Biomedical Engineering Reference
In-Depth Information
homogenisation process [15]. Process parameters mixing speed and high con-
centrations were varied according to an experimental design and a principal
component regression model was developed for API concentration. Real-time
monitoring of API concentration and endpoint determination was reported
successful and the prospect of improved process eciency and understand-
ing was pointed out. Jayawickrama et al. reported on four different in-line
Raman applications [48]. They demonstrated non-contact monitoring of gran-
ule blend homogeneity, non-contact monitoring of polymorph transformation
of API during high-shear wet granulation, non-contact monitoring of API dis-
tribution as a solid suspension in a molten excipient solution and immersion
probe monitoring of API solubilisation in a molten excipient. Wikstrom et al.
reported on the use of in situ Raman spectroscopy for high-shear wet granu-
lation monitoring of the transition of anhydrous to monohydrate theophylline
using an immersion probe setup [49]. In Fig. 10.7, the transition from an-
hydrous to monohydrate theophylline is shown. Later, they compared three
different probe designs including a large spot probe instrument [50]. They
determined effective sampling volumes and could show the significant benefit
of going from a point focus to an extended large spot focus. Hausman et al.
demonstrated the use of in-line Raman spectroscopy for monitoring of drug hy-
dration state during fluid bed drying [14]. The relation of risedronate sodium
hydration state and physical parameters of the tablets was investigated and
the final granulation moisture was identified as a critical parameter. Walker
Fig. 10.7.
Three-dimensional plot of wet granulation theophylline process. The
plot shows transformation from anhydrous to monohydrate form [49]. Copyright by
Wiley Liss Inc. and the American Pharmacists Association
Search WWH ::
Custom Search