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AAPS PharmSciTech. 2005 June; 6(2): E198–E201.
Published online 2005 September 30. doi:  10.1208/pt060229
PMCID: PMC2750532

Monitoring the fluidized bed granulation process based onS-statistic analysis of a pressure time series


Pressure fluctuation measurements collected during the fluidized bed granulation of pharmaceutical granule have been analyzed using the attractor comparison technique denoted as theS-statistic. Divergence of the bed state from the reference during granulation is followed by a return to a condition statistically similar to the original state of the dry fluidized ingredients on drying. This suggests insensitivity of theS-statistic technique to the changes in particle size distribution occurring during the granulation process. Consequently, the monitoring of pressure fluctuations alone may provide an easily implemented technique for the tracking of granule moisture and process end-point determination.

Key words: fluidized bed, granulation, S-statistic, hydrodynamics, chaos, pressure fluctuations

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Selected References

These references are in PubMed. This may not be the complete list of references from this article.
1. Kawai S. Granulation and drying of powdery or liquid materials by fluidized-bed technology. Drying Tech. 1993;11:719–731. doi: 10.1080/07373939308916860. [Cross Ref]
2. Watano S, Takashima H, Miyanami K. Control of moisture content in fluidized bed granulation by neural network. J Chem Eng Japan. 1997;30:223–229. doi: 10.1252/jcej.30.223. [Cross Ref]
3. Gore AY, McFarland DW, Batuyios NH. Fluid-bed granulation: factors affecting the process in a laboratory development and production scale-up. Pharm Tech. 1985;9:114–122.
4. Rantanen J, Jørgensen A, Räsänen E, et al. Process analysis of fluidized bed granulation. AAPS Pharmsci Tech. 2001;2:E21–E21. doi: 10.1208/pt020421. [PMC free article] [PubMed] [Cross Ref]
5. van der Schaaf J, Schouten JC, van den Bleek CM. Origin, propagation and attenuation of pressure waves in gas-solid fluidized beds. Powder Tech. 1998;95:220–233. doi: 10.1016/S0032-5910(97)03341-X. [Cross Ref]
6. Chong YO, O’Dea DP, White ET, Lee PL, Leung LS. Control of the quality of fluidization in a tall bed using the variance of pressure fluctuations. Powder Tech. 1987;53:237–246. doi: 10.1016/0032-5910(87)80097-9. [Cross Ref]
7. Kage H, Iwasaki N, Yamaguchi H, Matsuno Y. Frequency analysis of pressure fluctuation in fluidized bed plenum. J Chem Eng Japan. 1991;24:76–81. doi: 10.1252/jcej.24.76. [Cross Ref]
8. Bai D, Bi HT, Grace JR. Chaotic behavior of fluidized beds based on pressure and voidage fluctuations. AIChE. J. 1997;43:1357–1361. doi: 10.1002/aic.690430525. [Cross Ref]
9. van Ommen R. Monitoring Fluidized Bed Hydrodynamics. Delft, The Netherlands: Technical University of Delft; 2001.
10. Chaplin G, Pugsley T, Winters C. Application of chaos analysis to pressure fluctuation data from a fluidized bed dryer containing pharmaceutical granule. Powder Tech. 2004;142:110–120. doi: 10.1016/j.powtec.2004.05.001. [Cross Ref]
11. Chaplin G, Pugsley T, Winters C. Application of chaos analysis to fluidized bed drying of pharmaceutical granule. In: Arena U, Chirone R, Miccio M, Salatino P, editors. Fluidization XI. New York: Engineering Foundation; 2004. pp. 419–426.
12. Diks C, van Zwet WR, Takens F, DeGoede J. Detecting differences between delay vector distributions. Phys. Rev E. 1996;53:2169–2176. doi: 10.1103/PhysRevE.53.2169. [PubMed] [Cross Ref]
13. van Ommen JC, Coppens MC, van Den Bleek CM. Early warning of agglomeration in fluidized beds by attractor comparison. AIChe J. 2000;46:2183–2197. doi: 10.1002/aic.690461111. [Cross Ref]

Articles from AAPS PharmSciTech are provided here courtesy of American Association of Pharmaceutical Scientists