Selecting Critical Properties of Terpenes and Terpenoids through Group-Contribution Methods and Equations of State

Solubility of gemcitabine (an anticancer drug) in supercritical carbon dioxide green solvent: Experimental measurement and thermodynamic modeling

In order to develop supercritical fluid (SCF) processes for the micro or nanosizing of solid solute components, such as pharmaceuticals, it is essential to assess their solubility in solvents including supercritical carbon dioxide (SC-CO2). This crucial step is fundamental for choosing and evaluating the processes in SCF technology. A statistical method was developed and used to determine the solubility of gemcitabine in SC-CO2. The solubility measurements at various pressures and temperatures were conducted using UV-vis analysis. Two model types were used to correlate the data: semi-empirical (with 3-6 parameters) and equation of state (EoS) models. The solubility of gemcitabine in SC-CO2 using a static method at temperatures of 308-338 K and pressures of 120-270 bar were measured and modeled for the first time. Solubility of gemcitabine ranged from 0.1274 × 10- 5 to 1.8128 × 10- 5 in mole fraction and 0.00295 to 0.08489 kg/L. The PR EoS model performed best at 308 K with an AARD of 12.58%, and SRK excelled at 318-338 K with AARDs between 12.93 and 15.68%. Application of the Joback method (AARD 12.04-27.13%) and COSMO-RS method (AARD 18.68-31.28%) in EoS models also were compared. The Bian et al. model showed the best fit among density-based models with an AARD of 16.62%.

Vapor pressure measurements on linalool using a rapid and inexpensive method suitable for cannabis-associated terpenes†

Vapor pressure (psat) data are needed to assess the potential use of terpenes as breath markers of recent cannabis use. Herein, a recently introduced gas-saturation method for psat measurements, known as dynamic vapor microextraction (DVME), was used to measure psat for the terpene (±)-3,7-dimethylocta-1,6-dien-3-ol, commonly known as linalool. The DVME apparatus utilizes inexpensive and commercially available components, a low internal volume, and helium carrier gas to minimize nonideal mixture behavior. In the temperature range from 314 K to 354 K, DVME-based measurements of the psat of linalool ranged from 81 Pa to 1250 Pa. With a measurement period of 30 min, the combined standard uncertainty of these measurements ranged from 0.0358·psat to 0.0584·psat, depending on temperature. The DVME-based measurements agree with a Wagner correlation of available literature data. We demonstrate that DVME produces accurate results for values of psat that are 200 times higher than in the DVME validation study with n-eicosane (C20H42). The oxidative stability of linalool was improved by the addition of 0.2 mass % of the antioxidant tert-butylhydroquinone.