Theoretically consistent calculation of viscous activation parameters through the Eyring equation and their interpretation

Santos, Lucas J. dos; Espinoza-Velasquez, Luis Alonso; Coutinho, João A. P.; Monteiro, Simone Borges Simão

doi:10.1016/j.fluid.2020.112774

Cited by 11 publications

(8 citation statements)

References 46 publications

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“…At the same time, the release parameters of PG increase sharply, and the release parameters of M400 decrease sharply (Fig. 9,10). With an increase in the PG concentration above 75 mol %, it was found that the greater the difference in the concentrations of PG and M400, the greater the difference in the release parameters of PG and M400.…”

Section: Discussion Of Research Resultsmentioning

confidence: 84%

“…The kinematic viscosity and density of the solvents should be determined, and their dynamic viscosity should be calculated in the temperature range from 293.15 K to 313.15 K, in particular, at 25 °C, 32 °C, and 37 °C (storage temperature, temperatures when using medicines in dermatology, as well as in proctology and gynaecology, respectively). The parameters of viscous flow activation: Gibbs free energies, entropy and enthalpy values should be calculated [9]. Excess density, excess dynamic viscosity, and excess activation parameters of viscous flow should be calculated, and possible intermolecular interactions between components in binary solvents, depending on their composition, should be evaluated.…”

Section: Planning (Methodology) Of the Researchmentioning

confidence: 99%

“…One of the elementary acts of the process of viscous flow of associated liquids is the movement of individual molecules, which requires the breaking of a certain number of hydrogen bonds [9]. A certain free activation energy of viscous flow ( )…”

Section: Study Of Some Physicochemical Properties Of Solventsmentioning

confidence: 99%

“…For example, in mixed solvents, N-MP -water, the solubility of meloxicam increases sharply with an increase in the N-MP concent above 70 % w/w, when the structure of the mixed solvent with a predominance of the structure of a non-aqueous solvent prevails [7,8]. In this regard, the study of mixed solvents can be carried out in two directions: first, the study of the properties and structure of mixed solvents depending on their composition [9], and second, the study of their performance characteristics.…”

Section: Introductionmentioning

confidence: 99%

“…Thus, to study the mixed solvents, polythermal determination of parameters (density, dynamic viscosity, ultrasonic speed, etc.) should be performed, which makes it possible to calculate quasi-thermodynamic functions [9]. The determination should be carried out over the entire range of mole fractions, and excess parameters should be calculated [7,10].…”

Section: Introductionmentioning

confidence: 99%

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Influence of physicochemical properties and structure of mixed solvents propylene glycol – macrogol 400 on their in vitro release

Bezuglaya

Krasnopyorova

Liapunova

et al. 2023

SR: PS

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Aim. To study the density and dynamic viscosity of the mixed solvents propylene glycol (PG) – macrogol 400 (M400), to calculate their excess values and excess activation parameters of viscous flow, to evaluate the features of the structure of the mixed solvents and its influence on the in vitro release of PG and M400. Materials and methods. The mixed solvents PG - M400 were studied over the entire concentration range at temperatures from 293.15 to 313.15 K. The density and dynamic viscosity were determined, and the excess density, excess dynamic viscosity, activation parameters of viscous flow, and excess activation parameters of viscous flow were calculated. The in vitro release of PG and M400 from the mixed solvents was studied using vertical diffusion cells. The content of PG and M400 in the receptor medium was determined by gas chromatography using validated analytical procedures. The release rate, cumulative content, percentage of released PG or M400, coefficients of correlation and coefficients of determination were calculated. Results. The isotherms of excess density and excess dynamic viscosity of the mixed solvents PG-M400 pass through a maximum. The enthalpy makes the main contribution to the free activation energy of the viscous flow. The excess free energy is positive and has small values; the values of the excess entropy and excess enthalpy are negative, and the isotherms have the minimum at PG concentrations of 70‑75mol %. The release parameters of M400 are greater in binary mixtures where the M400 structure predominates. At PG content of ~75 mol %, the release parameters for PG and M400 are identical. With the increase in PG content above 75 mol %, when the PG structure predominates in the system, the release parameters of PG increase dramatically, and the release parameters of M400 decrease sharply. Conclusions. The structure of the binary system PG – M400 depends on its composition. Based on the isotherms of excess activation of viscous flow, it is possible to differentiate the areas where the structure of PG or the structure of M400 dominates, or the mixed structure of the binary solvent prevails. The in vitro release parameters for PG and M400 depend on the structure of the mixed solvents. The greatest difference in the release parameters of PG and M400 was observed in the area where the structure of PG dominates

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Section: Discussion Of Research Resultsmentioning

confidence: 84%

Section: Planning (Methodology) Of the Researchmentioning

confidence: 99%

Section: Study Of Some Physicochemical Properties Of Solventsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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