Figure 5.
Intracellular SN-38 concentration measurement in HMVEC-d cells after the exposure to axitinib, SN-38, and their simultaneous combination for 72 hours. Representative high-performance liquid chromatography chromatograms of a spiked standard of SN-38 (A), drug-free vehicle-treated sample (blank, B), axitinib-treated sample (C), SN-38-treated sample (D), and axitinib + SN-38 combination sample (E). Interfering peaks were not noted at the retention time of SN-38 (arrow) in the drug-free sample. Quantification of the SN-38 concentrations in 105 HMVEC-d cells (F). Columns and bars indicate mean values ± SE, respectively. *P < .05 versus SN-38-treated samples.