Improving single-step scCO2 dyeing of wood by DMSO-induced micro-swelling

Jaxel, Julien; Gusenbauer, Claudia; Böhmdorfer, Stefan; Liebner, Falk; Hansmann, Christian

doi:10.1016/j.supflu.2020.104978

Cited by 10 publications

(5 citation statements)

References 45 publications

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“…This ensures acceptable purity of the micronized particles and avoids the formation of co-solvents with DMSO. It should be noted that scCO2 + DMSO-d6 can be in a subcritical state at these state parameters [41,43].…”

Section: Methodsmentioning

confidence: 96%

“…Choice of these particular parameters of state is justified by the fact that increasing the pressure to 10 MPa at the same temperature of 45 °C brings the system scCO2 + DMSO-d6 to the critical point [43]. It is accompanied by substantial density fluctuations with minimal variations of pressure, and NMR spectra of high quality cannot be recorded any more.…”

Section: Influence Of Hidden Conformers Of Mfa In Scco2mentioning

confidence: 99%

“…Comparison of the results shown in Figure 10 leads us to a conclusion that the error in determining the conformer fractions in the case of the mixed solvent is also very large, exceeding 50%. Thus, using the model of two-position chemical exchange given by Equation ( 6) and allowing for the additional conformers, we plotted the dependences of Choice of these particular parameters of state is justified by the fact that increasing the pressure to 10 MPa at the same temperature of 45 • C brings the system scCO 2 + DMSO-d 6 to the critical point [43]. It is accompanied by substantial density fluctuations with minimal variations of pressure, and NMR spectra of high quality cannot be recorded any more.…”

Section: Influence Of Hidden Conformers Of Mfa In Sccomentioning

confidence: 99%

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The Role of Hidden Conformers in Determination of Conformational Preferences of Mefenamic Acid by NOESY Spectroscopy

et al. 2022

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Mefenamic acid has been used as a non-steroidal anti-inflammatory drug for a long time. However, its practical use is quite limited due to a number of side effects on the intestinal organs. Conformational polymorphism provides mefenamic acid with unique properties regarding possible modifications obtained during the micronization process, which can improve pharmacokinetics and minimize side effects. Micronization can be performed by decompression of supercritical fluids; methods such as rapid expansion of the supercritical solution have proven their efficiency. However, this group of methods is poorly applicable for compounds with low solubility, and the modification of the method using a pharmaceutically suitable co-solvent may be useful. In our case, addition of only 2 mol % dimethyl sulfoxide increased the solubility remarkably. Information on the conformational state may be critically important for carrying out micronization. In this work, structural analysis and estimate of conformational preferences of mefenamic acid in dimethyl sulfoxide − d6 (at 25 °C and 0.1 MPa) and in a mixed solvent supercritical carbon dioxide + dimethyl sulfoxide-d6 (45 °C, 9 MPa) were performed based on nuclear Overhauser effect spectroscopy. Results show changes in the conformation fractions depending on the medium used. The importance of allowing for hidden conformers in estimating the conformational state was demonstrated in the analysis. Obtained results may be useful for improving micronization parameters.

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Section: Methodsmentioning

confidence: 96%

Section: Influence Of Hidden Conformers Of Mfa In Scco2mentioning

confidence: 99%

Section: Influence Of Hidden Conformers Of Mfa In Sccomentioning

confidence: 99%

See 1 more Smart Citation

The Role of Hidden Conformers in Determination of Conformational Preferences of Mefenamic Acid by NOESY Spectroscopy

et al. 2022

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“…This setup was linked to a Bruker Avance III 500 spectrometer (Bruker Biospin, Karlsruhe, Baden-Württemberg, Germany) and a high pressure NMR cell (Daedalus Innovations LLC, Aston, PA, USA) recording the NMR spectra at given parameters of state exceeding the critical point for CO 2 (45 °C and 9 MPa). At such pressure and temperature values, the SC-CO 2 + DMSO-d 6 mixture can be in a subcritical state [ 52 , 56 , 57 ].…”

Section: Methodsmentioning

confidence: 99%

Investigation of the Spatial Structure of Flufenamic Acid in Supercritical Carbon Dioxide Media via 2D NOESY

et al. 2023

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The search for new forms of already known drug compounds is an urgent problem of high relevance as more potent drugs with fewer side effects are needed. The trifluoromethyl group in flufenamic acid renders its chemical structure differently from other fenamates. This modification is responsible for a large number of conformational polymorphs. Therefore, flufenamic acid is a promising structural modification of well-known drug molecules. An effective approach in this field is micronization, employing “green” supercritical fluid technologies. This research raises some key questions to be answered on how to control polymorphic forms during the micronization of drug compounds. The results presented in this work demonstrate the ability of two-dimensional nuclear Overhauser effect spectroscopy to determine conformational preferences of small molecular weight drug compounds in solutions and fluids, which can be used to predict the polymorphic form during the micronization. Quantitative analysis was carried out to identify the conformational preferences of flufenamic acid molecules in dimethyl sulfoxide-d6 medium at 25 °C and 0.1 MPa, and in mixed solvent medium containing supercritical carbon dioxide at 45 °C and 9 MPa. The data presented allows predictions of the flufenamic acid conformational preferences of poorly soluble drug compounds to obtain new micronized forms.

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“…Then, 86 μL of a solution of mefenamic acid in DMSO-d 6 was added to the ampoule, followed by filling the remaining volume of the ampoule with carbon dioxide from a gas cylinder (see Figure 8 ). The selection of state parameters (45 °C and 9 MPa) and the required amount of mefenamic acid solution in DMSO-d 6 for recording NOESY spectra was based on the data of works [ 85 , 95 , 96 ].…”

Section: Methodsmentioning

confidence: 99%

Exploring the Conformational Equilibrium of Mefenamic Acid Released from Silica Aerogels via NMR Analysis

Khodov

Sobornova

Mulloyarova

et al. 2023

IJMS

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This study examines the influence of mefenamic acid on the physical and chemical properties of silica aerogels, as well as its effect on the sorption characteristics of the composite material. Solid state magic angle spinning nuclear magnetic resonance (MAS NMR) and high-pressure 13C NMR kinetic studies were conducted to identify the presence of mefenamic acid and measure the kinetic rates of CO2 sorption. Additionally, a high-pressure T1–T2 relaxation-relaxation correlation spectroscopy (RRCOSY) study was conducted to estimate the relative amount of mefenamic acid in the aerogel’s pores, and a high-pressure nuclear Overhauser effect spectoscopy (NOESY) study was conducted to investigate the conformational preference of mefenamic acid released from the aerogel. The results indicate that mefenamic acid is affected by the chemical environment of the aerogel, altering the ratio of mefenamic acid conformers from 75% to 25% in its absence to 22% to 78% in the presence of aerogel.

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Improving single-step scCO2 dyeing of wood by DMSO-induced micro-swelling

Cited by 10 publications

References 45 publications

The Role of Hidden Conformers in Determination of Conformational Preferences of Mefenamic Acid by NOESY Spectroscopy

The Role of Hidden Conformers in Determination of Conformational Preferences of Mefenamic Acid by NOESY Spectroscopy

Investigation of the Spatial Structure of Flufenamic Acid in Supercritical Carbon Dioxide Media via 2D NOESY

Exploring the Conformational Equilibrium of Mefenamic Acid Released from Silica Aerogels via NMR Analysis

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