2. Materials and Methods
2.1. X-Ray Powder Diffraction (XRPD)
2.2. Thermal Analysis
2.3. Hot-Stage Microscopy
3. Results and Discussion
3.1. Hot-Stage Microscopy and Thermal Analysis
- Jumping (in terms of number of crystal that jumped, their frequency, or strength of the jumps) did not depend on the heating/cooling rate.
- Jumping did not depend on the size, shape, or orientation of the crystals. As expected, jumps of the smaller crystals were more forceful, whereas the more massive crystals would only slightly move or turn over to another facet.
- The number of crystals that jumped decreased drastically with consecutive heating/cooling runs. For example, if 10 crystals jumped during the first heating run, only 2–3 would jump in the second heating run.
- Crystals continued to jump sporadically when temperature was maintained for some time within the jumping temperature interval between 323 K and 333 K. Time period of jumping depended on the temperature. At 323 K, crystals continued to jump for 10 minutes, whereas the jumps ceased after 1–2 minutes at 343 K.
- No breaking or cracking of the crystals were observed during the jumping.
- Overall, the jumps of scopolamine bromide crystals were less energetic compared to the crystals of oxitropium bromide.
3.2. In Situ Variable Temperature X-ray Powder Diffraction (VT XRPD)
Conflicts of Interest
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