In vitro time course assays for four renal selective compounds. In vitro time course assays for four renal selective compounds. Renal line A498 was exposed to a wide range of concentrations for various times. Profiles of activity demonstrate that all agents confer near maximum activity with brief drug exposures (≤3 h) to similar drug concentrations (with the possible exception of NSC 281613, which appears to require somewhat higher molar drug concentrations at the shorter intervals). Susan D. Mertins et al. Clin Cancer Res 2001;7:620-633 ©2001 by American Association for Cancer Research