Viscosity Measurement of CO2-Solvent Mixtures for the Study of the Morphology and Size of Crystalline Particles Obtained Using Supercritical Antisolvent Precipitation

The viscosity values of CO2-dimethylphormamide, chloroform, methanol, isopropanol, ethyl acetate, acetone, and dimethyl sulfoxide mixtures were measured at a pressure of 150 bar and a temperature of 313 K. The correlation of the mean size of levofloxacin hydrochloride and malonic acid particles precipitated using the SAS method with the viscosity of the used CO2-solvent mixtures is shown. The high viscosity of the mixtures leads to slower mixing of the solution and the antisolvent. Therefore, crystallization occurs at large fractions of the solvent, and as a consequence at a lower supersaturation. This causes the formation of larger particles when using more viscous solvents in SAS.

Experimental solubility of aripiprazole in supercritical carbon dioxide and modeling

The solubility of compounds in supercritical carbon dioxide (SC-[Formula: see text]) has found crucial significance in the fabrication of micro/nano-scaled drugs. In this research, the solubility of Aripiprazole was measured in SC-[Formula: see text] at various temperatures (308-338 K) and pressures (12-30 MPa). Moreover, the experimental solubility results were correlated with several semi-empirical models (Chrastil, Bartle et al., Kumar & Johnston, Menden-Santiago & Teja, Sodeifian et al., and Jouyban et al.) as well as the modified Wilson model. The molar fraction of the drug in SC-[Formula: see text] varied in the range of [Formula: see text] to [Formula: see text]. The solubility highly depended on the operating pressure and temperature. The Chrastil (0.994), Jouyban et al. (0.993) and Sodeifian et al. (0.992) models showed the highest consistency with the obtained values. Furthermore, self-consistency tests were performed on the solubility of Aripiprazole in SC-[Formula: see text]. The approximate total enthalpy ([Formula: see text]), vaporization enthalpy ([Formula: see text]), and solubility enthalpy ([Formula: see text]) were also calculated.

Solid-State and Particle Size Control of Pharmaceutical Cocrystals using Atomization-Based Techniques

Poor bioavailability and aqueous solubility represent a major constraint during the development of new API molecules and can influence the impact of new medicines or halt their approval to the market. Cocrystals offer a novel and competitive advantage over other conventional methods with respect towards the substantial improvement in solubility profiles relative to the single-API crystals. Furthermore, the production of such cocrystals through atomization-based methods allow for greater control, with respect to particle size reduction, to further increase the solubility of the API. Such atomization-based methods include supercritical fluid methods, conventional spray drying and electrohydrodynamic atomization/electrospraying. The influence of process parameters such as solution flow rates, pressure and solution concentration, in controlling the solid-state and final particle size are discussed in this review with respect to atomization-based methods. For the last decade, literature has been attempting to catch-up with new regulatory rulings regarding the classification of cocrystals, due in part to data sparsity. In recent years, there has been an increase in cocrystal publications, specifically employing atomization-based methods. This review considers the benefits to employing atomization-based methods for the generation of pharmaceutical cocrystals, examines the most recent regulatory changes regarding cocrystals and provides an outlook towards the future of this field.