 1: 13011317 (2009) Bhandari   1301 Pharmacological Screening of ovel itric Oxide Donars Containing 1, 5Diaryl Pyrazolin3One as on Toxic SAIDs Shashikant V. Bhandari, Sudarshan C. Dangre, Kailash G. Bothara, Aniket P. Sarkate, Ajit A. Patil. Department of Pharmaceutical Chemistry, A.I.S.S.M.S College of Pharmacy, ear RTO, Kennedy Road, Pune411001, Maharashtra, India. Summary Various substituted 1,5!diarylpyrazol!3!one derivatives were screened for analgesic, anti! inflammatory activities, ulcerogenic potential and for their ability to release Nitric oxide. Most compounds exhibited significant analgesic and anti!inflammatory activities. It was interesting to note that out of ten compounds, 7j (59.64%) was found to have anti! inflammatory activity greater than the standard drug Indomethacin (57.89%), whereas compound 7b (57.89%) was found to be equipotent to that of standard, Indomethacin. The compounds also showed significantly reduced GI!ulcerogenicity and gastroprotective results in histopathological studies i.e. they were found to be causing no mucosal injury. All the synthesized compounds were found to exhibit significant nitric oxide releasing activity, in both in!vitro and in!vivo models. Thus, the rationale used to design the NCEs was found to produce the promising results as anticipated. Key words: 1,5!diarylpyrazolin!3!one; Nitric oxide; Anti!inflammatory; Analgesic; Non! ulcerogenic; Vasodilatory. Corresponding author: Prof. Shashikant V. Bhandari Department of Pharmaceutical Chemistry, A.I.S.S.M.S College of Pharmacy, Near RTO, Kennedy Road, Pune!411001, Maharashtra, India. Email: drugdesign1@gmail.com drugdesign1@rediffmail.com Phone: ! +91 20 26058204; Telefax:! +91 20 26058208.