“…A further research in this field in search of safer and more potent compounds led to the discovery of milrinone and its analogs (Bekhit and Baraka, 2005;Abadi et al, 1999). To develop SAR in the series, several pyridazinone derivatives of amrinone were also synthesized (Combs et al, 1992;Bakewell et al, 1990;McCall et al, 1986;Pastelin et al, 1983). Their mechanism of action was established, and a five-point model and pharmacophore were identified (Leclerc et al, 1986;Erhardt et al, 1988;Bristol et al, 1984).…”