Edition: BP 2025 (Ph. Eur. 11.6 update)
(Ph. Eur. monograph 1618)
Action and use
Non-ionic surfactant.
Ph Eur
DEFINITION
A mixture of monoesters and diesters of mainly oleic (cis-9-octadecenoic) acid and macrogols. It may be obtained by ethoxylation of Oleic acid (0799) or by esterification of macrogols with oleic acid of animal or vegetable origin. It may contain free macrogols. The average polymer length is equivalent to 5-6 or 10 moles of ethylene oxide per mole (nominal value). A suitable antioxidant may be added.
CHARACTERS
Appearance
Slightly yellowish, viscous liquid.
Solubility
Dispersible in water, soluble in ethanol (96 per cent) and in 2-propanol, dispersible in oils, miscible with fatty oils and with waxes.
Refractive index
About 1.466.
IDENTIFICATION
First identification: A, C.
Second identification: A, B.
A. Saponification value (see Tests).
B. Thin-layer chromatography (2.2.27).
Test solution To 20 mg add 10 mL of methylene chloride R and mix.
Plate TLC silica gel F254 plate R.
Mobile phase 25 per cent V/V solution of concentrated ammonia R, 2-propanol R (20:80 V/V).
Application 10 μL.
Development Over a path of 15 cm.
Drying In air.
Detection Spray with potassium iodobismuthate solution R4; examine the plate about 10 min later.
Results The chromatogram obtained shows 3 principal spots, corresponding, in order of increasing RF value, to free macrogol, macrogol mono-oleate and macrogol dioleate.
C. Composition of fatty acids (see Tests).
TESTS
Alkalinity
Dissolve 2.0 g in ethanol (96 per cent) R and dilute to 20 mL with the same solvent. To 2 mL of this solution add 0.05 mL of phenol red solution R. The solution is not red.
Acid value (2.5.1)
Maximum 2.0.
Hydroxyl value (2.5.3, Method A)
See Table 1618.-1.
Iodine value (2.5.4, Method A)
See Table 1618.-1.
Peroxide value (2.5.5, Method A)
Maximum 12.0.
Saponification value (2.5.6)
See Table 1618.-1.
Table 1618.-1
| 5-6 moles of ethylene oxide | 10 moles of ethylene oxide | |
| Hydroxyl value | 50 – 70 | 65 – 90 |
| Iodine value | 50 – 60 | 27 – 34 |
| Saponification value | 105 – 120 | 68 – 85 |
Composition of fatty acids
Gas chromatography (2.4.22, Method A).
Composition of the fatty-acid fraction of the substance:
— myristic acid: maximum 5.0 per cent;
— stearic acid: maximum 6.0 per cent;
— palmitic acid: maximum 16.0 per cent;
— palmitoleic acid: maximum 8.0 per cent;
— oleic acid: 65.0 per cent to 88.0 per cent;
— linoleic acid: maximum 18.0 per cent;
— linolenic acid: maximum 4.0 per cent;
— fatty acids with a chain length greater than C18: maximum 4.0 per cent.
Residual ethylene oxide and dioxan (2.4.25)
Maximum 1 ppm of residual ethylene oxide and 10 ppm of residual dioxan.
Water (2.5.12)
Maximum 2.0 per cent, determined on 1.00 g using anhydrous methanol R as the solvent.
Total ash (2.4.16)
Maximum 0.3 per cent, determined on 1.0 g.
STORAGE
In an airtight container.
LABELLING
The label states the number of moles of ethylene oxide per mole (nominal value).
Ph Eur
