# What does the symbol represent in QSAR equation?

## What does the symbol represent in QSAR equation?

29) What symbol is used to represent molar refractivity as a steric factor in a QSAR equation? Feedback: MR is the symbol used to represent molar refractivity as a steric factor. R is used to represent an aromatic substituent’s electronic resonance effect.

**How do you know if a QSAR equation is valid?**

In general, a QSAR model is acceptable when it has an r2 value greater than 0.6 and r2 (CV) greater than 0.5 [15,16]. The r2 (CV) value of 0.71 exhibits a good internal predictive power of the developed model. The model also showed an r2 value of 0.87.

### What does R represent in QSAR?

The QSAR equation relating the insecticidal activity of a series of diethyl phenylphosphonates versus σ is shown below. What does r represent? a) The regression or correlation coefficient.

**Why is log P important in drug formulation?**

LogP is directly related to the drug lipophilicity which is a key property for the solubility, absorption, membrane penetration, plasma protein binding, distribution, and tissue penetration. Due to the importance of the drug lipophilicity, logP is a component of the Lipinski rule of five.

## How is QSAR applied in drug discovery?

QSAR-Based Virtual Screening: Advances and Applications in Drug Discovery. Virtual screening (VS) has emerged in drug discovery as a powerful computational approach to screen large libraries of small molecules for new hits with desired properties that can then be tested experimentally.

**What is cross validation in QSAR?**

CV is often. used to determine how large a model can be used for a. given data set. A cross-validated R is usually smaller than. the overall R for a QSAR equation.

### What is Hansch equation in QSAR?

Hansch equation: log 1/C = 1.151 π -1.464 σ+ +7.817 ( n = 22; r = 0.945; s = 0.196; F = 78.6; Q2 =0.841; Spress = 0.238) N: nr. of compounds R: internal validation correlation coefficient S: standard deviation; measure of absolute quality of model (should be < 0.3) Q2: cross validated R2.

**What is Q squared in QSAR?**

R2 is the squared correlation coefficient of the model assessed by the training set values. Q2(F1), Q2(F2), and Q2(F3) are the model predictive ability from an external evaluation set on the basis of three different functions. rmse is the root-mean-square error over the external test set.

## What is partition coefficient in QSAR?

The partition coefficient (log P) is a physicochemical parameter defined as the ratio (as logarithm) between the equilibrium concentrations of a substance dissolved in a two-phase system consisting of a polar and less polar for the most part immiscible solvent.