The design and synthesis of a new tumor-selective fluoropyrimidine carbamate, capecitabine

Bioorg Med Chem. 2000 Jul;8(7):1697-706. doi: 10.1016/s0968-0896(00)00087-0.


To identify an orally available fluoropyrimidine having efficacy and safety profiles greatly improved over those of parenteral 5-fluorouracil (5-FU: 1), we designed a 5-FU prodrug that would pass intact through the intestinal mucisa and be sequentially converted to 5-FU by enzymes that are highly expressed in the human liver and then in tumors. Among various N4-substituted 5'-deoxy-5-fluorocytidine derivatives, a series of N4-alkoxycarbonyl derivatives were hydrolyzed to 5'-deoxy-5-fluorocytidine (5'-DFCR: 8) specifically by carboxylesterase, which exists preferentially in the liver in humans and monkeys. Particularly, derivatives having an N4-alkoxylcarbonyl moiety with a C4-C6 alkyl chain were the most susceptible to the human carboxylesterase. Those were then converted to 5'-deoxy-5-fluorouridine (5'-DFUR: 4) by cytidine deaminase highly expressed in the liver and solid tumors and finally to 5-FU by thymidine phosphorylase (dThdPase) preferentially located in tumors. When administered orally to monkeys, a derivative having the N4-alkoxylcarbonyl moiety with a C5 alkyl chain (capecitabine: 6) The highest AUC and Cmax for plasma 5'-DFUR. In tests with various human cancer xenograft models, capecitabine was more efficacious at wider dose ranges than either 5-FU or 5'-DFUR and was significantly less toxic to the intestinal tract than the others in monkeys.

MeSH terms

  • Administration, Oral
  • Animals
  • Antineoplastic Agents* / chemical synthesis*
  • Antineoplastic Agents* / chemistry
  • Antineoplastic Agents* / pharmacology*
  • Biological Availability
  • Capecitabine
  • Carbamates / chemical synthesis
  • Carbamates / pharmacokinetics
  • Carboxylic Ester Hydrolases / metabolism
  • Deoxycytidine / analogs & derivatives
  • Deoxycytidine / chemical synthesis*
  • Deoxycytidine / chemistry
  • Deoxycytidine / pharmacokinetics
  • Deoxycytidine / pharmacology*
  • Drug Delivery Systems / methods
  • Drug Delivery Systems / standards
  • Floxuridine / blood
  • Floxuridine / pharmacokinetics
  • Fluorouracil / blood
  • Fluorouracil / metabolism
  • Fluorouracil / pharmacokinetics
  • Humans
  • Intestines / enzymology
  • Kinetics
  • Liver / enzymology
  • Macaca fascicularis
  • Mice
  • Mice, Nude
  • Neoplasm Transplantation
  • Neoplasms, Experimental
  • Prodrugs / chemical synthesis
  • Prodrugs / pharmacokinetics
  • Prodrugs / standards
  • Structure-Activity Relationship
  • Substrate Specificity
  • Transplantation, Heterologous


  • Antineoplastic Agents
  • Carbamates
  • Prodrugs
  • Floxuridine
  • Deoxycytidine
  • Capecitabine
  • 5'-deoxy-5-fluorocytidine
  • Carboxylic Ester Hydrolases
  • Fluorouracil