Pharmaceutical Research

, Volume 27, Issue 5, pp 756–766 | Cite as

Classification of Annular Bed Flow Patterns and Investigation on Their Influence on the Bottom Spray Fluid Bed Coating Process

  • Li Kun Wang
  • Paul Wan Sia Heng
  • Celine Valeria Liew
Research Paper
First Online:
Received:
Accepted:

Abstract

Purpose

This study aims to classify annular bed flow patterns in the bottom spray fluid bed coating process, study their influence on coat uniformity and investigate the feasibility of developing real-time annular bed flow pattern detection as a PAT tool.

Methods

High-speed imaging and particle image velocimetry were used to visualize annular bed flow. Color coating and subsequent tristimulus colorimetry were employed to determine influence of annular bed flow pattern on coat uniformity. Feasibility of monitoring annular bed flow pattern through an observation window was tested using miniaturized particle velocity field and time series particle velocity orientation information.

Results

Three types of annular bed flow patterns were identified. Plug flow gave the best coat uniformity followed by global and localized fluidization. Plug flow may be advantageous for high spray-rate conditions, large-scale coating and prevention of particle segregation. Plug flow could be differentiated from the other flow patterns through a simulated observation window.

Conclusion

Annular bed flow patterns were classified and found to influence particle coat uniformity noticeably. Availability of annular bed flow information for large-scale coaters would enable adjustments for process optimization. This study highlights the potential of monitoring annular bed flow pattern as a PAT tool.

KEY WORDS

annular bed flow pattern bottom spray fluid bed coating coat uniformity particle image velocimetry process analytical technology 
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Notes

ACKNOWLEGMENTS

The authors acknowledge the funding support from the National University of Singapore Academic Research Fund (R-148-000-085-112).

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Copyright information

© Springer Science+Business Media, LLC 2010

Authors and Affiliations

  • Li Kun Wang
    • 1
  • Paul Wan Sia Heng
    • 1
  • Celine Valeria Liew
    • 1
  1. 1.GEA-NUS Pharmaceutical Processing Research Laboratory, Department of PharmacyNational University of SingaporeSingaporeSingapore

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