Synthesis and cytotoxic activity of platinum complex immobilized by branched polyethylene glycol

Two-arm branched mPEG (monomethoxy-polyethylene glycol) with different molecular weights (Mn = 4000, 6000, 9400) was synthesized and used as carrier for immobilization of cisplatin [cis-diammine(dichloro)platinum (II), CDDP]. As a contrast, CDDP modified with linear mPEGs was also synthesized. All these polymeric drugs modified with branched mPEG are water soluble and show higher cytotoxic activity against C6 human breast cancer cells than cisplatin modified with linear mPEG with the same molecular weight. All the polymeric CDDP showed a much lower toxicity than the CDDP.