“…There are many cardioactive pyridazinone derivatives, which are either in clinical use or have been tested in clinical trials, for example, imazodan 7,8 , CI-930 8,9 , pimobendan 8,10 , indolidan 8,11 , levosimendan 8,12 , SK&F-93741 8,13 , Y-590 8,14 , Meribendan 15 , NSP-804 16 , NSP-805 16 , bemoradan 17,18 , senazodan 19 , amipizone 8,18 , prinoxodan 20 , SKF 95654 21 , siguazodan 22 and KF 15232 22 . Some of these pyridazinone derivatives were found not suitable for further development because of their side effects and low potency.…”