Partition coefficients correlation coefficient

An overview of some basic mathematical techniques for data correlation is to be found herein together with background on several types of physical property correlating techniques and a road map for the use of selected methods. Methods are presented for the correlation of observed experimental data to physical properties such as critical properties, normal boiling point, molar volume, vapor pressure, heats of vaporization and fusion, heat capacity, surface tension, viscosity, thermal conductivity, acentric factor, flammability limits, enthalpy of formation, Gibbs energy, entropy, activity coefficients, Henry s constant, octanol—water partition coefficients, diffusion coefficients, virial coefficients, chemical reactivity, and toxicological parameters. 

Isnard, P., Lambert, S. (1989) Aqueous solubility/w-octanol-water partition coefficient correlations. Chemosphere 18, 1837-1853. 

Isnard, P., and S. Lambert, Aqueous Solubility and n-Octanol/Water Partition Coefficient Correlations. Chemosphere, 1989 18, 1837-1853. 

Isnard, P, Lambert, S. (1989) Aqueous solubility/n-octanol water partition coefficient correlations. Chemosphere 18, 1837-1853. Iwasa, J., Fujita, T., Hansch, C. (1965) Substituent constants for aliphatic functions obtained from partition coefficients.. /. Med. Chem. 8, 150-153. 

Harris, M.J., Higuchi, T., and Rytting, J.H. Thermodynamic group contributions from ion-pair extraction equilibriums for use in the prediction of partition coefficients correlation of surface area with group contributions. 7. Phys. Chem. 1973, 77, 2694-2703. 

The oil solubility of an anaesthetic is of interest, not only because it governs the passage of the anaesthetic into and out of the fat depots of the body, but also because there is a well-established correlation between anaesthetic potency and oil solubility. Figure 2.10 shows a linear inverse relationship between log narcotic concentration and log solubility in oleyl alcohol for a series of common anaesthetic gases. The ordinate of the graph represents the minimum alveolar concentration (MAC), which is that concentration of anaesthetic at which 50% of the patients cease to move in response to a stimulus. The abscissa shows the solubility expressed in terms of the oil/gas partition coefficient. Partition coefficients are widely used to express solubility and are the ratios of the concentration of the gas in the two phases in equilibrium at a given temperature. When, as in this case, one of the phases is the gas itself, the partition coefficient expressed as the liquid/gas (note the order of the phases) concentration ratio is equal to the... 

The toxicity and the affinity of solvents to cell structures increase with hydrophobic properties of solvents, e.g., high toxicities with P, values of l-S. The partition coefficient correlates with the membrane-buffer partition coefficient between membrane and aqueous system. They also depend on membrane characteristics. 

Polarity and solubility are critical to the design and delivery of the drugs used as medicines, an area of chemistry known as medicinal chemistry. The so-called partition coefficient (distribution coefficient) is used as a measure of the ability of the drug to pass through relatively nonpolar lipid membranes from the highly polar environment of blood serum (mostly water). This correlation has been used to predict the activity of potential drugs, but is valid only when solubility and transport by diffusion though a membrane are important. The partition coefficient, P, is defined as... 

Surface area has a prominent effect on the interactions which occur between a drug molecule and its surroundings. When the surface area is introduced as a de.scriptor in chemo-metric analyses, it has been found to contribute. stati.stically significant information in correlations developed for water solubility, octanol-water partition coefficients, activity coefficients and boiling points. " ... 

Note that the relative spatial arrangement of the phenyl, amine, and hydroxyl functionahties are identical for (R)-alprenolol and (5)-sotalol. In addition to P-blocking activities, some of these compounds also possess potent local anaesthetic activity (see Anesthetics). The membrane stabilizing activity, however, is not stereoselective and correlates directly with the partition coefficient (hydrophobicity) of the compound. 

The correlation coefficient for this equation was 0.994. Such a paraboHc dependence of activity on the partition coefficient may reflect partitioning of the dmg through several membrane barriers, which enabled the dmg to reach its site of action. 

In subsequent studies attempting to find a correlation of physicochemical properties and antimicrobial activity, other parameters have been employed, such as Hammett O values, electronic distribution calculated by molecular orbital methods, spectral characteristics, and hydrophobicity constants. No new insight on the role of physiochemical properties of the sulfonamides has resulted. Acid dissociation appears to play a predominant role, since it affects aqueous solubiUty, partition coefficient and transport across membranes, protein binding, tubular secretion, and reabsorption in the kidneys. An exhaustive discussion of these studies has been provided (10). 

Silicones have been detected in water from various rivers and in effluent from wastewater treatment faciUties. They are barely detectable in water from municipal treatment faciUties. Water solubiUty (S) of siUcones has been found to correlate with the octanol—water partition coefficients for a... 

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