Synthesis and Antitumor Activity of A-Ring or E-Lactone Modified Water Soluble Prodrugs of 20(S)-Camptothecin, Including Development of Irinotecan Hydrochloride Trihydrate (CPT-11)

Abstract

Camptothecin was converted into derivatives which have substituents on the A- and B­ rings . One potent and less toxic derivative , 7-ethyl-10-hydroxycamp-tothecin (SN-38), was selected and then converted into glycosides, sulfates, phosphates and carbamates at the 10-hydroxyl group. Among these water-soluble, E-lactone-intact derivatives , the hydrochloride trihydrate of 7-ethyl-10 - [(4-piperidinopiperidine )carbony loxy]camptothecin(irinotecan hydrochloride trihydrate , CPT-11) had a broad spectrum of antitumor activity and seems to be a promising anticancer agent with a new mode of action. The E-lactone ring was modified for derivatization of camptothecin s which have no foothold on the A- or B­ring. The 17-0-acyl derivatives of the N,N-dimethylethylenediamine amide of camptothecin were stable in aqueous solution. Good activity was dependent on enzymatic hydroly sis of the 17-0-acyl group of the amide to yield the 17-hydroxyl amide, which was readily hydrolyzed under physiological conditions , thereby yielding the active lactone compound .