To model the biotransformation steps of 5-FU production from capecitabine and identify patient characteristics that may influence the drug disposition.Blood samples and demographic data were collected from two phase I studies in which adult patients received oral capecitabine for various malignancies. Capecitabine, 5'-deoxy-5-fluorocytidine (5'-DFCR), 5'-deoxy-5-fluorouridine (5'-DFUR) and 5-fluorouracile (5-FU) concentration-time data were analysed via a population approach using NONMEM.Forty patients and 75 pharmacokinetic time-courses were available for analysis. Capecitabine pharmacokinetics was ascribed to a one compartment model from which 5'-DFCR, 5'-DFUR and 5-FU were sequentially produced. Capecitabine oral absorption was characterized by a rapid first order input (K(a)=2.1 +/- 0.3 hr(-1)) with a lag time (0.28 +/- 0.11 hr), but related inter-occasion (IOV) and inter-subject (ISV) variabilities for these parameters, 167

作者：Saik, Urien；Keyvan, Rezaí；Fran?ois, Lokiec

来源：Journal of pharmacokinetics and pharmacodynamics 2005 年 32卷 5-6期