Feedforward and Feedback Control of a Pharmaceutical Coating Process
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.
Keywordsfeedforward 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.
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.
- 2.Corripio AB. Tuning of industrial control systems: Isa; 2000.Google Scholar
- 3.Johansson B. Feedforward control in dynamic situations. Sweden: Linköping University; 2003.Google Scholar
- 9.Mota J. Matrix- and reservoir- type oral multiparticulate drug delivery systems. Berlin: Freien Universität Berlin; 2010.Google Scholar
- 12.The United States Pharmacopeia. Theophylline extended-release capsules. Pharm Forum. 2006;31, 185(1).Google Scholar
- 13.Carlin B, Yang S, Li JX, Felton LA. Pseudolatex dispersions for controlled drug delivery. In: Aqueous polymeric coatings for pharmaceutical dosage forms. 4th ed. Boca Raton: CRC Press; 2016. p. 11–46.Google Scholar
- 14.Farooq M, Shoaib MH, Yousuf RI, Qazi F, Hanif M. Development of extended release loxoprofen sodium multiparticulates using different hydrophobic polymers. Polym Bull. 2018:1–22.Google Scholar
- 17.ICH Guideline. Pharmaceutical development. Q8 (2R). As revised in August. 2009.Google Scholar