In the last few years, the pyridazine derivatives have been found to exhibit a wide range of pharmacological activities. A large number of research articles and patents described them, and several drugs based on its nucleus have come into light. Pyridazinone, a derivative of pyridazine, was initially exploited in search of cardiovascular drugs and for its use in agrochemicals, but later on this nucleus was found to be associated with plethora of activities. In this article, we have reviewed the influence of structural changes on the pharmacodynamic profile of the pyridazinone moiety.

Imidazoles being good Pharmacophore for anticancer series were exploited for their potential in the present study. Some new 2,5,6-trisubstituted imidazo (2,1-b)-1,3,4-thiadiazole possesing antineoplastic potential against 3 cell lines i.e. murine leukemia cells (L1210/0) and human T-lymphocyte cells (Molt4/C8 and CEM/0) were selected for studies. The IC 50 values were taken along with the structures and a quantitative structure activity relationship was established for these novel 2,5,6-trisubstituted imidazo(2,1-b)-1,3,4-thiadiazole derivatives. The descriptors were calculated with the help of Chem 3D and Dragon software. Codessa and Vlife software were used to generate QSAR models. MLRA, PCR AND PLSR are the statistical tools employed for the study. The models developed had shown good statistical correlation with R 2 =0.99 and Q 2 =0.98. The QSAR models generated were also validated by using test compounds which have shown comparable results to the experimental values.

The recent interests in the development of novel and potent bifunctional quinolonyl diketo acid derivatives as integrase inhibitors for the treatment of HIV-1 infection-inhibiting 3 0 processing and strand transfer in the virus have been explored using classical Quantitative Structure Activity Relationship (QSAR) tools in an attempt to delve into the quantitative contribution pattern of different substituent in the diketo quinoline ring to the activities. Various physico-chemical parameters have been used along with the appropriate indicator and/or integer variables to develop QSAR equations. The models developed were of acceptable statistical quality and predictive potential. The results show that for response variables, presence of 3D-Morse, WHIM, Topological and RDF descriptors contributes significantly towards the 3 0 -processing and strand transfer process inhibitory activities.