Activity prediction models comparison

Lee, B.-C. and Danner, R.P., Prediction of infinite dilution activity coefficients in polymer solutions comparison of prediction models. Fluid Phase Equilibria, 128, 97, 1997. 

Comparison of the actual and predicted activity of compounds in the data set is used to guide refinement of the pharmacophore and active site models. A... 

To sum up, independent of the method applied, model building is a very delicate task and a lot of experience is required to reliably constmct stable and predictive models. This is some drawback in comparison to similarity searches whose application also requires experience but is conceptionally simpler. However, in cases where a sufficient number of active and inactive compounds are available, machine learning techniques are valuable tools for virtual screening (see Section 3.4.3.4). 

K = 22.7. Based on that single number, the activity coefficient model predicts the influence of concentration on via equation (4.22). It can be seen from Fig. 4.9 that the comparison of that prediction to the experimental data generally shows good agreement. Larger deviations are only observed for a few diluted samples and may partially be due to experimental errors. Results such as those shown in Fig. 4.9 are typical also for other esterifications. 

Predictive models for different solvent systems are currently also imder development. One direction is towards solvents used for natural gas processing. The first focus is on a mixture of MDEA activated with PZ. A comparison between predictions based on FTIR measurements and based on a combination of non-spectroscopic techniques will be made using in-line measurements at a laboratory pilot plant. 

The accuracy of the predicted thermodynamic data depends on the type of system and also on the thermodynamic properties. Group predictive models often predicted activity coefficients at infinite dilution with less accuracy. A comparison between a UNIFAC prediction and values measured by Atik et al. [38] shows relative deviations of 2.4, 8, 15, 17, and 29% for activity coefficients at infinite dilution [x = 10 ) of ethanol, acetone, benzene, 2-butanone, and 2-pentanone in water, respectively. 

In the case of complexes such as (21) and (23) which have an extended planar ligand, a significantly higher proportion of interstrand cross-links in DNA is formed in comparison to either cis- or trans-platin.172 The steric effects of these planar ligands result in the formation of structurally unique 1,2-interstrand cross-links like those formed by cisplatin, a unique example of how steric effects may alter a nonactive lesion into an active one (Figure 13).173,174 Model studies predicted this outcome by preparation of the monofunctional models trans-[PtCl(9-ethylguanine) (NH3)(quinoline)] and comparison of substitution rates of the Pt—Cl bond by G or C mononucleotides.175 176 Interestingly, the iminoether compound (25) appears to form predominantly monofunctional adducts with DNA.177... 

A comparison has been made between small scale test results and a field trial at a 17-ton scale for a solid compound [217]. The test results from a very sensitive calorimeter (Thermal Activity Monitor from ThermoMetric, Sweden) were substituted in a model, and the self-heating situation in bulk containers was predicted. The large-scale trial was carried out in a steel rectangular container lined with polyethylene. A control device was used to keep the container at a temperature of 40 to 45°C. Several thermocouples enabled monitoring of the temperature as a function of time in different places in the large container. 

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