[13C,15N2]-5’-Deoxy-5-fluorocytidine

5’-Deoxy-5-fluorocytidine is an intermediate metabolite of Capecitabine. Capecitabine is converted by carboxylesterase to 5'-Deoxy-5-fluorocytidine in the liver, then by cytidine deaminase to 5’-Deoxy-5-fluorouridine in the liver and tumor tissues, and finally, by thymidine phosphorylase to 5-Fluorouracil in tumors. The cytotoxicity of this intermediate occurs only after conversion to 5-Fluorouracil.

Stable isotope labeled [¹³C,¹⁵N₂]-5’-Deoxy-5-fluorocytidine is intended for use as an internal standard for the quantification of 5’-Deoxy-5-fluorocytidine and 5’-Deoxy-5-fluorouradine by LC or GC-mass spectrometry.