Absorption after oral administration is a requirement for almost all drug products, but is a challenge for drugs with intrinsically low water solubility. Here, the weakly basic, poorly water-soluble drugs (PWSD) itraconazole, cinnarizine and halofantrine were converted into lipophilic ionic liquids to facilitate incorporation into lipid-based formulations and integration into lipid absorption pathways. Ionic liquids were formed via metathesis reactions of the hydrochloride salt of the PWSD with a range of lipophilic acid counterions. The resultant active pharmaceutical ingredient - ionic liquids (API-ILs) were liquids or low melting point solids and either completely miscible or highly soluble in lipid based, self-emulsifying drug delivery systems (SEDDS) comprising mixtures of long or medium chain glycerides, Kolliphor-EL and ethanol. They also readily incorporated into the colloids formed in intestinal fluids during lipid digestion. Itraconazole docusate or cinnarizine decylsulfate ionic liquids were subsequently dissolved in long chain lipid SEDDS at high concentration, administered to rats and in vivo exposure assessed. Data were compared to control formulations based on the same SEDDS formulations containing the same concentrations of drug as the free base, but in this case as a suspension (since the solubility of the free base in the SEDDS was much lower than the API-ILs). For itraconazole, comparison was also made to a physical mixture of itraconazole free base and docusate sodium in the same SEDDS formulation. For both drugs plasma exposure was significantly higher for the ionic liquid containing formulations (2-fold for cinnarizine and 20-fold for itraconazole), when compared to the suspension formulations (or the physical mixture in the case of itraconazole) at the same dose. The liquid SEDDS formulations, made possible by the use of the API-ILs, also provide advantages in dose uniformity, capsule filling and stability compared to similar suspension formulations. The data suggest that the formation of lipophilic ionic liquids provides a means of increasing dissolved-drug loading in lipid based formulations and thereby promoting the exposure of poorly water soluble drugs after oral administration.