BP 2025 (Ph. Eur. 11.6 update)
Action and use
Non-ionic surfactant.
Ph Eur
DEFINITION
Macrogol 20 glycerol monostearate is obtained by ethoxylation with ethylene oxide of different types of glycerol stearates, mainly Glycerol monostearate 40-55 (0495). The number of moles of ethylene oxide reacted per mole of glycerol stearate is 20 (nominal value).
CHARACTERS
Appearance
Pale yellow, oily liquid or gel.
Solubility
Soluble in water at 40 °C and above and in ethanol (96 per cent), practically insoluble in light liquid paraffin and in fatty oils.
Relative density
About 1.07.
IDENTIFICATION
- Hydroxyl value (see Tests).
- Saponification value (see Tests).
- Composition of fatty acids (see Tests).
- Place 1 g in a test tube and add 0.1 mL of sulfuric acid R. Heat the tube until white fumes appear. The fumes turn filter paper impregnated with alkaline potassium tetraiodomercurate solution R black.
TESTS
Acid value (2.5.1)
Maximum 2.0, determined on 5.0 g.
Hydroxyl value (2.5.3, Method A)
65 to 85, determined on 0.350 g.
Iodine value (2.5.4, Method A)
Maximum 2.0.
Peroxide value (2.5.5, Method A)
Maximum 6.0.
Saponification value (2.5.6)
40 to 60.
Composition of fatty acids
Gas chromatography (2.4.22, Method C).
Composition of the fatty-acid fraction of the substance:
| Type of macrogol 20 glycerol monostearate | Type of glycerol stearate used | Composition of fatty acids |
| Type I | Type I
(obtained using stearic acid 50) |
Stearic acid: 40.0 per cent to 60.0 per cent, Sum of the contents of palmitic and stearic acids: minimum 90.0 per cent. |
| Type II | Type II
(obtained using stearic acid 70) |
Stearic acid: 60.0 per cent to 80.0 per cent, Sum of the contents of palmitic and stearic acids: minimum 90.0 per cent. |
| Type III | Type III
(obtained using stearic acid 95) |
Stearic acid: 90.0 per cent to 99.0 per cent, Sum of the contents of palmitic and stearic acids: minimum 96.0 per cent. |
Ethylene oxide and dioxan (2.4.25, Method A)
Maximum 1 ppm of ethylene oxide and maximum 10 ppm of dioxan.
Water (2.5.12)
Maximum 3.0 per cent, determined on 1.00 g.
Total ash (2.4.16)
Maximum 0.2 per cent.
STORAGE
Protected from light.
LABELLING
The label states the type of macrogol 20 glycerol monostearate.
Ph Eur
