Testing for drug-human serum albumin binding using fluorescent probes and other methods

ABSTRACT

Introduction: Drug plasma protein binding remains highly relevant to research and drug development, making the assessment and profiling of compound affinity to plasma proteins essential to drug discovery efforts. Although there are a number of fully-characterized methods, they lack the throughput to handle large numbers of compounds. As the evaluation of adsorption, distribution, metabolism, and excretion is addressed earlier in the drug development timeline, the need for higher-throughput methods has grown.

Areas Covered: This review will highlight recent developments on methods for profiling drug plasma binding, with an emphasis on fluorescent probes and emerging high-throughput methodologies.

Expert Opinion: There have been a number of high-throughput assays developed in recent years to meet the scaled up demands for compound profiling. Ultimately, the selection of assay technology relies on a number of factors, such as capabilities of the laboratory and the breadth and amount of data required. Fluorescent probe displacement assays are highly flexible and amenable to high-throughput screening, easily scaling up to handle large compound libraries. Recent developments in fluorescence technologies, such as homogenous time-resolved fluorescence and probes utilizing the aggregation-induced emission effect, have improved the sensitivity of these assays. Other technologies, such as microscale thermophoresis and quantitative structure-activity relationship modeling, are gaining popularity as alternative techniques for drug plasma protein binding characterization.

KEYWORDS:

• High-throughput screening
• human serum albumin
• plasma protein binding
• compound attrition
• fluorescent probes

Article highlights

• Drug-plasma protein binding remains relevant to both the clinic and early/late stage drug development pipelines.

• High compound attrition and failure rates remain a heavy burden on R&D portfolios, generally due to lack of efficacy or clinical safety.

• There exist numerous and well-characterized methods for profiling plasma protein binding, but there is still a need for the integration of high-throughput assay technology earlier in the pipeline.

• Fluorescent and related assays are attractive methods due to their ease of use, optimization, and adaptability to high-throughput screening.

• There exists a breadth of fluorescent probes with different excitation and emission profiles that have been characterized against human serum albumin.

• Other methodologies, such as microscale thermophoresis and quantitative structure-activity relationship (QSAR) modeling, are new trends in high-throughput analysis of drug-plasma protein binding.

This box summarizes key points contained in the article.

Declaration of interest

The authors are employees of the National Institutes of Health, part of the United States government. The authors have no other relevant affiliations or financial involvement with any organization or entity with a financial interest in or financial conflict with the subject matter or materials discussed in the manuscript apart from those disclosed.

Reviewer disclosures

Peer reviewers on this manuscript have no relevant financial or other relationships to disclose

Additional information

Funding

This manuscript was not funded.