WATER-SOLUBLE INHIBITORS OF TOPOISOMERASE-I - QUATERNARY SALT DERIVATIVES OF CAMPTOTHECIN

Eleven water soluble 7-substituted quaternary ammonium salt derivative s of 10,11-(methylenedioxy)- and 10,11-(ethylenedioxy)-(20S)-camptothe cin were synthesized via the Friedlander reaction followed by nucleoph ilic displacement with an aromatic amine. All of these compounds were more potent than camptothecin in the in vitro cleavable complex assay. These inherently charged camptothecin derivatives were cytotoxic agai nst three different human tumor cell lines (SKOV3, an ovarian adenocar cinoma; SKVLB a multidrug resistant ovarian adenocarcinoma; and HT-29, a colon carcinoma). A selected group of five compounds was evaluated in the nude mouse HT-29 xenograft model. Two of these quaternary salts (17 and 18) were more efficacious than Topotecan in delaying tumor gr owth. In an extended in vivo model, 18 demonstrated tumor regression.