Ligand binding assays in the 21st century laboratory: recommendations for characterization and supply of critical reagents

Abstract

Critical reagents are essential components of ligand binding assays (LBAs) and are utilized throughout the process of drug discovery, development, and post-marketing monitoring. Successful lifecycle management of LBA critical reagents minimizes assay performance problems caused by declining reagent activity and can mitigate the risk of delays during preclinical and clinical studies. Proactive reagent management assures adequate supply. It also assures that the quality of critical reagents is appropriate and consistent for the intended LBA use throughout all stages of the drug development process. This manuscript summarizes the key considerations for the generation, production, characterization, qualification, documentation, and management of critical reagents in LBAs, with recommendations for antibodies (monoclonal and polyclonal), engineered proteins, peptides, and their conjugates. Recommendations are given for each reagent type on basic and optional characterization profiles, expiration dates and storage temperatures, and investment in a knowledge database system. These recommendations represent a consensus among the authors and should be used to assist bioanalytical laboratories in the implementation of a best practices program for critical reagent life cycle management.

Fig. 1

Critical reagent life cycle management. The schematic shows critical reagent life cycle management, from initial reagent generation through repeat use and resupply cycles. Inventory information is identified by red outlined boxes. Transfer of critical reagent information to the knowledge database is depicted by dotted lines

Fig. 2

Generation and characterization of critical reagents. Purification and conjugation (dotted boxes) processes generate lot specific reagents with unique identifiers (diamond). Initial characterization of generated reagents (hatched diamonds) includes the full characterization profile, subsequent reagents (open diamonds) may undergo characterization according to the organizations practices and procedures. Bulk reagents may be manipulated further, including thawing from frozen or diluting then re-aliquoting and re-freezing. Handling manipulations are documented, and new designations may be assigned, though the original source lot number is either maintained or cross-referenced in the inventory and knowledge database