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.

Experimental and modeling of solubility of sitagliptin phosphate, in supercritical carbon dioxide: proposing a new association model

The solubility of an anti-hyperglycemic agent drug, (R)-4-oxo-4-[3-(trifluoromethyl)-5,6-dihydro [1,2,4] triazolo[4,3-a] pyrazin-7(8H)-yl]-1-(2,4,5-trifluorophenyl) butan-2-amine (also known as Sitagliptin phosphate) in supercritical carbon dioxide (scCO2) was determined by ananalytical and dynamic technique at different temperatures (308, 318, 328 and 338 K) and pressure (12-30 MPa) values. The measured solubilities were in the range of 3.02 × 10-5 to 5.17 × 10-5, 2.71 × 10-5 to 5.83 × 10-5, 2.39 × 10-5 to 6.51 × 10-5 and 2.07 × 10-5 to 6.98 × 10-5 in mole fraction at (308, 318, 328 and 338) K, respectively. The solubility data were correlated with existing density models and with a new association model.

Solubility measurement of verapamil for the preparation of developed nanomedicines using supercritical fluid

A static method is employed to determine the solubilities of verapamil in supercritical carbon dioxide (SC-CO2) at temperatures between 308 and 338 K and pressures between 12 and 30 MPa. The solubility of verapamil in SC-CO2 expressed as mole fraction are in the range of 3.6 × 10-6 to 7.14 × 10-5. Using four semi-empirical density-based models, the solubility data are correlated: Chrastil, Bartle, Kumar-Johnston (K-J), and Mendez-Santiago and Teja (MST), two equations of state (SRK and PC-SAFT EoS), expanded liquid models (modified Wilson's models), and regular solution model. The obtained results indicated that the regular solution and PC-SAFT models showed the most noteworthy exactness with AARD% of 1.68 and 7.45, respectively. The total heat, vaporization heat, and solvation heat of verapamil are calculated at 39.62, 60.03, and - 20.41 kJ/mol, respectively. Regarding the poor solubility of verapamil in SC-CO2, supercritical anti-solvent methods can be an appropriate choice to produce fine particles of this drug.

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.

Preparation of phthalocyanine green nano pigment using supercritical CO2 gas antisolvent (GAS): experimental and modeling

Phthalocyanine green nano pigment was prepared using supercritical gas antisolvent (GAS) process based on the SC-CO₂ method. Thermodynamic models were developed to study the volume expansion and operating conditions of the GAS process. Peng-Robinson EoS were applied for binary (CO₂ and DMSO) and ternary (CO₂, DMSO, and pigment) systems. A Box-Behnken experimental design was used to optimize the process. Influences of temperature (308, 318 and 328 K), pressure (10, 15 and 20 MPa) and solute concentration (10, 40 and 70 mg/mL) were studied on the particles size and their morphology. The fine particles produced were characterized by SEM, DLS, XRD, FTIR and DSC. Experimental results showed a great reduction in size of pigment particles in comparison to the original particles. The mean particle sizes of nanoparticles were obtained to 27.1 nm after GAS based on SC-CO₂ method.