Application of a tiered approach to the validation of accelerator MS assays

Since its introduction into the drug-development arena, accelerator mass spectrometry (coupled with liquid chromatography fractionation) has been used to support a variety of study types. The uses to which the technique has been put include parent and/or metabolite quantification in pharmacokinetic studies, total radioactivity measurement in adsorption, metabolism and excretion studies, and quantitative metabolite profiling. A tiered approach has been applied to the verification of accelerator mass spectrometry assays, dependant on in which type of study and at what stage of drug development they are used. As accelerator mass spectrometry is an absolute detector that can quantify without the use of analyte-related standards, the specific assay verification requirements differ from those for LC–MS/MS assays. This article describes when screening, qualified and validated assay verification procedures should be applied, and suggests what parameters should be assessed in each case.

The early estimation of circulating drug metabolites in humans

INTRODUCTION

An evolution in bioanalytical methodologies to identify and quantify drug metabolites has led to a wealth of biotransformation information during preclinical and early clinical testing phases. However, this abundance of metabolism data has not clarified how to select the most important circulating human metabolites for safety assessment. Consequently, more stringent regulatory expectations for a comprehensive approach to human metabolism have led pharmaceutical sponsors to employ a variety of novel methods to estimate circulating drug metabolites in humans and animals.

AREAS COVERED

This review provides context for 'why' human circulating metabolites must be qualified for safety in animals. A detailed overview is also presented concerning 'where,' 'how' and 'when' to conduct these assessments during drug development.

EXPERT OPINION

A human metabolite qualification strategy is now a required element of the drug safety package submitted with a new drug application (NDA). The important question is whether or not this additional information, about metabolite safety, is making human drugs any safer. Currently, this is a debatable issue, especially because stand-alone metabolite testing is fraught with its own challenges. As drug development moves into the twenty-first century, there is a pressing need for more sophisticated methodologies to address human drug and metabolite safety.

Conference Report: The 19th International Reid Bioanalytical Forum

The 19th International Reid Bioanalytical Forum was attended by over 120 participants. The Forum divided into approximately eight broad topics, although not always in the same session. The meeting commenced with a discussion on metabolites in safety testing, with emphasis on enabling technologies and philosophies. This was followed by a variety of regulatory-based issues initiated by Brian Booth of the US FDA. The next day started with a review of developing technologies in LC–MS and some anecdotal troubleshooting experiences. Interspersed among the sessions were experiences with bioanalysis in the discovery environment, biomarker-based topics and the rapidly developing field of the quantitation of proteins and peptides using LC–MS. The meeting finished with the best-attended session of the Forum on developing trends in using dried blood spots.