PMC:7538403 / 5411-6606 JSONTXT

{"project":"2_test","denotations":[{"id":"33025335-25823648-27169","span":{"begin":272,"end":273},"obj":"25823648"}],"text":"All solutions were freshly prepared and filtered through 0.2-μm membrane filters (polytetrafluoroethylene for organic solutions or polyethersulfone for aqueous solutions). Double emulsions were prepared using focused ultrasound according to a previously described method (9). In brief, PLGA was dissolved to 12 mg/mL in 70 mL ethyl acetate and added to 14 mL of an aqueous solution of 6 mg/mL ovalbumin. The mixture was circulated through the flow cell of a commercial focused ultrasound transducer (Covaris S2x, Covaris Inc.; Woburn, MA, USA) using a peristaltic pump at 50 mL/min. The mixture was homogenized for 5 min at intensity 10, duty factor 50%, 300 cycles per burst. An aqueous solution, 140 mL of 20 mg/mL PVA or P‐407, was added, and the mixture was again emulsified by focused ultrasound for 45 min (same settings). An aliquot of this emulsion was precipitated by solvent displacement (10‐fold dilution with purified water). The particle size distribution of the obtained nanoparticle suspension was measured by dynamic light scattering as described below. The results served as a control for in‐use emulsion stability and as a target for nanoparticles precipitated by spray drying."}