VALIDATION OF EXCEL SPREADSHEET
HEIKO BRUNNER, PH.D.
Eli Lilly Germany
18.1 INTRODUCTION Excel is one of the most commonly used computer programs to perform automatic or semiautomatic calculation and visualization of data. Other applications include, but are not limited to, testing of acceptance criteria and using spreadsheets as a view tool for databases. The use of Excel spreadsheetsin a regulated environment (cGXP = GMP, GLP, GCP) has to be controlled and validated. Also, periodic revalidation after deﬁned intervals or changes has to be performed. This is consistent with EC guides on Good Manufacturing Practice (chapter 6.7, “Documentation”  and chapter 6.16, “Testing” ) and the FDA 21 CFR Part 11  electronic records and electronic signatures regulation. A systematicapproach in the generation and validation of the spreadsheets application will be required to ensure the validity of the data. Spreadsheets that can be used for multiple purposes or that can generate multiple types of information are sometimes preferred over single-purpose spreadsheets. An example is a spreadsheet designed to work for different products or a spreadsheet designed to producemultiple result sets from a single data set [e.g., a content uniformity evaluation according to European Pharmacopoeia (Pharm. Eur.), United States Pharmacopoeia (USP), and Japanese Pharmacopoeia (JP) (prior to ICH harmonization)].
Analytical Method Validation and Instrument Performance Veriﬁcation, Edited by Chung Chow Chan, Herman Lam, Y. C. Lee, and Xue-Ming Zhang ISBN 0-471-25953-5 Copyright 2004John Wiley & Sons, Inc.
VALIDATION OF EXCEL SPREADSHEET
There is a negative side to highly ﬂexible spreadsheets. Development and validation of such spreadsheets require substantial time. A spreadsheet designed for a single task may not be as powerful as a more ﬂexible spreadsheet, but it is much easier to create and validate. In this chapter we focus on the validation ofspreadsheets generated with Excel but do not cover spreadsheets generated with other software programs. Nevertheless, general strategies and procedures will be applicable for the validation of spreadsheets generated with other programs. Whenever a standard calculation has to be repeated over a long period of time, the generation of a validated spreadsheet should be considered. Validation ofspreadsheets can be time- and resource-intensive. Therefore, it has to be decided if a validated Excel spreadsheet is the solution of choice. Beside the actual validation of each spreadsheet, a procedure has to be established to handle and work with the spreadsheet. GXP-related questions to address include the use of secure data storage locations, missing ER/ES compliance, and audit trail in Excel. Theseareas are as important as the validation itself and will require resources. 18.2 SCOPE OF CHAPTER Since Excel is a powerful tool used widely for many different purposes with many options; not all options can be discussed in this chapter. The focus of the chapter is on manually self-created spreadsheets for data calculation and checks against acceptance criteria (logical operations). Excelspreadsheets that are used with other electronic systems for automatic data or information entry, for further operations, or used as a “view tool” for databases are not within the scope of this chapter. Nevertheless, these types of spreadsheets are viewed as a “normal” spreadsheet with automatic entry, and validation, including validation of the interface, will be included to cover this item. In thischapter we provide guidance in validation and revalidation of Excel spreadsheets and information about managing validated spreadsheets. During the development (design) of a spreadsheet, a clear purpose and data structure are very important for the validation and subsequent application. The design of the spreadsheet should be well ordered, whether data are populated in the spreadsheet automatically by...