<正> Objective: To investigate the association of the transportation characteristics of nolatrexed in tumor cells with its drug sensitivity. Methods: The sensitivity of 3 tumor cell lines

C6

SRS82 and LoVo

to nolatrexed were determined by growth inhibition study. After exposure to 20 μmol/L nolatrexed at different time intervals ranging from 0 to 30 min

or to nolatrexed at different concentrations ranging from 0 to 40 μmol/L for 10 min

the intracellular drug concentration was measured using high-performance liquid chro-matography. Results: C6 was the most sensitive cell line among the three

with sensitivity 6. 8-fold and 13. 8-fold those of SRS-82 and LoVo cells respectively. Transportation of nolatrexed in the 3 cell lines were qualitatively similar

which rapidly achieved steady-state within 5 min

and linear relationship between the intracellular and extracellular drug concentration was observed. The intracellular steady-state level achieved in C6 was significantly higher than those in the other t