Abstract:Curcumin is a natural phenolic pigment extracted from turmeric and has a good pharmacological activity in anti-inflammatory, antioxidant, hypolipidemic, and antitumor. It has been frequently used in drug-loaded microspheres recently. However, the reports on its solubility in supercritical fluids have not been seen yet. In the present study, solubility of curcumin in the supercritical carbon dioxide (ScCO 2 ) was determined using the dynamic equilibrium method. The experimental measurements were performed at te… Show more
“…Supercritical drying was conducted for 6 h at 120 bar and 40 • C, the conditions optimized for polysaccharides drying [21]. Since curcumin is poorly soluble in supercritical carbon dioxide (2 × 10 −8 mole fraction for given drying conditions) [22], there was no risk of washing it out during drying.…”
The following study describes the preparation of pectin aerogels and pectin aerogels coated with an external layer of chitosan. For the preparation of chitosan-coated pectin aerogels, a modified coating procedure was employed. Since pectin as well as pectin aerogels are highly water soluble, a function of chitosan coating is to slow down the dissolution of pectin and consequently the release of the active substances. Textural properties, surface morphologies, thermal properties, and functional groups of prepared aerogels were determined. Results indicated that the coating procedure affected the textural properties of pectin aerogels, resulting in smaller specific surface areas of 276 m2/g, compared to 441 m2/g. However, chitosan-coated pectin aerogels still retained favorable properties for carriers of active substances. The case study for prepared aerogels was conducted with curcumin. Prior to in-vitro release studies, swelling studies were performed. Curcumin’s dissolution from both aerogels showed to be successful. Pectin aerogels released curcumin in 3 h showing a burst release profile. Chitosan-coated pectin aerogels prolonged curcumin release up to 24 h, thus showing a controlled release profile.
“…Supercritical drying was conducted for 6 h at 120 bar and 40 • C, the conditions optimized for polysaccharides drying [21]. Since curcumin is poorly soluble in supercritical carbon dioxide (2 × 10 −8 mole fraction for given drying conditions) [22], there was no risk of washing it out during drying.…”
The following study describes the preparation of pectin aerogels and pectin aerogels coated with an external layer of chitosan. For the preparation of chitosan-coated pectin aerogels, a modified coating procedure was employed. Since pectin as well as pectin aerogels are highly water soluble, a function of chitosan coating is to slow down the dissolution of pectin and consequently the release of the active substances. Textural properties, surface morphologies, thermal properties, and functional groups of prepared aerogels were determined. Results indicated that the coating procedure affected the textural properties of pectin aerogels, resulting in smaller specific surface areas of 276 m2/g, compared to 441 m2/g. However, chitosan-coated pectin aerogels still retained favorable properties for carriers of active substances. The case study for prepared aerogels was conducted with curcumin. Prior to in-vitro release studies, swelling studies were performed. Curcumin’s dissolution from both aerogels showed to be successful. Pectin aerogels released curcumin in 3 h showing a burst release profile. Chitosan-coated pectin aerogels prolonged curcumin release up to 24 h, thus showing a controlled release profile.
“…At the same time, a quick precipitation occurred in the nanopores, as a result, formation of well-ordered curcumin crystals was prevented. At 10 MPa and 40 °C, solubility of curcumin in SC-CO 2 is very low (~4 * 10 −7 g/L) 33 ; therefore, while ethanol is dissolved in the SC-CO 2 and carried outside, curcumin stays in the NSA. This novel nanomanufacturing method eliminated the additional SC-CO 2 impregnation step after SC-CO 2 drying which was the case in our previous phytosterol nanoparticle formation study 27 .Figure 1Illustration of the simultaneous NSA and low-crystallinity curcumin nanoparticle formation.…”
Health-promoting effects of curcumin are well-known; however, curcumin has a very low bioavailability due to its crystalline structure. The main objective of this study was to develop a novel green nanoparticle formation method to generate low-crystallinity curcumin nanoparticles to enhance the bioavailability of curcumin. Nanoporous starch aerogels (NSAs) (surface area of 60 m2/g, pore size of 20 nm, density of 0.11 g/cm3, and porosity of 93%) were employed as a mold to produce curcumin nanoparticles with the help of supercritical carbon dioxide (SC-CO2). The average particle size of the curcumin nanoparticles was 66 nm. Impregnation into NSAs decreased the crystallinity of curcumin and did not create any chemical bonding between curcumin nanoparticles and the NSA matrix. The highest impregnation capacity was 224.2 mg curcumin/g NSA. Curcumin nanoparticles significantly enhanced the bioaccessibility of curcumin by 173-fold when compared to the original curcumin. The concentration of curcumin in the bioaccessible fraction was improved from 0.003 to 0.125 mg/mL by impregnation of curcumin into NSAs (42-fold). This is a novel approach to produce food grade curcumin nanoparticles with reduced crystallinity and maximize the utilization of curcumin due to increased bioaccessibility.
“…80 They could represent an interesting alternative to some synthetic reactive disperse dyes because of the biodegradation capacity of curcumin. Since curcumin exhibits low solubility in supercritical carbon dioxide, 81 it was proposed to modify the molecular structure of the dye by grafting different alkyl groups (ethyl, butyl, hexyl, octyl) to increase the hydrophobicity of the solute. Butyl curcumin resulted in the highest solubility enhancement and consequently a better dyeing performance, which was conducted at 110°C and 26 MPa.…”
Supercritical fluid dyeing is a promising technology that was first proposed in the 1980s to overcome the high energy demand and water consumption of conventional textile coloration. This review covers its advances from 2014 to the present, from the successful industrial implementation of supercritical fluid dyeing of polyethylene terephthalate to the most recent results obtained for the dyeing of other synthetic and natural textiles. Specific attention is also dedicated to the most innovative applications of supercritical fluid dyeing such as the functionalisation of textile and non-textile substrates, which may give rise to the development of other sustainable processes or novel advanced materials in the near future.
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