Production of encapsulated quercetin particles in sub-micrometric scale

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Figure 1: Schematic diagram of batch Supercritical Extraction of Emulsions (SFEE) equipment

Quercetin is a bioflavonoid with a strong antioxidant-, antiviral-, antibacterial-, antihistaminic-and anti-inflammatory effect. Due to these properties, quercetin is a highly promising material against a wide variety of diseases, including cancer. A major limitation for the clinical application of quercetin is its low bioavailability that makes it necessary to administe in high doses (50 mg/kg). One way to increase the bioavailability of quercetin is to produce encapsulated quercetin particles in nanometric scale, using Supercritical Fluid Extraction of Emulsions (SFEE) technology.

By SFEE process (Figure 1), a previously created oil-in-water emulsion (o/w) (Figure 2 left) is contacted with supercritical carbon dioxide (scCO2) in order to extract the organic part from the emulsion, causing the supersaturation of quercetin solution. Due to the rapid supersaturation of the solution, fast precipitation of quercetin will take place in sub-micrometric scale, encapsulated by the surfactant material. Our aim is to optimize the preparation methods (quantity of quercetin, surfactant material and organic solvent) of the initially prepared o/w emulsion, and the process parameters of SFEE as a batch process: numbers and duration of cycles, pressure and temperature. According to the process, it is crucial to increase the amount of quercetin encapsulated by the surfactant material in the aqueous suspension (Figure 2 right), and to decrease the organic contamination of the final product below the legal restrictions established by the FDA.

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Figure 2: Microscopy picture of initial w/o emulsion (LEFT) and TEM picture of lecithin – quercetin multivesicular system (RIGHT)

 As visible in Figure 3, so far is managed to obtain quercetin encapsulated particles with a mean particle diameter value below 100 nm, with an encapsulation efficiency around 70% and residual organic content under 300 ppm.

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Figure 3: Typical particle size distribution of quercetin – lecithin aqueous suspension

A full report of our results is available at the following link:

György Lévai – Project DoHip (FP7-PEOPLE 2012 ITN 316959)  and project BioQuercetin (VA225U14)

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