DW2282, (S)- (+)-4-phenyl -1-[N-(4-am mob enzoyl) -indolin-5- sulfonyl]-4,5- dihydro-2-imidazolone hydrochloride, is a novel anticancer agent thought to have an unique mechanism of action on the inhibition of tumor growth. In this study, we estimated in vivo antitumor activities and pharmacokinetics of Dw2282 depending on various vehicles. The inhibition rate of tumor growth was increased by 50, 100 and 200 mg/kg of Dw2282 in a dose-dependent manner. When Dw2282 dissolved in 4 sorts of vehicles was orally single dosed to rats at 50 mg/kg, Cmax of Dw2282 in 0.5% CMC.Na was a half as high as those in PG, PG+CP and PG+CP+DW. When Dw2282 was orally administered to mice for 5 days, antitumor activity of 130 mg/kg suspended in 0.5% CMC.Na was as effective as that of 65 mg/kg dissolved in the rest of vehicles. Taken together, it is thought that antitumor activities of Dw2282 are resulted from the absorption extent of it and related to the vehicle used.