Castor oil

• BPVirgin Castor Oil
• JPCastor Oil
• Ph. Eur.Castor Oil, Virgin
• USP–NFCastor Oil

Oleum ricini; palma Christi oil; ricini oleum virginale; ricinus oil; tangantangan oil

Castor oil (triglyceride of fatty acids, mainly ricinoleic acid) · [8001-79-4]

Polymer, mixture or material of variable composition — no single molecular formula applies.

Oleaginous vehicle, Plasticiser

Typical concentrations: — · Dosage forms: Semi-solid, Liquid, Sterile (parenteral/ophthalmic)

Used as an emollient and oily base in topical creams, ointments and lotions, as a solvent and vehicle for some intramuscular injections and oily solutions, as the oil phase of some ophthalmic emulsions, and as a plasticiser for film coatings. It is also widely used in cosmetics such as lipsticks, and orally as a stimulant laxative.

A clear, almost colourless or pale-yellow, viscous oil with a slight odour and a taste that is bland at first and then slightly acrid.

Ricinoleic acid content

85–92% of the fatty acids (Ph. Eur.)

Relative density

≈ 0.96

Viscosity

high for a fixed oil; of the order of 1000 mPa·s at 20 °C

Hydroxyl value

≥ 150

Iodine value

82–90

Solubility

miscible with ethanol, glacial acetic acid, chloroform and ether; slightly soluble in light petroleum; practically insoluble in water

Less prone to rancidity than most fixed oils unless overheated. Store in well-filled, airtight containers protected from light. It can be sterilised by dry heat.

Incompatible with strong oxidising agents.

Obtained by cold expression of the seeds of Ricinus communis, followed by clarification; refined grades are further treated to remove free fatty acids and colour. The toxic protein ricin remains in the seed cake and is not present in the oil.

Generally regarded as non-toxic and non-irritant when used as an excipient in topical and parenteral products. Oral doses of several millilitres or more have a strong purgative effect, and it should be avoided in pregnancy at laxative doses. It should not be confused with the polyoxyl castor oil surfactants, which are associated with hypersensitivity reactions.

Observe normal precautions for the quantity handled. Spills are slippery.

Included in the FDA Inactive Ingredient Database (including intramuscular injections and ophthalmic, oral and topical preparations) and in parenteral and non-parenteral medicines licensed in Europe.

Castor oil, hydrogenated; polyoxyl 35 castor oil; polyoxyl 40 hydrogenated castor oil.

The hydroxyl group of ricinoleic acid makes castor oil unusually viscous and polar for a vegetable oil and gives it its miscibility with ethanol, which other fixed oils lack.