Metabolite profiling and identification studies in whole blood or plasma of animal can provide information on exposure of drug-related components (and/or) the metabolite profiles of drugs. This can be used to evaluate the effect on bioavailability arising from absorption or metabolism and to guide subsequent structural optimization and formulation adjustment.
The metabolite profiling and identification study in animal excreta (including bile, urine, and feces) can provide information on the drug's metabolic and clearance pathways. The correlation between in vitro and in vivo metabolism of the drug can be analyzed when compared with results from in vitro metabolism studies in liver microsomes and hepatocytes, supporting the prediction of metabolism and disposition in human based on in vitro metabolic pathways.
The first-in-human (FIH) studies will provide the earliest information of drug exposure to human. Also, metabolite profiles in human excreta, together with mass balance data, can provide information on major metabolic and clearance pathways of drugs in human. The metabolite profiling and identification of human plasma from the multiple ascending dose (MAD) experiment can determine how many metabolites are in the plasma and identify their structures and relative abundances. Further study is conducted to evaluate whether major human plasma metabolites are present in animal circulation with exposure levels equal to or higher than those in human, which is very important to ensure toxicity of major human plasma is tested in the toxicological species.
The in vivo MetID platform in WuXi AppTec uses ultra-high performance liquid chromatography (UPLC) coupled with photodiode array detector (PDA) and high-resolution mass spectrometry (HRMS) such as Q-TOF and Orbitrap to acquire accurate mass spectral data efficiently. Using HRMS and multiple data processing tools, MetID results are generated with great confidence, which are used to support safety assessment, clinical studies, and regulatory submissions. The established in vivo MetID platform has performed metabolite profiling and identification of lead compounds and drug candidates with a variety of structures, including but not limited to conventional small molecules, high-polar and non-polar small molecules, natural products, nucleotides, Proteolysis-Targeting Chimeras(PROTACs), polysaccharides, peptides, ADCs, PDCs, and oligonucleotides. Sample matrices include whole blood, plasma, urine, feces, bile, and tissues.
After the drug enters the human body, the produced metabolites are all exogenous substances for the human body. When the exposure to a metabolite at a steady state exceeds 10% of the total exposures of all drug-related components in human, the safety of this metabolite should be evaluated in toxicological studies. Drug metabolites in plasma can be searched and identified, and relative abundances of the detected metabolites obtained using high-resolution mass spectrometry combined with relevant data processing software. For major metabolites, further comparison of its exposure to toxicological species should be determined after multiple-dosed toxicological species. Results from the study can ensure if the selected toxicological species are appropriate.