(Ph. Eur. monograph 1001)
Action and use
Plasma substitute.
Preparation
Dextran 70 Infusion
DEFINITION
Mixture of polysaccharides, principally of the α-1,6-glucan type.
Average relative molecular mass About 70 000.
PRODUCTION
It is obtained by hydrolysis and fractionation of dextrans produced by fermentation of sucrose using Leuconostoc mesenteroides strain NRRL B-512 = CIP 78.59 or substrains thereof (for example L. mesenteroides B-512F = NCTC 10817).
It is prepared in conditions designed to minimise the risk of microbial contamination.
CHARACTERS
Appearance
White or almost white powder.
Solubility
Very soluble in water, very slightly soluble in ethanol (96 per cent).
IDENTIFICATION
A. Specific optical rotation (2.2.7): + 195 to + 201 (dried substance).
Dissolve 1.0 g in water R, heating on a water-bath, and dilute to 50.0 mL with the same solvent.
B. Infrared absorption spectrophotometry (2.2.24).
Comparison: dextran CRS.
C. Molecular-mass distribution (see Tests).
TESTS
Solution S
Dissolve 5.0 g in distilled water R, heating on a water-bath, and dilute to 50 mL with the same solvent.
Appearance of solution
Solution S is clear (2.2.1) and colourless (2.2.2, Method II).
Acidity or alkalinity
To 10 mL of solution S add 0.1 mL of phenolphthalein solution R. The solution remains colourless. Add 0.2 mL of 0.01 M sodium hydroxide. The solution is red. Add 0.4 mL of 0.01 M hydrochloric acid. The solution is colourless. Add 0.1 mL of methyl red solution R. The solution is red or orange.
Nitrogen-containing substances
Maximum 110 ppm of N.
Carry out the determination of nitrogen by sulfuric acid digestion (2.5.9), using 0.200 g and heating for 2 h. Collect the distillate in a mixture of 0.5 mL of bromocresol green solution R, 0.5 mL of methyl red solution R and 20 mL of water R.
Titrate with 0.01 M hydrochloric acid. Not more than 0.15 mL of 0.01 M hydrochloric acid is required to change the colour of the indicator.
Residual solvents
Gas chromatography (2.2.28).
Internal standard propanol R.
Test solution: Dissolve 5 g of the substance to be examined in 100 mL of water R and distil. Collect the first 45 mL of the distillate, add 1 mL of a 25 g/L solution of propanol R and dilute to 50 mL with water R.
Reference solution: Mix 0.5 mL of a 25 g/L solution of anhydrous ethanol R, 0.5 mL of a 25 g/L solution of propanol R and
0.5 mL of a 2.5 g/L solution of methanol R and dilute to 25.0 mL with water R.
Column:
— material: stainless steel;
— size: l = 1.8 m, Ø = 2 mm;
— stationary phase: ethylvinylbenzene-divinylbenzene copolymer R (125-150 μm).
Carrier gas nitrogen for chromatography R.
Flow rate: 25 mL/min.
Temperature:
— column: 190 °C;
— injection port: 240 °C;
— detector: 210 °C.
Detection: Flame ionisation.
Injection: The chosen volume of each solution.
Limits:
— ethanol: not more than the area of the corresponding peak in the chromatogram obtained with the reference solution (0.5 per cent);
— methanol: not more than the area of the corresponding peak in the chromatogram obtained with the reference solution (0.05 per cent);
— sum of solvents other than ethanol, methanol and propanol: not more than the area of the peak due to the internal standard (0.5 per cent, calculated as propanol).
Molecular-mass distribution (2.2.39)
The average molecular mass (Mw) is 64 000 to 76 000. The average molecular mass of the 10 per cent high fraction is not greater than 185 000. The average molecular mass of the 10 per cent low fraction is not less than 15 000.
Loss on drying (2.2.32)
Maximum 7.0 per cent, determined on 0.200 g by heating in an oven at 105 ± 2 °C for 5 h.
Sulfated ash (2.4.14)
Maximum 0.3 per cent, determined on 0.50 g.
Bacterial endotoxins (2.6.14)
Less than 16 IU/g.
Microbial contamination
TAMC: acceptance criterion 10 CFU/g (2.6.12).
