Unbiased Scanning Method and Data Banking Approach Using Ultra-High Performance Liquid Chromatography Coupled with High-Resolution Mass Spectrometry for Quantitative Comparison of Metabolite Exposure in Plasma across Species Analyzed at Different Dates

Biosynthesis using cytochrome P450 enzymes: Focus on synthesis of drug metabolites

While modern synthetic chemistry provides the ability to synthesize an incredible variety of new structures, the natural world provides unmatched chemical diversity. This diversity can be employed in the drug discovery process either through isolation of an organic molecule from a biological source as a drug candidate, usually referred to as natural product chemistry, or by providing enzymes that are capable to performing chemistry not available through synthetic chemistry approaches. Natural or engineered enzymes can be used in candidate discovery to generate chemical diversity in conjunction with synthetic efforts. As a candidate progresses into develop there is often a need to characterize metabolites, thus a need for metabolite standard synthesis. Metabolite synthesis is best accomplished with a flexible application of both chemical and biosynthetic approaches. This overview of the use of biosynthesis to aid in the drug discovery and development process will cover multiple methodologies with a focus on the use of microbes as a flexible and cost-effective resource.

Handling unstable analytes: literature review and expert panel survey by Japan Bioanalysis Forum Discussion Group

Analyzing unstable small molecule drugs and metabolites in blood continues to be challenging for bioanalysis. Although scientific countermeasures such as immediate cooling, immediate freezing, addition of enzyme inhibitors, pH adjustment, dried blood spot or derivatization have been developed, selecting the best practices has become an issue in the pharmaceutical industry as the number of drugs with such problems is increasing, even for generic drugs. In this study, we conducted a comprehensive literature review and a questionnaire survey to determine a suitable practice for evaluating instability and implementing countermeasures. Three areas of focus, matrix selection, effect of hemolysis and selection of esterase inhibitors, are discussed.