Pyridazin-3(2H)-one derivatives have attracted the attention of medicinal chemists during the last decade due to their diverse pharmacological activities. Easy functionalization of various ring positions of pyridazinones makes them an attractive synthetic building block for designing and synthesis of new drugs. The incorporation of this versatile biologically accepted pharmacophore in established medicinally active molecules results in wide range of pharmacological effects. Pyridazinones constitute an interesting group of compounds, many of which possess wide spread pharmacological properties such as antihypertensive, platelet aggregation inhibitory, cardiotonic activities and some are also well known for their pronounced analgesic, anti-inflammatory, antinociceptive, and antiulcer activities. Recently pyridazinones have also been reported as antidiabetic, anticonvulsant, antiasthmatic, and antimicrobial agents. These encouraging reports suggest that this privileged skeleton should be extensively studied for the therapeutic benefits. In view of this, a detailed and updated account of the pharmacological properties of pyridazinones is described in this review. The wide range of synthesized pyridazinone analogs along with their medicinal significance is also presented.
