Quantitative structure-activity problems with

Quantitative Structure—Activity Relationships. Many quantitative stmcture—activity relationship (QSAR) studies of progestins have appeared in the Hterature and an extensive review of this work is available (174). QSAR studies attempt to correlate electronic, steric, and/or hydrophobic properties to progestational activity or receptor binding affinity. A review focusing on the problems associated with QSAR of steroids has been pubUshed (175). 

Over the last 40 years, the scientific literature has abounded with examples of the application of quantitative structure-activity relationships (QSARs) and molecular modeling techniques to the problem of predicting biological activity. The application of these techniques to the prediction of pharmacokinetic or toxicokinetic parameters has been, until recently, less intensely researched. 

While the classical models of quantitative structure-activity analyses do not consider the three-dimensional arrangement of functional groups, some recent approaches deal with this problem and describe biological activities in terms of favorable and unfavorable interaction spheres, derived from the hydrophobic, electrostatic, and steric interaction fields of the ligands. 

Chemometrics Multivariate View on Chemical Problems Combined Quantum Mechanics and Molecular Mechanics Approaches to Chemical and Biochemical Reactivity Environmental Chemistry QSAR Infrared Data Correlations with Chemical Structure Quantitative Structure-Activity Relationships in Drug Design Quantitative Structure-Property Relationships (QSPR). 

Artificial Intelligence in Chemistry Chemical Engineering Expert Systems Chemometrics Multivariate View on Chemical Problems Electrostatic Potentials Chemical Applications Environmental Chemistry QSAR Experimental Data Evaluation and Quality Control Fuzzy Methods in Chemistry Infrared Data Correlations with Chemical Structure Infrared Spectra Interpretation by the Characteristic Frequency Approach Machine Learning Techniques in Chemistry NMR Data Correlation with Chemical Structure Protein Modeling Protein Structure Prediction in ID, 2D, and 3D Quality Control, Data Analysis Quantitative Structure-Activity Relationships in Drug Design Quantitative Structure-Property Relationships (QSPR) Shape Analysis Spectroscopic Databases Structure Determination by Computer-based Spectrum Interpretation. 

With the development of accurate computational methods for generating 3D conformations of chemical structures, QSAR approaches that employ 3D descriptors have been developed to address the problems of 2D QSAR techniques, that is, their inability to distinguish stereoisomers. Examples of 3D QSAR include molecular shape analysis (MSA) [26], distance geometry,and Voronoi techniques [27]. The MSA method utilizes shape descriptors and MLR analysis, whereas the other two approaches apply atomic refractivity as structural descriptor and the solution of mathematical inequalities to obtain the quantitative relationships. These methods have been applied to study structure-activity relationships of many data sets by Hopfinger and Crippen, respectively. Perhaps the most popular example of the 3D QSAR is the com-... 

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