AAPS PharmSciTech

, 20:157 | Cite as

Feedforward and Feedback Control of a Pharmaceutical Coating Process

  • Yuxiang Zhao
  • James K. Drennen
  • Shikhar Mohan
  • Suyang Wu
  • Carl A. AndersonEmail author
Research Article Theme: Team Science and Education for Pharmaceuticals: the NIPTE Model
Part of the following topical collections:
  1. Theme: Team Science and Education for Pharmaceuticals: the NIPTE Model


This work demonstrates the use of a combination of feedforward and feedback loops to control the controlled release coating of theophylline granules. Feedforward models are based on the size distribution of incoming granules and are used to set values for the airflow in the fluid bed processor and the target coat weight to be applied to the granules. The target coat weight of the granules is controlled by a feedback loop using NIR spectroscopy to monitor the progress of the process. By combining feedforward and feedback loops, significant variation in the size distributions and ambient conditions were accommodated in the fluid bed coating of the granules and a desired dissolution profile was achieved. The feedforward component of the control system was specifically tested by comparing the performance of the control system with and without this element by Monte Carlo simulation.


feedforward feedback process control granule coating near-infrared 



We would like to thank Dr. Carl Wassgren and Dr. Dhananjay A Pai from Purdue University for the production of the theophylline granules.

Funding Information

The National Institute for Pharmaceutical Technology and Education (NIPTE) and the U.S. Food and Drug Administration (FDA) provided funds for this research. This study was funded by the FDA Grant to NIPTE titled “The Critical Path Manufacturing Sector Research Initiative (U01)”; Grant# 5U01FD004275.


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Copyright information

© American Association of Pharmaceutical Scientists 2019

Authors and Affiliations

  • Yuxiang Zhao
    • 1
  • James K. Drennen
    • 1
    • 2
  • Shikhar Mohan
    • 1
  • Suyang Wu
    • 1
  • Carl A. Anderson
    • 1
    • 2
    Email author
  1. 1.Duquesne University Graduate School of Pharmaceutical SciencesPittsburghUSA
  2. 2.Duquesne University Center for Pharmaceutical TechnologyPittsburghUSA

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