Soybean oil

• BPRefined Soya Oil
• JPSoybean Oil
• Ph. Eur.Soya-bean Oil, Refined
• USP–NFSoybean Oil

Oleum sojae raffinatum; refined soya-bean oil; soja bean oil; soya oil; soyabean oil

Refined fixed oil obtained from the seeds of the soya plant (Glycine max); a mixture of triglycerides of mainly unsaturated fatty acids · [8001-22-7]

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

Oleaginous vehicle

Typical concentrations: — · Dosage forms: Sterile (parenteral/ophthalmic)

Refined soybean oil is the main oil phase of parenteral fat emulsions used in nutrition (typically 10–30% w/v) and of some injectable emulsions of lipophilic drugs such as propofol. It is also used as a solvent and vehicle in oral emulsions, soft gelatin capsules and other lipid-based formulations, in topical creams and bath oils, and as an edible oil in foods.

A clear, pale-yellow, oily liquid, odourless or with a slight characteristic odour and a bland taste. The fatty-acid fraction is made up mainly of linoleic acid (roughly half), oleic acid, palmitic acid and α-linolenic acid, with smaller amounts of stearic acid. It solidifies at well below 0 °C.

Density

about 0.92 g/cm³ at 20 °C

Iodine value

about 120–140, reflecting a high content of polyunsaturated fatty acids

Saponification value

about 185–195

Main fatty acids

linoleic about 48–58%; oleic about 17–30%; palmitic about 9–13%; α-linolenic about 5–11%; stearic about 3–5%

Solubility

practically insoluble in water and ethanol; miscible with chloroform, ether, light petroleum and other fixed oils

Because of its high content of polyunsaturated fatty acids, soybean oil oxidises on exposure to air, light and heat, with an increase in peroxide value and development of rancidity; antioxidants such as tocopherol are often added. Store in a well-filled, airtight, light-resistant container under nitrogen, in a cool place. Fat emulsions should be protected from freezing and stored as specified.

Incompatible with strong oxidising agents. Emulsions containing soybean oil are destabilised by high concentrations of electrolytes, particularly divalent cations such as calcium and magnesium, by low pH and by some drugs, which can cause creaming, oiling out and coalescence.

Obtained by solvent extraction (usually with hexane) or expression of soybean seeds, followed by refining: degumming, neutralisation, bleaching and deodorisation. Parenteral grades are further purified and controlled for peroxides, fatty-acid composition and contaminants.

Refined soybean oil is a common food and is non-toxic and non-irritant when taken orally or applied topically. Intravenous fat emulsions can cause hypersensitivity reactions (including in people allergic to soya or peanut), fat-overload syndrome, hyperlipidaemia and, in long-term use, liver dysfunction; they must be used with care in neonates.

Observe normal precautions for the quantity handled. Spills are slippery; oil-soaked rags may self-heat, so dispose of them safely.

Used widely as an edible oil. Included in the FDA Inactive Ingredient Database (IV injections, oral capsules and topical preparations) and in parenteral and non-parenteral medicines licensed in Europe.

Hydrogenated soybean oil; soybean lecithin; corn oil; cottonseed oil; sesame oil; medium-chain triglycerides.

For parenteral emulsions use a dedicated injectable grade with low peroxide value and controlled phytosterol content, and protect the oil from oxygen throughout processing. Mixed lipid emulsions combining soybean oil with medium-chain triglycerides, olive oil or fish oil are used to reduce the load of ω-6 fatty acids.