title: In vitro cytostatic activity of 1,2,4-triazolo- and 1,2,3,4-tetrazolo pyridazines.
abstract: Out of a series of fourteen 1,2,4-triazolo(4,3-b)-, and 1,2,3,4-tetrazolo-(1,5-b)pyridazine derivatives, 4 compounds have been found to reveal high cytostatic activity in KB and HeLa human cancer cell lines in vitro with ED50 activity values ranging from 0.25 to 3.0 micrograms/cm3 (0.009-0.158 x 10(-4) mole/l), and according to DR and D, NCI, NIH Bethesda criterion were qualified for further in vivo screening investigation. 6-Chloro-8-(N,N-dimethylaminosulfonylmethyl)-1,2,3,4-tetrazolo+ ++-(1,5-b)- pyridazine exhibited the strongest in vitro cytostatic activity (ED50 = 0.009 x 10(-4) mole/l), comparable with the best standards, and higher in comparison with a standard cytosine arabinoside (ED50 = 0.03-0.04 x 10(-4) mole/l). The presence of chlorine atom at C-6 position in the pyridazine ring determines the cytotoxic activity of tetrazolopyridazines as the primary factor and C-8 substituents, which influence their better solubility seems to be a secondary one, as confirmed by the results of the structure-activity and solubility-activity relationship analysis. However, for the exhibition of the triazolopyridazine activities the presence of two chlorine atoms at C-6 and C-3 position was essential.
authors.affiliation: Department of Pharmacology, Karol Marcinkowski University of Medical Sciences, Poznań, Poland.
authors.forename: B
authors.initials: B
authors.lastname: Hładoń
authors.forename: H
authors.initials: H
authors.lastname: Laskowska
authors.forename: A
authors.initials: A
authors.lastname: Sloderbach
authors.forename: E
authors.initials: E
authors.lastname: Melzer
mesh_terms: D000970:Antineoplastic Agents / Q000138:chemical synthesis / Q000737:chemistry / Q000494:pharmacology*; D004354:Drug Screening Assays, Antitumor; D006367:HeLa Cells; D006801:Humans; D007624:KB Cells; D011724:Pyridazines / Q000138:chemical synthesis / Q000737:chemistry / Q000494:pharmacology*; D013329:Structure-Activity Relationship; D013777:Tetrazoles / Q000138:chemical synthesis / Q000737:chemistry / Q000494:pharmacology*; D014230:Triazoles / Q000138:chemical synthesis / Q000737:chemistry / Q000494:pharmacology*
chemical_list: C112137:6-chloro-8-(N,N-dimethylaminosulfonylmethyl)-1,2,3,4-tetrazolo-(1,5-b)pyridazine; D000970:Antineoplastic Agents; D011724:Pyridazines; D013777:Tetrazoles; D014230:Triazoles