A critical review on the particle generation and other applications of rapid expansion of supercritical solution

Development of a novel theory of pressure-induced nucleation in supercritical carbon dioxide

“…43 Therefore, the phase separation caused by pressure relief for the supercritical solution can result in the supersaturation of the solute and the precipitation of particles without any CO 2 residual in the target product. 44 The essence of classical nucleation theory (CNT) 45,46 is that the supersaturation of the solute acts as the driving force to form a nucleus for temperature-induced nucleation. Although CNT is successful in the qualitative interpretation of melt and solution nucleation phenomena, 47 the theory cannot accurately predict the nucleation size and nucleation rate in supercritical fluids.…”

“…49,50 Debenedetti et al 51,52 introduced K, a function of temperature and pressure defined from the fugacity coefficient of solutes in dilute solutions, to modify the nucleation driving force in rapid expansion of supercritical solutions (RESS). 44 Subsequently, they analyzed the evolution of homogeneous nucleation rate, work of nucleus formation and the size of the critical nucleus along different expansion paths for the system of phenanthrene-CO 2 using the modified model. However, the initial solute concentration was 1.5 × 10 −2 ≤ y* ≤ 4.5 × 10 −2 in their work, the dilute solution hypothesis was not acceptable in that case, so the modified model cannot accurately predict the nucleation rate and critical nucleation size.…”

“…43 Therefore, the phase separation caused by pressure relief for the supercritical solution can result in the supersaturation of the solute and the precipitation of particles without any CO 2 residual in the target product. 44…”

Formation of pigment-loaded lipid particles using supercritical CO>sub<2>/sub<

“…In the RESS process, equilibrium between solute and supercritical fluid is reached at temperatures well below the melting point of the solute, so the two phases are the solid phase (almost pure solute) and the supercritical phase (in which the solute is partially dissolved). The diluted supercritical phase is then depressurised to precipitate solid particles (KUMAR et al 2021).…”

“…On the other hand, specific reviews on particle formation by supercritical technologies have not paid much attention to solid lipid particles and structured lipid carriers (PADRELA et al, 2018;KUMAR, R. et al 2021). However, supercritical CO2 is a promising alternative for the formation of these particles in the context of high consumer interest in natural products and stricter government regulations on the use of organic solvents like hexane (TEMELLI, 2009), and technological advantages such as the use of low-cost solvent, not using water to mix the carrier material and the bioactive substance, operation at moderate temperatures and inert atmosphere (without oxygen) that prevents the degradation of bioactive substances.…”