Erythrocyte ghost – buffer partition coefficients of phenobarbital, pentobarbital, and thiopental support the pH-partition hypothesis

1979 ◽  
Vol 57 (3) ◽  
pp. 325-328 ◽  
Author(s):  
Klaus Korten ◽  
Keith W. Miller
Keyword(s):  
Partition Coefficient ◽  
Organic Solvents ◽  
Partition Coefficients ◽  
Biological Membranes ◽  
Erythrocyte Ghost ◽  
Red Cell ◽  
Data Support ◽  
Permeability Constants ◽  
Degree Of Association

The partition coefficient (λ) between red cell ghosts and buffer has been determined for three barbiturates over a range of pH. Experimental partition coefficients were linearly proportional to the calculated degree of association of the barbiturates. λ was 9.5 ± 0.52 for phenobarbital, 12.7 ± 0.91 for pentobarbital, and 27 ± 4.9 for thiopental in their acid forms. λ for all three barbiturates in their anionic forms was zero. Our data support the assumption of the pH-partition hypothesis that the dependence of λ on pH in biological membranes behaves essentially like that in organic solvents. However, the relative magnitudes of the erythrocyte partition coefficients correlate much more closely with the physiological permeability constants than do those of organic solvents, which tend to overestimate the differences between these compounds.

scholarly journals Membrane solubility of chlorpromazine. Hygroscopic desorption and centrifugation methods yield comparable results

1984 ◽  
Vol 224 (3) ◽  
pp. 1023-1026 ◽  
Author(s):  
M Luxnat ◽  
H J Müller ◽  
H J Galla
Keyword(s):  
Partition Coefficient ◽  
Physical Properties ◽  
Partition Coefficients ◽  
Biological Membranes ◽  
Membrane Composition ◽  
Bilayer Membranes ◽  
Filtration Method ◽  
Centrifugation Method ◽  
Positively Charged

Binding of the positively charged drug chlorpromazine to artificial and erythrocyte bilayer membranes was investigated by the filtration method called hygroscopic desorption [Conrad & Singer (1979) Proc. Natl. Acad. Sci. U.S.A. 76, 5202-5206] and by the conventional centrifugation method. Only minor differences in the partition coefficients were observed using the two methods. Our finding is not consistent with the observation of Conrad & Singer that amphipaths are completely excluded from biological membranes. However, the partition coefficient is dependent on membrane composition, which means dependent on the physical properties of a membrane.

Partition Coefficient Ratios and Tumour Perfusion Studied with 85mKr and 133Xe

1987 ◽  
Vol 26 (06) ◽  
pp. 253-257
Author(s):  
M. Mäntylä ◽  
J. Perkkiö ◽  
J. Heikkonen
Keyword(s):  
Partition Coefficient ◽  
Partition Coefficients ◽  
Regional Blood Flow ◽  
Blood Perfusion ◽  
Compartmental Analysis ◽  
Malignant Tumour ◽  
Mean Value ◽  
Perfusion Rate ◽  
Biological Variables ◽  
The Mean

The relative partition coefficients of krypton and xenon, and the regional blood flow in 27 superficial malignant tumour nodules in 22 patients with diagnosed tumours were measured using the 85mKr- and 133Xe-clearance method. In order to minimize the effect of biological variables on the measurements the radionuclides were injected simultaneously into the tumour. The distribution of the radiotracers was assumed to be in equilibrium at the beginning of the experiment. The blood perfusion was calculated by fitting a two-exponential function to the measuring points. The mean value of the perfusion rate calculated from the xenon results was 13 ± 10 ml/(100 g-min) [range 3 to 38 ml/(100 g-min)] and from the krypton results 19 ± 11 ml/(100 g-min) [range 5 to 45 ml/(100 g-min)]. These values were obtained, if the partition coefficients are equal to one. The equations obtained by using compartmental analysis were used for the calculation of the relative partition coefficient of krypton and xenon. The partition coefficient of krypton was found to be slightly smaller than that of xenon, which may be due to its smaller molecular weight.

Interphase distribution of 2-furylethylenes

1985 ◽  
Vol 50 (8) ◽  
pp. 1642-1647 ◽  
Author(s):  
Štefan Baláž ◽  
Anton Kuchár ◽  
Ernest Šturdík ◽  
Michal Rosenberg ◽  
Ladislav Štibrányi ◽  
...  
Keyword(s):  
Partition Coefficient ◽  
Partition Coefficients ◽  
Transport Rate ◽  
Phase System ◽  
Two Phase ◽  
Interphase Distribution ◽  
Distribution Kinetics ◽  
System 1 ◽  
Kinetics Of

The distribution kinetics of 35 2-furylethylene derivatives in two-phase system 1-octanol-water was investigated. The transport rate parameters in direction water-1-octanol (l1) and backwards (l2) are partition coefficient P = l1/l2 dependent according to equations l1 = logP - log(βP + 1) + const., l2 = -log(βP + 1) + const., const. = -5.600, β = 0.261. Importance of this finding for assesment of distribution of compounds under investigation in biosystems and also the suitability of the presented method for determination of partition coefficients are discussed.

