Application of RSD Charts for Content Uniformity Data in Continued Process Verification

Published on: 
Pharmaceutical Technology, Pharmaceutical Technology, July 2022, Volume 46, Issue 7
Pages: 44–47

This article is focused on introducing a control chart technique using relative standard deviation (RSD) statistics (i.e., RSD chart); in other words, a coefficient of variation chart for continued process verification.

Relative standard deviation (RSD) limits were used in content uniformity in the past (before 2007). From a statistical point of view, RSD is one of the only few statistics that describes the term “uniformity” best. In a simulation study conducted by the author, both acceptance value (AV) and RSD distributions have a typical relationship where it was found that AV and RSD charts, when applied for continued process verification (CPV) purpose, can be constructed concurrently on the same chart frame to demonstrate their common overlay view. While RSD calculation is much more simple, RSD charts may also be applied to confirm the validity of AV charts in CPV exercise.


Peer-reviewed research

Submitted: May 23, 2022
Accepted: June 8, 2022

About the author

Pramote Cholayudth,, is the founder and manager of PM Consult. He is an industrial pharmacist with more than 40 years of experience. He is a guest speaker on process validation to industrial pharmaceutical scientists organized by Thailand’s FDA.

Article details

Pharmaceutical Technology
Vol. 46, No. 7
July 2022
Pages: 44–47


When referring to this article, please cite it as P. Cholayudth, “Application of RSD Charts for Content Uniformity Data in Continued Process Verification,” Pharmaceutical Technology 46 (7) 44–47 (2022).