Carbon-14 radiolabelling and tissue distribution evaluation of a potential anti-TB compound.

This paper describes a five-step synthesis of a carbon-14-labelled pyrazole compound (11). A total of 2.96MBq of 11 was obtained with the specific activity of 2242.4MBq/mmol. The radiochemical purity was >99%, and the overall radiochemical yield was 60% based on the [C-14(6)] 4-bromoaniline starting material. Biodistribution results showed that the radiotracer (administrated orally) has a high accumulation in the small intestine, large intestine and liver of both non-infected and tuberculosis (TB)-infected mice. Therefore, this suggests that compound 11 undergoes hepatobiliary clearance. The compound under investigation has been found to be slowly released from the liver between 2 and 8h. The study revealed that 11 has no affinity for TB cells.