Within
this work, 12 different pharmaceutical compounds were analyzed
by the single-frequency ultrasound measurement technique for its applicability
to determine concentrations, as an important process parameter during
crystallization processes, or to determine the metastable zone widths,
as an important precondition for the development of crystallization
processes. The results were compared to the applicability of inorganic
and nonpharmaceutical compounds that have been discussed in the literature.
It was found that according to the change of ultrasound velocity and
adiabatic compressibility, a grouping of compounds can be derived.
From this grouping it can be concluded that some organic compounds
and especially inorganic compounds show an excellent applicability
for concentration determination, while the application for pharmaceutical
compounds is most often limited. Furthermore, a cost- and time-efficient
possibility is shown for the integration of this technique in a pilot-plant-scale
setup. A direct transferability of calibration models developed at
the laboratory scale was found as long as the influence of undissolved
air/gas was low in the pilot-plant setup
