A monophosphate form of gemcitabine; in nanoparticle form it has synergistic effects when used in combination with cisplatin nanoparticles in vitro at a one-to-one molar ratio (IC50s = 5.95, 34.8, and 15.7 μM for nanoparticle combination, gemcitabine monophosphate alone, and cisplatin alone, respectively); in nanoparticle form it inhibits tumor growth and increases apoptosis in a stroma-rich mouse xenograft model