Castor oil polyoxyethylene ether is a yellow viscous liquid that is resistant to hard water, acid, alkali and inorganic salts. It is used to emulsify and dissolve oil and other water-insoluble substances. It is a non-ionic solubilizer. It is used as a solubilizer and emulsifier for water-insoluble drugs or other fat-soluble drugs in semi-solid and liquid preparations.