scholarly journals Role of stable hydrogen isotope variations in water for drug dissolution managing

2020 ◽  
Vol 33 (2) ◽  
pp. 94-101
Author(s):  
Elena V. Uspenskaya ◽  
Tatyana V. Pleteneva ◽  
Anton V. Syroeshkin ◽  
Ilaha V. Kazimova ◽  
Tatyana E. Elizarova ◽  
...  
Keyword(s):  
Hydrogen Isotope ◽  
Water Solubility ◽  
Vibrational Energy ◽  
Isotopic Effect ◽  
Drug Dissolution ◽  
Log P ◽  
Dispersion Phase ◽  
Kinetic Isotopic Effect ◽  
Pharmaceutical Industries ◽  
Stable Hydrogen Isotope

AbstractIn the present work, we provide the results of defining by utilizing Laser diffraction spectroscopy, the kinetic isotopic effect of solvent and constant of dissolution rate κ, s−1 of аn active pharmaceutical ingredient (API) in water with a different content of a stable _2^1{\rm{H}} isotope on the basis of the laws of first-order kinetics. This approach is based on the analysis of the light scattering profile that occurs when the particles of the dispersion phase in the aquatic environment are covered with a collimated laser beam. For the first time, the dependence of the rate of dissolution is demonstrated not only on the properties of the pharmaceutical substance itself (water solubility mg/ml, octanol–water partition coefficient log P oct/water, topological polar surface area, Abraham solvation parameters, the lattice type), but also on the properties of the solvent, depending on the content of stable hydrogen isotope. We show that the rate constant of dissolution of a sparingly hydrophobic substance moxifloxacin hydrochloride (MF · HCl) in the Mili-Q water is: k=1.20±0.14∙10−2 s−1 at 293.15 K, while in deuterium depleted water, it is k=4.24±0.4∙10−2 s−1. Consequently, we have established the development of the normal kinetic isotopic effect (kH/kD >1) of the solvent. This effect can be explained both by the positions of the difference in the vibrational energy of zero levels in the initial and transition states, and from the position of water clusters giving volumetric effects of salvation, depending on the ratio D/H. The study of kinetic isotopic effects is a method that gives an indication of the mechanism of reactions and the nature of the transition state. The effect of increasing the dissolution of the API, as a function of the D/H ratio, we have discovered, can be used in the chemical and pharmaceutical industries in the study of API properties and in the drug production through improvement in soluble and pharmacokinetic characteristics.

Quantitative Structure-Property Relationship (QSPR) Study of the Hydrophobicity of Phenols and 2-(Aryloxy-a-acetyl)-phenoxathiin Derivatives

2008 ◽  
Vol 59 (11) ◽  
Author(s):  
Adrian Beteringhe ◽  
Ana Cristina Radutiu ◽  
Titus Constantinescu ◽  
Luminita Patron ◽  
Alexandru T. Balaban
Keyword(s):  
Water Solubility ◽  
Molecular Descriptors ◽  
Log P ◽  
Structure Property ◽  
Substituted Phenols ◽  
Reverse Phase ◽  
Aromaticity Index ◽  
Structure Property Relationship ◽  
Layer Chromatography ◽  
Energy Of Formation

In a preceding study, the molecular hydrophobicity (RM0) was determined experimentally from reverse-phase thin-layer chromatography data for several substituted phenols and 2-(aryloxy-a-acetyl)-phenoxathiin derivatives, obtained from the corresponding phenoxides and 2-(a-bromoacetyl)-phenoxathiin. QSPR correlations for RM0 were explored using four calculated molecular descriptors: the water solubility parameter (log Sw), log P, the Gibbs energy of formation (DGf), and the aromaticity index (HOMA). Triparametric correlations do not improve substantially the biparametric correlation of RM0 in terms of log Sw and HOMA.

scholarly journals Estimation of the retention behaviour of s-triazine derivatives applying multiple regression analysis of selected molecular descriptors

2013 ◽  
pp. 229-237 ◽  
Author(s):  
Lidija Jevric ◽  
Sanja Podunavac-Kuzmanovic ◽  
Strahinja Kovacevic ◽  
Natasa Kalajdzija ◽  
Bratislav Jovanovic
Keyword(s):  
Dissociation Constant ◽  
Water Solubility ◽  
Molecular Descriptors ◽  
Chemical Properties ◽  
Log P ◽  
Retention Factors ◽  
Solute Retention ◽  
Physico Chemical ◽  
Hydrophilic Lipophilic Balance ◽  
Triazine Derivatives

