Could traditional mass-balance studies in the 'twilight zone be improved by means of accelerator MS measurements?

摘要

The main objective of a traditional mass-balance study is to measure the difference between the excreted fraction and the administered amount of a drug. The second objective is to determine the routes of excretion. A standard procedure is to administer a single dose of the drug molecule labeled with~( 14)C and to collect all urine and feces excreted for a certain period of time, which should correspond to about five half-lives of the drug in order to account for the major fraction of~( 14)C. The excreted amounts of ~(14)C in the urine and feces samples are then measured with a scintillate detector. In theory, this seems to be a fairly simple and straightforward approach. In practice however, there are several obstacles to overcome.