3.1.1
Capecitabine (Xeloda) is a fluoropyrimidine carbamate precursor of 5-FU. It is given orally and is converted via several enzymatic steps to give intratumoural release of 5-FU. The enzyme involved in the final conversion to 5-FU, thymidine phosphorylase, is found at higher levels in tumour tissues than in normal tissue, thereby reducing systemic exposure to 5-FU.