Abstract: Compositions in the form of oil-based solutions that form oil-in-water (OIW) microemulsions in the aqueous environment of the GI tract when taken orally via a hard or soft capsule are described. The resulting microemulsions that form from the oil-based solution within the GI tract can rapidly deliver oil-soluble species and alcohol-soluble species (including PEG derivative assisted alcohol-soluble species) deliverables to the bloodstream through the tissues forming the GI tract. The in situ formed microemulsions resulting from consumption of the encapsulated oil-based solutions include oil-phase microemulsion droplets of monolayer surfactant bound particles suspended in the aqueous continuous phase of the GI tract. The oil-based solutions also may in situ form water-core liposomes suspended in the aqueous continuous phase of the GI tract.