KEL and neoplasm: For example, we limited kepr/kel to achieve tumor accumulations that are consistent with those reported in vivo in a mouse model, ranging from 0.01–10% and 0.001–1% ID for Doxil and doxorubicin respectively [15, 22, 23]; free doxorubicin reaches maximum accumulation faster in tumors but remains at concentrations roughly 10 times less than liposomal formulations due to differences in pharmacokinetics and uptake mechanisms [12, 23, 24].