After animals are administered with the radiolabeled test articles, the following studies will be conducted to:
1) Investigate the recovery rate and mass balance of the total radioactivity in the urine and feces,
2) Investigate the tissue distribution of the total radioactivity,
3) Determine the concentration-time profiles of the plasma/blood,
4) Identify the metabolite profiles and major metabolites of plasma, bile, urine, and feces collected from animals (refer to the metabolite profiling and identification studies).
Various species (mouse, rat, minipig, dog, and monkey) models can be provided for in vivo studies with radiolabeled test articles.
Animals will be transferred to the corresponding metabolic cages. Urine, feces, bile, plasma, and tissue samples will be collected at specific time points after administration. The total radioactivity in the various matriceswill be analyzed by liquid scintillation counter to investigate the pharmacokinetics of radiolabeled test articles.
The types of test articles include but are not limited to small molecules, peptides, ADC, and oligonucleotides.
If the recovery of the total radioactivity in mass balance is less than 90%, it is recommended to conduct a 14CO2 collection study.
The animals will be placed in sealed glass cages and the air flow in the cages guided by an air pump. After passing through the CO2 absorber, the total radioactive recovery of 14CO2-related gas from an absorber will be analyzed and calculated to determine whether the test articles can be excreted via the respiratory route.
14CO2 metabolic cage