A potent tubulin polymerization inhibitor that reduces tumor growth in P-388 (leukemia), SK-N-SH (neuroblast), BXPC-3 (pancreas), NCI-H460 (lung), and DU-145 (prostate) cell lines with ED50 values of 0.0029, 0.00025, 0.23, 0.00035, and 0.00072 μg/ml, respectively; disrupts tumor blood flow in a rat model of carcinosarcoma at a dose of 100 mg/kg without affecting normal tissues