Ethoxylated hydrogenated castor oil is a combination of synthetic polyethylene glycol (PEG) with natural castor oil. Ethoxylated hydrogenated castor oil can be used to emulsify and solubilize oil-in-water (o/w) emulsions.

Nearly 20% of Ethoxylated hydrogenated castor oil was used to emulsify the glyceryl monooleate (GMO) as an oil to the aqueous phase. In Webster mice, 5000 mg/kg blank nanoemulsion is given orally to mice once a day for 14 days, this nanoemulsion does not produce hazardous effects, and it has no effect on food intake[1]. 20% Ethoxylated hydrogenated castor oil (10 μl) is applied to the left ear of the mouse, and the right ear served as a control. The mice are observed for development of erthyma for 6 days, no signs of irritation are observed in the mice[2]. Ethoxylated hydrogenated castor oil (injection via the tail vein; 300, 900, and 2700 mg/kg; 4 weeks) is administared for short-term toxicity. At doses of 300 and 900 mg/kg PEG-40 Hydrogenated Castor Oi exhibits no systemic toxicity. However, at a dose of 2700 mg/kg, slight ataxia is observed and body weight is reduced significantly in the males and slightly in the females[2].