Determination of Anthraquinone Violet 3RN solubility in supercritical carbon dioxide with/without co-solvent: Experimental data and modeling (empirical and thermodynamic models)

Improving and measuring the solubility of favipiravir and montelukast in SC-CO2 with ethanol projecting their nanonization

Supercritical carbon dioxide (SC-CO2)-based approaches have become more popular in recent years as alternative methods for creating micro- or nanosized medicines. Particularly, high drug solubility is required in those techniques using SC-CO2 as a solvent. During the most recent pandemic years, favipiravir and montelukast were two of the most often prescribed medications for the treatment of COVID-19. In this study, ethanol at 1 and 3 mol% was utilized as a cosolvent to increase the solubility of both medicines in SC-CO2 by a static approach using a range of temperatures (308 to 338 K) and pressure (12 to 30 MPa) values. The experimentally determined solubilities of favipiravir and montelukast in SC-CO2 + 3 mol% ethanol showed solubility values up to 33.3 and 24.5 times higher than that obtained for these drugs with only SC-CO2. The highest values were achieved in the pressure of 12 MPa and temperature of 338 K. Last but not least, six density-based semi-empirical models with various adjustable parameters were used to perform the modeling of the solubility of favipiravir and montelukast.

Comparison of Four Density-Based Semi-Empirical Models for the Solubility of Azo Disperse Dyes in Supercritical Carbon Dioxide

Compared to traditional water dyeing, supercritical CO2 fluid waterless dyeing is more advanced concerning zero pollution, energy saving and emission reduction. The measurement of the solubility of disperse dyes in supercritical CO2 provides convenience and technological basis for the popularization and development of this technology. In the current work, the solubility of 2-[4-(2-Cyanoethylethylamino)phenyl]diazenyl-5-nitrobenzonitrile (C.I. Dispersed Red 73), 2,2′-[[4-[(4-Nitrophenyl)azo]phenyl]imino] bis-ethano (C.I. Dispersed Red 19) and 3,3′-[[4-[(4-nitrophenyl)azo]phenyl]imino] bispropiononitrile (C.I. Dispersed Orange S-RL) in supercritical CO2 was determined by flow-type supercritical fluid equipment at pressures ranging from 14 to 26 MPa and temperatures ranging from 343.15 to 403.15 K, and the solubility ranges were 1.96–19.78 × 10−6, 1.51–2.63 × 10−6 and 1.49–2.49 × 10−6 mol/mol, respectively. The increase in pressure P and temperature T has obvious effect on the increase in dye solubility. Dyes with high polarity have low solubility. Four density-based, semi-empirical models—the Chrastil, Mendez-Santiago–Teja, Kumar–Johnston and Bartle models—were employed to correlate and predict the solubility data obtained. The results showed that the relationship between the calculated and experimental values correlated best with the Kumar–Johnston model.

A numerical approach to determine the optimal condition of the gas anti-solvent supercritical process for nanoparticles production

Supercritical gas antisolvent (GAS) process is an efficient method for nanoparticles production, in which accurate selection of operational condition is essential. Thermodynamic models can be applied for evaluation the phase equilibrium behavior and determination the required precipitation pressure of GAS process. In this research, thermodynamic behavior of (CO₂—dimethyl sulfoxide (DMSO)) binary system and both of (CO₂–DMSO-anthraquinone Violet 3RN (AV3RN)) and (CO₂–DMSO-solvent Yellow 33 (SY33)) ternary systems in the GAS process were studied at different temperatures (308, 318, 328 and 338) K and pressures (1.0–14.0) MPa, using Peng–Robinson equation of state (PR-EoS). The minimum precipitation pressure of AV3RN and SY33 at 308, 318, 328 and 338 K were 7.80, 8.57, 9.78 and 11 MPa and 8, 8.63, 9.5 and 10.77 MPa, respectively. Also, the mole fraction of substances in liquid phase of ternary systems were determined by PR-EoS, at 328 K versus pressure. The accuracy of the obtained results were investigated using the experimental data reported in the literatures.