Soybean oil

Oil droplets are made from soybean oil (Sigma-Aldrich, St. Louis, MO, USA). Briefly, soybean oil was dispersed and emulsified by hand in an aqueous continuous phase containing 15% w/w of Poloxamer 188 block polymer surfactant (CRODA, East Yorkshire, UK) and 1% w/w sodium alginate (Sigma-Aldrich, St. Louis, MO, USA) at a final oil fraction equal to 75%. The rough emulsion was sheared in a Couette cell apparatus at a controlled shear rate of 110 rpm as described by Mason et al.39 (link). For storage and handling purposes the emulsion are diluted to an oil fraction of 60% w/w with 1% w/w of poloxamer 188 in the continuous phase and stored at 12 °C in a Peltier-cooled cabinet.
To stain droplets with Nile Red (Sigma-Aldrich, St. Louis, MO, USA), a red lipophilic dye, the droplets suspension is washed and resuspended in cell growth complete media containing 10 μM of Nile Red. Size distribution of the emulsion droplets was measured by brightfield microscopy and image analysis.

Pioglitazone HCl (PGZ) (purity > 99.5%) was obtained by Riyadh Pharma manufacturer (Riyadh, Saudi Arabia). Capryol^TM 90, Transcutol^TM HP, Labrafil^®M1944CS and Labrasol^® were purchased from Gattefossé (Lyon, France). Capmul MCM was obtained by Abitec (Columbus, OH, USA). Olive oil and Soybean oil were gifted from Croda (East Yorkashire, UK). Tween^® 80 and Oleic acid were acquired from Sigma–Aldrich (St. Louis, MO, USA). Propylene glycol (PG) was obtained from Winlab (Gemini-house, UK). Cremophor^® EL and Cremophor^® RH 40 were supplied from BASF (Ludwigshafen, Germany). Pure gelatin capsules (size 000) were supplied by the Center of Applied Research and Advanced Studies, Faculty of Pharmacy, Cairo University (CARAS). Silica powders, Aerosil 200^®, Syloid^® 244 FP (SYL), Neusilin^® grades US2 and UFL2 were donated from Fuji Chemical Industries (Osaka, Japan). Prosolv^® ODT G2, mannitol, fructose and crospovidone were gifted by GRS pharma (Rosenberg, Germany). All other chemicals were of analytical grade.

NE was produced by emulsifying cetylpyridinium chloride (CPC) and Tween 80 at a 1:6 (w/w) ratio, with ethanol (200 proof), super refined soybean oil (Croda) and molecular grade water using a high-speed homogenizer as previously described^{18 (link)}. The emulsion was homogenized to a uniform particle size (d=450-550 nm) and charge (zeta potential=50-55mV). The sequence and synthesis of IVT DI RNA has previously been described in detail^{15 (link), 24 (link)}. Briefly, SeV DI RNA was amplified using a 5’ primer with the T7 promoter and a 3’ primer with the hepatitis delta virus genomic ribozyme site followed by the T7 terminator and cloned into a pUC19 plasmid. IVT DI was in vitro transcribed using a HiScribe T7 High Yield RNA synthesis kit (New England Biolabs) followed by DNAse I clean-up with a TURBO DNA-free kit (Thermo-Fisher). IVT DI was then purified with an RNeasy purification kit (Qiagen), and the absence of endotoxin was verified by a limulus amoebocyte lysate assay (ThermoFisher). Recombinant SARS-CoV-2 receptor binding domain (RBD) (aa319-545) derived from the WT (Wuhan-Hu-1) SARS-CoV-2 isolate with a C-terminal His tag was produced in ExpiCHO cells and purified by the University of Michigan Center for Structural Biology as previously described^{48 (link)}.