Apparent octanol/water partition coefficients of pentachlorophenol as a function of pH

1982 ◽  
Vol 60 (16) ◽  
pp. 2104-2106 ◽  
Author(s):  
Klaus L. E. Kaiser ◽  
Ilze Valdmanis
Keyword(s):  
Aqueous Solution ◽  
Ionic Strength ◽  
Partition Coefficient ◽  
Linear Function ◽  
Partition Coefficients ◽  
Extreme Values ◽  
Log P ◽  
Water Partition Coefficient ◽  
Non Linear ◽  
Good Agreement

The apparent 1-octanol/water partition coefficient (log PApp) of pentachlorophenol (PCP) varies in non-linear function with pH of the aqueous solution. In the range of pH 1.2 to 13.5 extreme values of log PApp 4.84 at pH 1.2 and log PApp 1.3 at pH 10.5 were observed. In the alkaline regime, log PApp increases strongly with the ionic strength. The ion-corrected partition coefficient of PCP was found to be log P 5.05 in good agreement with literature values.

scholarly journals Calculating the Partition Coefficients of Organic Solvents in Octanol/Water and Octanol/Air

2019 ◽  
Vol 59 (5) ◽  
pp. 2257-2263 ◽  
Author(s):  
Miroslava A. Nedyalkova ◽  
Sergio Madurga ◽  
Marek Tobiszewski ◽  
Vasil Simeonov
Keyword(s):  
Organic Solvents ◽  
Partition Coefficients

Partitioning of charged and neutral dextran-dye derivatives in biphasic cellulose nanocrystal suspensions

2008 ◽  
Vol 86 (6) ◽  
pp. 503-511 ◽  
Author(s):  
Stephanie Beck-Candanedo ◽  
David Viet ◽  
Derek G Gray
Keyword(s):  
Molecular Weight ◽  
Partition Coefficient ◽  
Cellulose Nanocrystals ◽  
Partition Coefficients ◽  
Virial Coefficient ◽  
Total Concentration ◽  
Second Virial Coefficient ◽  
Fluorescein Isothiocyanate ◽  
Blue Dextran ◽  
Molecular Weights

The partitioning behaviour of dye-labeled dextrans of high molecular weight in aqueous suspensions of native cellulose nanocrystals was studied. Cellulose concentrations lie in the isotropic–nematic coexistence region. Blue dextrans of various molecular weights and degrees of substitution of dye molecules (anionic Cibacron blue 3G-A) were investigated. Increasing the total concentration of blue dextran and degree of dye substitution led to increasing partition coefficients. Increasing dextran molecular weight resulted in higher partition coefficients, in agreement with theory. Partition coefficients were larger than predicted theoretically using a second virial coefficient approximation. Electrostatic and entropic contributions to the partition coefficient of blue dextran are discussed. Dextrans labeled with neutral fluorescein isothiocyanate did not partition preferentially in this system.Key words: partition coefficient, cellulose nanocrystals, dextrans, degree of substitution, polyelectrolyte.

Force Field Benchmark of Amino Acids. 2. Partition Coefficients between Water and Organic Solvents

2018 ◽  
Vol 58 (8) ◽  
pp. 1669-1681 ◽  
Author(s):  
Haiyang Zhang ◽  
Yang Jiang ◽  
Ziheng Cui ◽  
Chunhua Yin
Keyword(s):  
Amino Acids ◽  
Force Field ◽  
Organic Solvents ◽  
Partition Coefficients

scholarly journals Tracer Determinations of Human Red Cell Membrane Permeability to Small Nonelectrolytes

1971 ◽  
Vol 58 (3) ◽  
pp. 259-266 ◽  
Author(s):  
David Savitz ◽  
A. K. Solomon
Keyword(s):  
Cell Membrane ◽  
Partition Coefficient ◽  
Cell Membrane Permeability ◽  
Red Cell ◽  
Red Cell Membrane ◽  
Water Partition Coefficient ◽  
Order Of Magnitude ◽  
Red Cell Membranes ◽  
Human Red Cell Membrane ◽  
Good Agreement

A flow system has been used to determine the permeability of human red cell membranes to four small nonelectrolytes labeled with 14C. The permeability coefficients, ω, in units of mol dyne-1 sec-1 x 1015, are: ethylene glycol, 6; urea, 13; formamide, 22; and methanol, 131. The values for urea and formamide are in good agreement with values obtained by Sha'afi, Gary-Bobo, and Solomon by the minimum method. The unusually high value for ω for methanol is ascribed to its solubility in the red cell membrane since its ether: water partition coefficient is 0.14, higher by more than an order of magnitude than the ether: water partition coefficient for water. The other three solutes are hydrophilic and are characterized by values of ω which behave consistently with those of other hydrophilic amides and ureas. The values of ω for the three hydrophilic solutes measured are also consistent with an equivalent pore radius of about 3.5 A in agreement with previous estimates made on the basis of other types of studies.

Age-Dependent Partition Coefficients for a Mixture of Volatile Organic Solvents in Sprague-Dawley Rats and Humans

2007 ◽  
Vol 70 (20) ◽  
pp. 1745-1751 ◽  
Author(s):  
Deirdre A. Mahle ◽  
Jeffery M. Gearhart ◽  
Claude C. Grigsby ◽  
David R. Mattie ◽  
Hugh A. Barton ◽  
...  
Keyword(s):  
Organic Solvents ◽  
Partition Coefficients ◽  
Sprague Dawley ◽  
Sprague Dawley Rats ◽  
Volatile Organic ◽  
Age Dependent
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