The revised general chapter Chemometric methods applied to analytical data (5.21) has been published in this quarter’s issue of Pharmeuropa (33.3), the European Pharmacopoeia (Ph. Eur.) online forum for public comment.

The chapter is an introduction to the use of chemometrics and data science techniques. Chemometrics is the application of mathematical and statistical techniques to yield chemical information from complex data. It is particularly important in the pharmaceutical industry as it transforms data in order to allow for chemical interpretations that are not evident from the raw statistics, usually achieved by applying a number of powerful multivariate analytical techniques (MVA) to develop a model to predict or quantify the property of interest for new samples or process runs. The objective of this chapter was to provide indications on good practice and requirements for the processing of analytical data.

The general chapter was first published in 2015 (Supplement 8.7), however its revision was prompted by the continuous evolution in data science techniques since the date of publication. Pharmeuropa acknowledged that data analysis is an extremely dynamic field which has led to numerous changes in the way algorithms are referenced and applied.

In light of the latest developments, Pharmeuropa have completely rewritten or updated numerous sections of the chapter and new sections/sub-sections have been introduced. The general revision includes:

• an update of Section 1: General aspects with a review of parts on Pre-processing (1.2.2.6) and Assessment and validation of chemometric methods (1.3);

• two new sub-sections on Independent component analysis (2.2) and Decision trees and random forests (2.6);

• a general review of subsections on Similarity measures (2.3), Clustering (2.5), Multiple linear regression (2.8), Principal component regression (2.9), Support vector machines for supervised classification (2.11) and Artificial neural networks (2.12);

• a new section – Section 3. Related application fields, including sub-sections on Chemometrics in chemical imaging (3.1) and Data fusion (3.2);

• an update of the Glossary and the Abbreviations.

The deadline for comments is 30 September 2021. Comments from within the member states should be sent to the responsible national pharmacopoeial authority, while comments from countries outside the Ph. Eur. Convention or from industry associations can be sent to the European Directorate for the Quality of Medicines & HealthCare (EDQM).