Fig. 2
Therapeutic drug monitoring on Cap and its metabolites. a A simplified metabolic pathway of Cap. Metabolites and enzymes are indicated in black and red, respectively. Plasma concentrations of Cap (b) and its metabolites 5′-dFCR (c), 5′-dFUR (d), 5-FU (e), and FUH2 (f) were measured before and 1–4 h after the administration of Cap. The concentrations are presented as the mean ± SEM. Abbreviations: Cap, capecitabine; 5′-dFCR, 5′-deoxy-5-fluorocytidine; 5′-dFUR, doxifluridine; 5-FU, 5-fluorouracil; FUH2, 5-fluoro-5,6-dihydrouracil; CES, carboxylesterase; CDA, cytidine deaminase; TYMP, thymidine phosphorylase; and DPYD, dihydropyrimidine dehydrogenase