Determination simultanee de l'enthalpie, de l'enthalpie libre via le coefficient de partage et de l'entropie de transfert eau/n-octanol de l'ephedrine par titrimetrie thermometrique

Burgot, Gwenola; Burgot, Jean‐Louis

doi:10.1016/0040-6031(84)85119-9

Cited by 15 publications

(7 citation statements)

References 31 publications

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“…44 An analogous thermometric titration proce-'e, based on the enthalpy of protonation of an amine, has ) been used. 72 A statistical analysis for a correlation between loga-Lms of octanol-water and cyclohexane-water partition co-;ients was carried out by Seiler 73 for 230 compounds. A ~ar relation was found, and the intercept included a term resenting hydrogen bonding by the solute.…”

Section: B Generator Column Methodsmentioning

confidence: 99%

Octanol-Water Partition Coefficients of Simple Organic Compounds

Sangster¹

1989

Journal of Physical and Chemical Reference Data

848

616

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Octanol-water partition coefficients (log P) for 611 simple organic compounds representing all principal classes have been retrieved from the literature. Available experimental details of measurement are documented from original articles. Pertinent thermodynamic relations are presented, with a discussion of direct and indirect methods of measurement. Reported log P data for each compound have been evaluated according to stated criteria, and recommended values (with uncertainty) are given.

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Section: B Generator Column Methodsmentioning

confidence: 99%

Octanol-Water Partition Coefficients of Simple Organic Compounds

Sangster¹

1989

Journal of Physical and Chemical Reference Data

848

616

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Section: Methodsmentioning

confidence: 99%

“…Given that the study solutions were quite dilute, changes in enthalpy and entropy were normalized in relation to changes in the corresponding standard potentials [4]. The thermodynamic potentials of the transition of polyuronides were calculated using standard equations: DH°using the Van't Hoff equation (1), DS°using equation (2), DG°using the Gibbs-Helmholz equation (3) and using partition coefficients (4) [4,5]:…”

Section: Methodsmentioning

confidence: 99%

“…The thermodynamic potentials of the transition of polyuronides were calculated using standard equations: DH°using the Van't Hoff equation (1), DS°using equation (2), DG°using the Gibbs-Helmholz equation (3) and using partition coefficients (4) [4,5]:…”

Section: Methodsmentioning

confidence: 99%

“…Equilibrium concentrations of polyuronides and their salts in the nonpolar solvent layer (C 2 ) were calculated as the difference between C 0 and C 1 . Calculations [4,5] were made to determine changes in thermodynamic functions: enthalpy (DH°), entropy (DS°), Gibbs free energy (isobaric-isothermic potential DG°), and the entropy component (T. DS°) accompanying the interphase partition of polyuronides.The system consisting of two immiscible solvents was a mixture of water and octan-1-ol, in which water was the model for hydrophilic and octan-1-ol was the model for hydrophobic biological substrates. Octan-1-ol was selected among other nonpolar solvents (butan-1-ol, butan-2-ol, pentan-1-ol, pentan-3-ol, butyl acetate, heptane, xylene) because of the optimum ratio of its hydrophobic and lipophilic properties [2].…”

mentioning

confidence: 99%

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Studies of the Interphase Distribution of Polyuronides in a System Consisting of Two Immiscible Solvents

Kaisheva

Kaishev

2014

Pharm Chem J

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Partition coefficients of polyuronides and their salts (pectin, sodium alginate, calcium alginate) in a water/octan-1-ol system were measured at different temperatures and different pH values. Changes in the thermodynamic functions accompanying interphase partition (enthalpy, entropy, Gibbs free energy) were identified to evaluate the potential for distribution to occur spontaneously.The importance of developing drugs acting as enterosorbents for heavy metals and radionuclides arises from the difficult ecological situation associated with the widespread use of atomic energy, radioactive isotopes, and heavy metals in various areas of industry. Potential antidotes with high efficacy and biological compatibility with the human body include polyuronides (acid polysaccharides), i.e., pectins and alginates [1]. Introduction of these substances into pharmaceutical practice as therapeutic agents with detoxifying properties requires studies of their pharmacokinetic properties, as one of the key points in assessment of biological actions is how substances distribute in biological substrates, as this determines their absorption and the selectivity of their interactions with biological structures. Initial predictions for assessment of pharmacokinetic properties are provided by studies of the interphase partition of study compounds in in vitro experiments, and this defined the present studies.The aim of the present work was to study the partition of polyuronides in a system consisting of two immiscible liquids to predict the accumulation of polyuronides in hydrophilic and hydrophobic biological substrates. EXPERIMENTAL SECTIONPartition coefficients (C p ) were measured as the ratio of the concentrations of polyuronides or their salts in the layers of polar and nonpolar solvents, allowing for the degree of association of the substances (n). [2]. Analysis of the initial (C 0 ) and equilibrium (C 1 ) concentrations of polyuronides in the aqueous medium were measured by acid-base titration [3]; concentrations of polyuronide calcium salts were measured by compleximetric titration [3]. Equilibrium concentrations of polyuronides and their salts in the nonpolar solvent layer (C 2 ) were calculated as the difference between C 0 and C 1 . Calculations [4,5] were made to determine changes in thermodynamic functions: enthalpy (DH°), entropy (DS°), Gibbs free energy (isobaric-isothermic potential DG°), and the entropy component (T. DS°) accompanying the interphase partition of polyuronides.The system consisting of two immiscible solvents was a mixture of water and octan-1-ol, in which water was the model for hydrophilic and octan-1-ol was the model for hydrophobic biological substrates. Octan-1-ol was selected among other nonpolar solvents (butan-1-ol, butan-2-ol, pentan-1-ol, pentan-3-ol, butyl acetate, heptane, xylene) because of the optimum ratio of its hydrophobic and lipophilic properties [2]. The pH values of the prepared aqueous sodium alginate (Na-I) solution (0.02 -0.30 mM), beet pectin (II) (0.02 -0.11 mM), calcium pectinate (Ca...

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ChemInform Abstract: Gleichzeitige, titrimetrisch‐thermometrische Bestimmung der Enthalpie, der Freien Enthalpie via Trennnngskoeffizient und der Entropie des Übergangs Wasser/Octanol von Ephedrin.

Burgot¹,

Burgot²

1985

Chemischer Informationsdienst

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Determination simultanee de l'enthalpie, de l'enthalpie libre via le coefficient de partage et de l'entropie de transfert eau/n-octanol de l'ephedrine par titrimetrie thermometrique

Cited by 15 publications

References 31 publications

Octanol-Water Partition Coefficients of Simple Organic Compounds

Octanol-Water Partition Coefficients of Simple Organic Compounds

Studies of the Interphase Distribution of Polyuronides in a System Consisting of Two Immiscible Solvents

ChemInform Abstract: Gleichzeitige, titrimetrisch‐thermometrische Bestimmung der Enthalpie, der Freien Enthalpie via Trennnngskoeffizient und der Entropie des Übergangs Wasser/Octanol von Ephedrin.

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