Barnstead thermolyne nanopure water purification system

Ivacaftor-loaded PLGA microparticles were prepared using an oil-in-water single emulsion solvent evaporation technique (Supplemental Figure 1) as previously described (Khaled et al. 2010 (link); Naguib et al. 2021 (link)), using different formulation parameters as described in Table 1. Briefly, 5 or 10 mg ivacaftor and 50 mg of PLGA polymer were dissolved in 1.5 mL of DCM (the organic phase). The organic solution was added to 30 mL of aqueous PVA solution (1 or 1.5% w/v) and the mixture was immediately emulsified for 1 min at different homogenizing speeds (6500 or 13500 rpm) at room temperature using an overhead homogenizer (Ultra-turrax T25 basic, Ika Works, Inc., Wilmington, NC). The emulsion was kept stirring at a speed of 300 rpm using a magnetic digital stirrer for 2 h at 25 °C to evaporate the organic solvent. Microparticles were then collected by centrifugation of the suspension at 1000 x g for 5 min (Eppendorf centrifuge 5864 R, Eppendorf North America, Hauppauge, NY), washed three times with 30 mL Nanopure water (Barnstead Thermolyne Nanopure water purification system, Thermo Fisher, Waltham, MA), and freeze-dried overnight till further in vitro studies (Labconco Free zone 4.5L–105 °C, Labconco, Kansas City, MO).