Food additives Europe numbers: E1503
Functional Category
Emollient; oleaginous vehicle; solvent.
Applications in Pharmaceutical Formulation
Castor oil is widely used in cosmetics, food products, and pharmaceutical formulations. In pharmaceutical formulations, castor oil is most commonly used in topical creams and ointments at concentrations of 5–12.5%. However, it is also used in oral tablet and capsule formulations, ophthalmic emulsions, and as a solvent in intramuscular injections.(1–3) Therapeutically, castor oil has been administered orally for its laxative action, but such use is now obsolete
Description
Castor oil is a clear, almost colorless or pale yellow-colored viscous oil. It has a slight odor and a taste that is initially bland but afterwards slightly acrid.
Stability and Storage Conditions
Castor oil is stable and does not turn rancid unless subjected to excessive heat. On heating at 3008C for several hours, castor oil polymerizes and becomes soluble in mineral oil. When cooled to 08C, it becomes more viscous. Castor oil should be stored at a temperature not exceeding 258C in well-filled airtight containers protected from light.
Incompatibilities
Castor oil is incompatible with strong oxidizing agents.
Safety
Castor oil is used in cosmetics and foods and orally, parenterally, and topically in pharmaceutical formulations. It is generally regarded as a relatively nontoxic and nonirritant material when used as an excipient.(4) Castor oil has been used therapeutically as a laxative and oral administration of large quantities may cause nausea, vomiting, colic, and severe purgation. It should not be given when intestinal obstruction is present. Although widely used in topical preparations, including ophthalmic formulations, castor oil has been associated with some reports of allergic contact dermatitis, mainly to cosmetics such as lipsticks.