Structure activity relationship of drugs pdf

QSAR models relate the predictor variables to a categorical value of the response variable. Different properties or behaviors structure activity relationship of drugs pdf chemical molecules have been investigated in the field of QSPR.

As an example, biological activity can be expressed quantitatively as the concentration of a substance required to give a certain biological response. Additionally, when physicochemical properties or structures are expressed by numbers, one can find a mathematical relationship, or quantitative structure-activity relationship, between the two. Fragmentary values have been determined statistically, based on empirical data for known logP values. Group or Fragment based QSAR is also known as GQSAR. GQSAR allows flexibility to study various molecular fragments of interest in relation to the variation in biological response. The molecular fragments could be substituents at various substitution sites in congeneric set of molecules or could be on the basis of pre-defined chemical rules in case of non-congeneric sets.

GQSAR also considers cross-terms fragment descriptors, which could be helpful in identification of key fragment interactions in determining variation of activity. Lead discovery using Fragnomics is an emerging paradigm. In this context FB-QSAR proves to be a promising strategy for fragment library design and in fragment-to-lead identification endeavours. An advanced approach on fragment or group-based QSAR based on the concept of pharmacophore-similarity is developed. It uses computed potentials, e. The four applications allow to build a 3-D QSAR model from scratch by simply knowing the training set structures and bioactivities. 3-D QSAR maps in a 3-D fashion and interactive way.