Identification of molecular-interaction sites between lowly hydrolyzed polyvinyl alcohols and indomethacin by NMR spectroscopy

Mori, Yoshimasa; Takahashi, Mitsumasa; Yasushi, Ohno; Okura, Ryuhei; Ishida, Makoto; Higashi, Taishi; Motoyama, Keiichi; Arima, Hisatomi

doi:10.1016/j.ijpharm.2018.08.018

Cited by 11 publications

(6 citation statements)

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“…In fact, this particular distribution of acetate moieties has been previously exploited to load hydrophobic molecules inside colloidal particles of PVA ( poly(vinyl acetate)). 57 Such an acetate group distribution can determine the GA partition, based on the polymer nature, which would preferably be within the polymer coils in PVA 88 , while it would be less localized in PVA 98 . Taking into account the overall number of GA molecules (GA t ), added to prepare the supramolecular networks (eqn (3)), two kinds of assembly pathways could be considered.…”

Section: Papermentioning

confidence: 99%

Unraveling the gallol-driven assembly mechanism of thermoreversible supramolecular hydrogels inspired by ascidians

et al. 2020

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Section: Papermentioning

confidence: 99%

Unraveling the gallol-driven assembly mechanism of thermoreversible supramolecular hydrogels inspired by ascidians

et al. 2020

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“…In general, NMR monitors possible changes of electron density around specific interacting atoms to detect molecular interactions at the atomic level [ 88 , 89 ]. For instance, the observation of chemical shifts in 1 H NMR spectra can reveal hydrogen bond formation in SDs [ 90 , 91 , 92 , 93 ]. Typically, the chemical shift is attributed to the change in electron density around the proton caused by hydrogen bond formation [ 91 , 94 ].…”

Section: Spectroscopic Techniques Used In the Investigation Of Molmentioning

confidence: 99%

Molecular Interactions in Solid Dispersions of Poorly Water-Soluble Drugs

Tran

2020

Pharmaceutics

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Physicochemical characterization is a crucial step for the successful development of solid dispersions, including the determination of drug crystallinity and molecular interactions. Typically, the detection of molecular interactions will assist in the explanation of different drug performances (e.g., dissolution, solubility, stability) in solid dispersions. Various prominent reviews on solid dispersions have been reported recently. However, there is still no overview of recent techniques for evaluating the molecular interactions that occur within solid dispersions of poorly water-soluble drugs. In this review, we aim to overview common methods that have been used for solid dispersions to identify different bond formations and forces via the determination of interaction energy. In addition, a brief background on the important role of molecular interactions will also be described. The summary and discussion of methods used in the determination of molecular interactions will contribute to further developments in solid dispersions, especially for quick and potent drug delivery applications.

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“…Since the first 1 H NMR spectra of water and ethanol have been obtained more than 60 years, today there are many works (Batta et al, 1997;Albert, 2002;Meusinger, 2010;Rutledge, 1996;Holzgrabe et al, 2008) [7,12,21,26,29] in which the spectra of water and ethanol are given -which are understandble from the analytical point of view of the substance. But these relatively simple molecules have a large variety of details that occupy a deserved place both in works (Arnold, 2002;Becker et al, 2002;Oliveira et al, 2007;Ababneh, 2018;Richards, Hollerton, 2011;Xu et al, 2012;Mori et al, 2018) [3,4,19,22,27,30,31] and are of interest to our work [15,16].…”

Section: Introductionmentioning

confidence: 99%

Study of internal mechanisms for establishment of the equilibrium state of water-alcohol mixtures in vodka technology

Kuzmin¹,

Zubkova²,

Shendrik³

et al. 2018

Ukr

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Introduction. The aim of the publication is to study the mechanism of the establishment of relaxation of water-alcohol mixtures (WAM) in the main stages of creating vodka in the application of electrochemical activation (ECA) at the stage of Na-cationization process water softening. Materials and methods. 1 H NMR analysis was performed using: FT-NMR Bruker Avance II spectrometer (400 MHz); special capillary with acEtOHe-d6; high accuracy ampoules № 507-HP; dispenser; ethyl alcohol rectified (EAR); water softened by Na-cationization; WAM from EAR and softened water. Results and discussion. In this work, the equilibrium state of vodkas in the creation of WAM in the process of ECA of softened water by Nacationization is investigated. It has been established that electrochemical reactions lead to a change in the system of intermolecular interactions. Charging states of molecules in anolyte and catholyte lead to differences in the electron distribution, which affects the chemical displacements of hydroxyl protons. In relation to the softened water (δH2O=4.65 ppm), the anolyte with δH2O=(4.23; 4.22) ppm has a displacement of the hydroxyl proton in the «strong field» at Δf=170 Hz. The catholyte with δН2О=(4.56; 4.54) ppm has a displacement in the «strong field» at Δf=40 Hz. It has been proved that the WAM on anolyte (pH=2.43) and EAR has an acidic medium (pH=3.10), WAM in a catholyte (pH=11.08), and EAR has a meadow medium (pH=11.75). These polar ratios of H3O + to OHfor anolyte and catholyte lead to a restructuring of the structure in the alcohol/water system. It can be assumed that the proton exchange is accelerated, while there is one general signal of mobile protons EtOH+H2O. On the basis of the study a fundamental difference between the behavior of the WAM and the vodka prepared on softened water and water after ECA treatment was established. Found systems (alcohol/water) with a stable equilibrium, which are characterized by a high degree of generalization of protons, as well as characteristic rates of exchange for it. Conclusions. The experimental data obtained prove the dependence of the speed and nature of the establishment of the thermodynamic equilibrium due to the relaxation of the WAM. It is shown that relaxation occurs at the simultaneous stabilization of the hydroxyl group of water and ethanol protons.

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Identification of molecular-interaction sites between lowly hydrolyzed polyvinyl alcohols and indomethacin by NMR spectroscopy

Cited by 11 publications

References 55 publications

Unraveling the gallol-driven assembly mechanism of thermoreversible supramolecular hydrogels inspired by ascidians

Unraveling the gallol-driven assembly mechanism of thermoreversible supramolecular hydrogels inspired by ascidians

Molecular Interactions in Solid Dispersions of Poorly Water-Soluble Drugs

Study of internal mechanisms for establishment of the equilibrium state of water-alcohol mixtures in vodka technology

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