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In The Name OF God. Design of experiments applied to QSAR. Chemometrices: Signal processing Classification & pattern reccognation Experimental design Multivariative calibration Quantitative Structure - Activity Relationship(QSAR).
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In The Name OF God Design of experiments applied to QSAR
Chemometrices: • Signal processing • Classification & pattern reccognation • Experimental design • Multivariative calibration • Quantitative Structure - Activity Relationship(QSAR)
Quantitative Structure-ActivityRelationship (QSAR) Models Set of molecules Y parameter Molecular Descriptors (Xi) QSAR Y = f(Xi) Interpretation Prediction
Step1: Formulation of Classes of Similar Compounds Step 2: Structural Description and Definition of Design Variables Step 3 :Selection of the Training Set of Compounds Step 4:Biological Testing Step 5 :QSAR Development Step6 :Validation and Predictions for Non-Tested Compounds
Selection of the Training Set of Compounds • well-balanced distribution & contain representative compound • systematically & simultaneously
set of neuropeptides Relative activity against NK1 receptors • 29 full FD 512 structures • 29-4fractional design 32 structures 512-32 = 480 9 of 11 positions
QSAR:Same molecular set • Samemolecular set • full molecular library Formal Inference-based Recursive Modeling (FIRM) methodology • Samekey points • not preserve exactly the same ordering or magnitude of Importance Second order interactions
Y = 25.094 + 8.031 [Leu] + 8.094 [Phe-2] + 5.781 [Leu] [Phe-2] + 11.593 [Phe-1] + 9.094 [Gln-2] + 7.844 [Phe-1] [Gln-2] + 5.031 [Gln-2] [Gln-1] + 7.031 [Pro-2] [Phe-1] • Interaction effect important • Experimental Response Variability = 5% • Variation ►Least a change of 5% in the molecular activity
Dipeptides (Inhibiting the Angiotensin Converting Enzyme) • Predictive capability of a QSAR model • Strategy used for selecting the compounds in the training set
FFD • Table 1. The 2 4-1FFDfor z1, and z2for a peptide varied at twopositions (I and 2). The design is cornpleinentcd with a centcr point. Dipeptidcs (DP) corresponding approxiniatcly to the settings of the angiotcnsin data are givcn.
FD Table 2. The 24FD for z1 , and z2 at position 1 and 2. Peptide analogs, approximatcly corresponding to thc design matrix, were selected from the set of 48 bitter dipcptidcs.
Full Factorial Design(FD) • Fractional Factorial Design (FFD) • change-one-separate-feature-at-a-time (COST) design