[Pharmacological characterization of novel pyridazines. Part 2: Analgetic, antipyretic and antiphlogistic activity...

Using the tail-flick and the hot-plate method as well as the Writhing syndrome as screening procedures, the author tested newly synthetized pyridazine derivatives for analgetic activity in the mouse. Of the 17 compounds tested, the sulphur-containing derivative 3-amino-4-mercapto-6-methylpyridazine (17) has been found to be the most active one. The relatively great effectiveness of 17 was also confirmed in rats (antipyresis model and acute oedema of the hind paw), this substance being superior to all the other compounds under investigation with regard to the quality of the antipyretic and antiphlogistic effects. Further studies of the analgetic, antipyretic and antiphlogistic activity of this group of substances are planned. In this connection, the synthesis of other sulphur-containing pyridazine derivatives seems especially desirable.