The estimation of retention factors by correlation equations with physico-chemical properties can be of great helpl in chromatographic studies. The retention factors were experimentally measured by RP-HPTLC on impregnated silica gel with paraffin oil using two-component solvent systems. The relationships between solute retention and modifier concentration were described by Snyder?s linear equation. A quantitative structure-retention relationship was developed for a series of s-triazine compounds by the multiple linear regression (MLR) analysis. The MLR procedure was used to model the relationships between the molecular descriptors and retention of s-triazine derivatives. The physicochemical molecular descriptors were calculated from the optimized structures. The physico-chemical properties were the lipophilicity (log P), connectivity indices (?), total energy (Et), water solubility (log W), dissociation constant (pKa), molar refractivity (MR), and Gibbs energy (GibbsE) of s-triazines. A high agreement between the experimental and predicted retention parameters was obtained when the dissociation constant and the hydrophilic-lipophilic balance were used as the molecular descriptors. The empirical equations may be successfully used for the prediction of the various chromatographic characteristics of substances, with a similar chemical structure.

scholarly journals Mass spectrometric measurement of hydrogen isotope fractionation for the reactions of chloromethane with OH and Cl

2018 ◽  
Author(s):  
Frank Keppler ◽  
Enno Bahlmann ◽  
Markus Greule ◽  
Heinz Friedrich Schöler ◽  
Julian Wittmer ◽  
...  
Keyword(s):  
Hydrogen Isotope ◽  
Isotope Fractionation ◽  
Isotope Effects ◽  
Isotope Analysis ◽  
Isotope Ratio Mass Spectrometry ◽  
Detailed Knowledge ◽  
Mass Spectrometric Measurement ◽  
Isotopic Analyses ◽  
Chlorine Radicals ◽  
Stable Hydrogen Isotope

Abstract. Chloromethane (CH3Cl) is an important provider of chlorine to the stratosphere but yet lacks detailed knowledge of its budget. Stable isotope analysis is potentially a powerful tool to constrain CH3Cl flux estimates. The largest degree of isotope fractionation is expected to occur for deuterium in CH3Cl in the hydrogen abstraction reactions with its main sink reactant tropospheric OH and its minor sink reactant Cl atoms. We determined the isotope fractionation by stable hydrogen isotope analysis of the fraction of CH3Cl remaining after reaction with hydroxyl and chlorine radicals in a 3.5 m3 Teflon smog-chamber at 293 ± 1 K. We measured the increasing stable hydrogen isotope values of the unreacted CH3Cl using compound specific thermal conversion isotope ratio mass spectrometry. The isotope fractionations of CH3Cl for the reactions with hydroxyl and chlorine radicals were found to be −242 ± 7 mUr (or ‰) and −280 ± 11 mUr, respectively. For comparison, we performed similar experiments using methane (CH4) as the target compound with OH and obtained a fractionation constant of −205 ± 6 mUr which is in good agreement with values previously reported. The observed large kinetic isotope effects are helpful when employing isotopic analyses of CH3Cl in the atmosphere to improve our knowledge of its atmospheric budget.

scholarly journals A study of the effects of sodium alginate and sodium carboxymethyl cellulose on the growth of the common duckweed (Lemna minor L.)

2021 ◽  
pp. 82-82
Author(s):  
Bianca Boros ◽  
Nathalie Grau ◽  
Adriana Isvoran ◽  
Adina Datcu ◽  
Nicoleta Ianovici ◽  
...  
Keyword(s):  
Sodium Alginate ◽  
Carboxymethyl Cellulose ◽  
Water Solubility ◽  
Lemna Minor ◽  
Sodium Carboxymethyl Cellulose ◽  
Log P ◽  
Growth Inhibitory ◽  
Wide Range ◽  
The Common ◽  
High Doses

