» Urea C 14 Capsules contain ¹⁴CH₄N₂O in which a portion of the molecules are labeled with radioactive ¹⁴C to provide 0.04 MBq (or 1 µCi) of radioactivity per capsule. It contains not less than 90.0 percent and not more than 110.0 percent of the labeled amount of ¹⁴C expressed as MBq (or µCi).