Novel camptothecin derivatives. Part 1: oxyalkanoic acid esters of camptothecin and their in vitro and in vivo antitumor activity.

A series of oxyalkanoic acid esters of (20S)-camptothecin derivatives was prepared by the method of acylation. Their antitumor activity was evaluated on cancer cells in vitro by the colony formation assay and in vivo. These newly synthesized derivatives show a dramatically higher chemotherapeutic activity in killing human cancer cells than the parent drug, camptothecin, and clinically available drugs, irinotecan and taxol.