Lipophilicity calculation

Raevsky, O. A. Molecular lipophilicity calculations of chemically heterogeneous... 

Note that the distribution coefficient depends only on pH, pKa values, and P (not on concentration of sample species). Equation (4.7) is applicable to all lipophilicity calculations. Special cases, such as eq. 4.9, have been tabulated [275],... 

Some lipophilicities calculated from the parameters of Hansch (Table 5) are listed in Table 12. These values are only of qualitative significance, since it is not known how well the n parameters apply to these substances, but they illustrate the lipophilicity changes brought about by some structural changes. A direct determination of quantitative partition coefficients should be a simple matter. 

Rabbe, C., Sella, C., Madic, C., Godard, A. 1999. Molecular modeling study of uranyl nitrate extraction with monoamides. II. Molecular mechanics and lipophilicity calculations. Structure-activity relationships. Solvent Extr. Ion Exch. 17 (1) 87-112. 

The measurement of lipophilicity value for all three families of 5-thio-carbopeptides is essential for their potential affinity effect to cell membrane and the level of penetration/diffusion through membrane. The detailed values of measured lipophilicity calculated as log P via molecular modeling will be published separately as collaborative work effort. These particular data are essential for preliminary biological screening for all thioglycomimetics for selective in vitro cell viability assays as reported by us earlier (27)... 

Fiirst Sandor utca 5 H-1136 Budapest, Hungary Tel. 36-1-112-4874, fax 36-1-132-2574 Prediction of metabolic products based on a library of known transformations. HARZARDEXPERT for prediction of toxicity. MOLIDEA for molecular modeling, molecular mechanics CNDO/2 and CNDO/S calculations. DRUGIDEA for QSAR. LABSWARE for general computations and statistics. PRO-LOGP for lipophilicity calculation using R. F. Rekker method. PC. 

Measurement of log P and log D can be automated, but there are many in silico methods available. Every fragment of an organic compound has a defined lipophilicity. Calculation of log P can be made computationally by summing the fragments to give a total lipophilicity (Leo etal., 1971 Rekker andMannhold, 1992) A variety of methods... 

Moreover, and as expected from the foregoing discussion on recognition forces, the precision of lipophilicity calculations is expected to be greatly improved if intramolecular interaaions are taken into account. However, a full... 

The lipophilicity (7 m value) and specific hydrophobic surface area of pyrido[l,2-a]pyrazinium-l-olates 342 and -3-olate 343, and l-(4-chlorophe-nyl)-l-hydroxy-l,2-dihydropyrazino[2,l-a]isoquinolinium salt (344) has been measured by reversed-phase thin-layer chromatography (98MI13). Partition coefficient (log/ ) of 9-bromo-5-[(A-phenylaminocarbonyl)-methyl]-l,2,3,5,6,7-hexahydropyrido[l,2,3- fc]quinoxaline-2,3-dione was calculated to be 2.78 (97JMC4053). 

One of the most important characteristics of the emulsifier is its CMC, which is defined as the critical concentration value below which no micelle formation occurs. The critical micelle concentration of an emulsifier is determined by the structure and the number of hydrophilic and hydrophobic groups included in the emulsifier molecule. The hydrophile-lipophile balance (HLB) number is a good criterion for the selection of proper emulsifier. The HLB scale was developed by W. C. Griffin [46,47]. Based on his approach, the HLB number of an emulsifier can be calculated by dividing... 

The conditional association constant for [18]aneN4 ( cyclic spermine ) with ATP - at pH 7.5 is calculated from the (3L value (Table 5) and protonation constants (Table 1) to be 2.4x 105 M-1, which is larger than the association constants for the linear spermidine (9 xi 02 M ) and spermine (9.5 x 103 M-1)23). It is also of interest that cyclic spermine is selective for ATP over AMP (ratio association constants is 700), while linear spermine prefers ATP to AMP only by a ratio of 26 to 1 43). The selective complexation of biologically important anions is of particular interest, especially if the ligands are converted into selective anion carriers by attachment of lipophilic hydrocarbon chains. 

Fig. 1.7 Correlation between virtual log P (calculated with the molecular lipophilicity potential) and the dipole moment (f = 0.76) as obtained from MD simulation of acetylcholine in water. Reproduced from Ref [16] with kind permission of American Chemical Society 2005.

Mannhold, R., Dross, K. Calculation procedures for molecular lipophilicity a comparative study. Quant. Struct.-Act. Relat. 1996, 15, 403 09. 

Mannhold, R., Crudani, G., Dross, K., Rekker, R. F. Multivariate analysis of experimental and calculative descriptors for molecular lipophilicity. J. Comput.-Aided Mol. Design 1998, 12, 573-581. 

Rekker, R. F., Mannhold, R. Calculation of Drug Lipophilicity. The Hydrophobic Fragmental Constant Approach, VCH, Weinheim, 1992. 

The importance of molecular size and H-bond strength for octanol-water partitioning is used by the SLIPPER model [13, 14], which calculates lipophilicity for... 

Of course, the shape of the lipophilicity profiles becomes much more complicated for molecules with multiple ionized forms. Nevertheless, the partition coefficients may be calculated from the distribution coefficient using the general equation [113] ... 

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