IMQ (>99%) was obtained from Hubei Vanz Pharm co. Ltd (Wuhan, China). Tween® 20 and Tween® 80 were purchased from Sigma-Aldrich (NSW, Australia). Precirol® ATO 5 (Glyceryl distearate), Compritol® 888 ATO (Glyceryl dibehenate), Gelucire® 48/16 (Polyoxyl-32 stearate), Gelucire® 50/13 (Stearoyl polyoxyl-32 glycerides), and Apifil® were kindly gifted by Gattefossé (St Priest, France). Peceol™, Captex® 300 Low C6, Captex® 500, Capmul® PG-8, and Capmul® PG-12 were kindly gifted by Abitec Corporation (OH, USA). Stearyl alcohol (STA), propylene glycol (PG) and oleic acid (OA) were procured from PCCA (NSW, Australia). Almond oil and sesame oil were purchased from Medisca (NSW, Australia). Isopropyl myristate and Miglyol® 812 were obtained from Acros organics (New Jersey, USA) and Bova compounding (NSW, Australia), respectively. Benecel™ K4M was received as a gift from Ashland (KY, USA). D100 D-Squame® sampling discs and D500 D-Squame® pressure instrument were purchased from Clinical & Derm (TX, USA).