Recent Advances in QSAR Studies

This book presents an interdisciplinary overview on the most recent advances in QSAR studies. The first part consists of a comprehensive review of QSAR methodology. The second part highlights the interdisciplinary aspects and new areas of QSAR modelling.

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Since the inception of this volume, the world's nancial climate has radically changed. Theemphasishasshiftedfromboomingeconomiesandeconomicgrowth totherealityofrecessionanddiminishingoutlook. Witheconomicdownturncomes opportunity,inallareasofchemistryfromresearchanddevelopmentthroughto productregistrationandriskassessment,replacementsarebeingsoughtforcostly time-consumingprocesses. Leadingamongstthereplacementsaremodelswithtrue predictivecapability. Ofthesecomputationalmodelsarepreferred. This volume addresses a broad need within various areas of the "chemical industries", from pharmaceuticals and pesticides to personal products to provide computationalmethodstopredicttheeffects,activitiesandpropertiesofmolecules. Itaddressestheuseofmodelstodesignnewmoleculesandassesstheirfateand effectsbothtotheenvironmentandtohumanhealth. Thereisanemphasisrunning throughoutthisvolumetoproducerobustmodelssuitableforpurpose. Thevolume aimstoallowthereaderto nddataanddescriptorsanddevelop,discoverandutilise validmodels. Gdansk, ' Poland TomaszPuzyn Jackson,MS,USA JerzyLeszczynski Liverpool,UK MarkT. D.
Cronin May2009 CONTENTS Part I Theory of QSAR 1 QuantitativeStructure-ActivityRelationships(QSARs)- ApplicationsandMethodology...3 Mark T. D. Cronin 1. 1. Introduction...3 1. 2. PurposeofQSAR...4 1. 3. ApplicationsofQSAR...4 1. 4. Methods...5 1. 5. TheCornerstonesofSuccessfulPredictiveModels ...7 1. 6. AValidated(Q)SARoraValidPrediction? ...9 1. 7. UsinginSilicoTechniques ...9 1. 8. NewAreasforinSilicoModels...11 1. 9. Conclusions...11 References ...11 2 TheUseofQuantumMechanicsDerivedDescriptorsin ComputationalToxicology...13 Steven J. Enoch 2. 1. Introduction...13 2. 2. TheSchrodingerEquation...15 2. 3. Hartree-FockTheory...17 2. 4. Semi-EmpiricalMethods:AM1andRM1...18 2. 5. ABInitio:DensityFunctionalTheory...19 2. 6. QSARforNon-ReactiveMechanismsofAcute(Aquatic) Toxicity...19 2. 7. QSARsforReactiveToxicityMechanisms...21 2. 7. 1. AquaticToxicityandSkinSensitisation...21 2. 7. 2. QSARsforMutagenicity ...24 2. 8. FutureDirectionsandOutlook...25 2. 9. Conclusions...26 References ...26 vii viii Contents 3 MolecularDescriptors...29 Viviana Consonni and Roberto Todeschini 3. 1. Introduction...29 3. 1. 1. De nitions...29 3. 1. 2. History...31 3. 1. 3. Theoreticalvs.
ExperimentalDescriptors...33 3. 2. MolecularRepresentation ...35 3. 3. TopologicalIndexes...38 3. 3. 1. MolecularGraphs...38 3. 3. 2. De nitionandCalculationofTopologicalIndexes(TIs) 39 3. 3. 3. Graph-TheoreticalMatrixes...42 3. 3. 4. ConnectivityIndexes ...48 3. 3. 5. CharacteristicPolynomial ...50 3. 3. 6. SpectralIndexes ...53 3. 4. AutocorrelationDescriptors ...