The purpose of this study was to determine pharmacokinetic parameters of BR-28702-2, a new antineoplastic agent which is the conjugate of nucleotide and phospholipid, and to compare them with those of ara-C. Male rats were cannulated in the left femoral vein and received a single i.v. bolus dose of either BR-28702-2 or ara-C. BR-28702-2 was also administered i.p. and plasma samples were analyzed by reversedphase HPLC. The t$_{1}$2($eta$)/ of ara-C(1.22 hr.) was significantly smaller than that of BR-28702-2(4.420 hr.). The absolute bioavailability of BR-28702-2 after i.p. injection was 1.125%. This lower bioavailability, together with previous reports that marked antineoplastic activity was observed when given i.p., indicates that BR-28702-2 would act as a depot system to release active moieties. Further works, therefore, need to be done to characterize active metabolites.