(Ph. Eur. monograph 1553)
Action and use
Excipient.
DEFINITION
α-[4-(2,4,4-Trimethylpentan-2-yl)phenyl]-ω-hydroxydeca(oxyethane-1,2-diyl).
Mixture consisting mainly of mono-octylphenyl ethers of macrogols corresponding to the formula C8H17C6H4-[OCH2-CH2]n-OH where the average value of n is 10 (C34H62O11; Mr 646). It may contain free macrogols.
CHARACTERS
Appearance
Clear, colourless or light yellow, viscous liquid.
Solubility
Miscible with water, with ethanol (96 per cent) and with vegetable oils.
IDENTIFICATION
A. Infrared absorption spectrophotometry (2.2.24).
Comparison: octoxinol 10 CRS.
Preparation: Film between sodium chloride R plates.
B. Cloud point (see Tests).
TESTS
Acidity or alkalinity
Boil 1.0 g with 20 mL of carbon dioxide-free water R for 1 min, with constant stirring. Cool and filter. To 10 mL of the filtrate, add 0.05 mL of bromothymol blue solution R1. Not more than 0.5 mL of 0.01 M
hydrochloric acid or 0.01 M sodium hydroxide is required to change the colour of the indicator.
Hydroxyl value (2.5.3, Method A)
85 to 101. Calculate the hydroxyl value using the following expression:
IOH = 28.05 (n2 – n1)/ m
Cloud point
63 °C to 70 °C.
Dissolve 1.0 g in 99 g of water R. Transfer about 30 mL of the solution to a test-tube, heat on a water-bath and stir continuously until the solution becomes cloudy. Remove the test-tube from the water-bath (ensuring
that the temperature does not increase more than 2 °C), and continue to stir. The cloud point is the temperature at which the solution becomes sufficiently clear that the entire thermometer bulb is plainly seen.
Ethylene oxide and dioxan (2.4.25)
Maximum 1 ppm of ethylene oxide and maximum 10 ppm of dioxan.
Water (2.5.12)
Maximum 0.5 per cent, determined on 2.00 g.
Total ash (2.4.16)
Maximum 0.4 per cent, determined on 1.0 g.
STORAGE
In an airtight container.
