Benzoylphenylurea
Benzoylphenylurea is a low molecular weight agent with antineoplastic activity. Benzoylphenylurea binds to the colchicine binding site on tubulin, thereby blocking tubulin polymerization and disrupting mitotic function.  This agent also inhibits DNA polymerase, and has been shown to arrest leukemia cells in the G1-S transition phase of the cell cycle. (NCI04)