Sodium alginate (ALG) and sodium carboxymethyl cellulose (CMC) are two polysaccharides that have a wide range of applications which could lead to accidental pollution of the environment, making the assessment of their potential ecotoxicity imperative. The present study assesses the ALG and CMC effects on the growth response of the common duckweed (Lemna minor L.). The results emphasize that both polysaccharides can be classified as practically nontoxic based on their EC50 values, with ALG having a relatively higher toxicity compared to CMC. It was also observed that high doses of 1, 5 and 10 mg mL-1 of the two polysaccharides produced growth inhibitory effects against common duckweed. The toxicity of biopolymers against common duckweed, measured as EC50 values, seems to be correlated to the hydrophobicity of the monomers building the polymer. The EC50 values increase linearly with the increase of water solubility (log S) values and decrease linearly with the lipophilicity (log P) values.

scholarly journals Round-trip across the Sahara: Afrotropical Painted Lady butterflies recolonize the Mediterranean in early spring

2018 ◽  
Vol 14 (6) ◽  
pp. 20180274 ◽  
Author(s):  
Gerard Talavera ◽  
Clément Bataille ◽  
Dubi Benyamini ◽  
Martin Gascoigne-Pees ◽  
Roger Vila
Keyword(s):  
Hydrogen Isotope ◽  
Migratory Birds ◽  
Early Spring ◽  
Round Trip ◽  
Reverse Migration ◽  
Vanessa Cardui ◽  
Tangible Evidence ◽  
Stable Hydrogen Isotope ◽  
Sub Saharan ◽  
Work Supports

The Palearctic–African migratory circuit has been typically associated with birds. Very few insects are known to endure annual trans-Saharan circuits, but the Painted Lady butterfly ( Vanessa cardui ) is an exception. While it was demonstrated that this species massively migrates from Europe to the Afrotropics during the autumn, the existence of a reverse migration from the Afrotropics to Europe in the early spring remains hypothetical. Here, we analysed wing stable hydrogen isotope values (δ 2 H) of V. cardui migrants collected from February to April across the circum-Mediterranean region. We assessed their region of natal origin by comparing their wing isotope signature predicted δ 2 H values (isoscape). The results unambiguously demonstrate a sub-Saharan origin for many individuals, especially those collected in February, representing the first tangible evidence for a reverse northwards trans-Saharan migration in spring. This work supports the view that the Afrotropics (mostly exploited from September to February) is key in the V. cardui Palearctic–African population dynamics. This species relies on both temperate and tropical habitats to complete their multigenerational cycle, an unprecedented adaptation for butterflies and for most migratory insects. Such a migratory circuit has strong parallelisms with those of migratory birds.

scholarly journals Stable Isotope Evidence Links Breeding Geography and Migration Timing in Wood Warblers (Parulidae)

The Auk ◽  
2006 ◽  
Vol 123 (2) ◽  
pp. 431-437 ◽  
Author(s):  
Jeffrey F. Kelly
Keyword(s):  
Hydrogen Isotope ◽  
Life Histories ◽  
Isotope Ratios ◽  
Interspecific Variation ◽  
Autumn Migration ◽  
Breeding Sites ◽  
Migration Timing ◽  
Wood Warblers ◽  
Stable Hydrogen Isotope ◽  
Hydrogen Isotope Ratios

AbstractTracking seasonal movements of songbirds is a key step in understanding the annual cycle of migrants. To better understand autumn migration of wood warblers, I analyzed stable-hydrogen isotope ratios of feathers collected from three species captured during stopover at the Bosque del Apache National Wildlife Refuge, New Mexico. To assess the form and strength of the relationship between timing of migration and breeding origins, I regressed stable-hydrogen isotope ratios of feathers against date of capture. These analyses indicated that Orange-crowned Warblers (Vermivora celata) and Common Yellowthroats (Geothlypis trichas) breeding in the southern portion of these species' ranges precede their northern conspecifics in autumn migration. By contrast, Yellow Warblers (Dendroica petechia) from northern breeding sites arrived before more southerly breeding conspecifics. This pattern is similar to that reported previously in Wilson's Warbler (Wilsonia pusilla). These findings suggest that, among wood warblers, (1) timing of autumn migration is often strongly related to breeding location and (2) interspecific variation in the direction of this relationship is large. The direction and strength of these patterns have implications for our understanding of inter- and intraspecific geographic variation in the life histories of migrants.Evidencia de Isótopos Estables Conecta la Geografía de Nidificación con el Momento de la Migración en Especies de Parulidae

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