Production of stabilized quercetin aqueous suspensions by supercritical fluid extraction of emulsions

Abstract

Quercetin is a flavonoid with highly promising bioactivity against a variety of diseases, due to its strong antioxidant, antiviral and antihistaminic effect, but these applications are limited by the low solubility of quercetin in gastrointestinal fluids and the correspondingly low bioavailability. The objective of this work is to produce encapsulated quercetin particles in sub-micrometric scale, in order to increase their low bioavailability. These particles were produced by extraction of organic solvent from oil in water emulsions by Supercritical Fluid Extraction of Emulsions (SFEE). Due to the rapid extraction of organic solvent by this method, the disperse organic phase becomes rapidly supersaturated, causing the precipitation of quercetin particles in sub-micrometric scale, encapsulated by the surfactant material. Two different biopolymers (Pluronic L64 ® poloxamers and soy bean lecithin) were used as carriers and surfactant materials. In experiments with Pluronic, needle quercetin particles were obtained after SFEE treatment, with particle sizes around 1 µm and poor encapsulation efficiency. In case of soy lecithin, quercetin-loaded multivesicular liposomes were obtained, with a mean particle size around 100 nm and around 70% encapsulation efficiency of quercetin, without presence of segregated quercetin crystals.

Production of encapsulated quercetin particles using supercritical fluid technologies

“…As detailed in previous works, soy-bean lecithin proved to be a suitable material for encapsulating in nanometric scale precipitated quercetin [18]. Moreover, according to surface tension measurements, using a mixture of soy-bean lecithin with Pluronic L64 ® as additional surfactant, a significant reduction in surface tension is observed [27].…”

“…As in a previous work, a batch SFEE equipment [18] was used to extract the organic content of the o/w emulsion under the restrictions of FDA [19], and to produce aqueous suspensions, containing quercetin loaded lecithin nanoparticles. The equipment consists of an extractor and a buffer vessel, which are located in a heated oven, and are separable from each other using two valves.…”

“…To do so, the extraction vessel was isolated from the recirculation circuit, in order to maintain the extraction vessel at a constant pressure and temperature, meanwhile the CO 2 was renewed in the rest of the circuit, thus minimizing the disturbances and losses of emulsion by entrapment in CO 2 during the repeated depressurization processes needed for each CO 2 renewal. According to preliminary experiments, five cycles with a total treatment duration of 575 min proved to be optimum, and allowed decreasing the residual organic content under the restriction of the FDA [19], without significant degradation or agglomeration effect of the encapsulated quercetin particles [18]. Upon termination of the process, the complete system was slowly depressurized using a Milli-Mite ® serie 1300 micrometric valve provide by HOKE, and produced aqueous suspension product was stored at 4-6°C, protected from light.…”

“…Measurements were done twice, and calibration series were done in the range of 0 -1000 mg/L EtAc concentration with R 2 = 0.999. The method of GC analysis was detailed in previous work [18]. Briefly, 4 mL of sample were introduced in a hermetically closed vial with a volume of 10 mL, and vials were tempered before GC injection at 40°C.…”

Eco-friendly Multifunction Petroleum Additives: Preparation, Characterization and Evaluation

“…This data indicates that in the phenolipids (1) and (2), quercetin is encapsulated by SL as presented in Fig. 4 [41] and it is not present as segregated crystals [42].…”