulations F6 and F7. As mentioned earlier, changes in T 1⇢ have previously been correlated to changes in molecular mobility by . In analogy to these results study our data indicates that the molecular mobility of the protein as well as the sugars change after heating. As discussed previously, the comparison of the relaxation times of the sugars and protein gives information about the homogeneity at different length scales (see Figure ). Based on the fact that the T 1 relaxation times in the formulations for sucrose and mAb are identical it can be concluded that the samples are homogeneously mixed at a length scale of 20 50 nm. The T 1⇢ relaxation times also indicate a homogeneous phase, except for the heated F7, that indicates a partial phase separation on the 2 5 nm scales as the relaxation time of sugar and protein values are different. It is worth noting that for F6 and F7, whilst there are no differences between sugar and protein, the relaxation times for T 1⇢ are lower after heating, which is different compared to what we observe in BSA. This can be explained by considering that a decrease of T 1 relaxations times is associated with degradation. One study has showed that a significant decrease of T 1 (from 4.2 s to 3.2 s) is connected to an increased aggregation rate (from 0 to 24 a.u.) . However, for the systems we investigated, we rather observe it with T 1⇢ . This might be linked to a change of mobility or dynamics on a <5 nm scale. Furthermore, a variable temperature study previously probed the change of that value and linked this this to different molecular mobilities . However, this was measured at multiple temperatures and not a static one. Based on the trend observed at the static condition, the change of T 1⇢ could be connected to the change in T g,↵ and this would be in correlation with the terahertz results.