» Liquid Glucose is a product obtained by the incomplete hydrolysis of starch. It consists chiefly of dextrose, dextrins, maltose, and water.
Packaging and storage Preserve in tightly closed containers. No storage requirements specified.
Labeling Label it to indicate the natural source of starch. Label it to indicate its nominal dextrose equivalent.
USP Reference standards 11
Identification It meets the requirements of the Assay for reducing sugars (dextrose equivalent).
Acidity To a solution of 5.0 g in 15 mL of water add 5 drops of phenolphthalein TS: not more than 0.60 mL of 0.10 N sodium hydroxide is required to produce a pink color.
Water, Method Ia 921: not more than 21.0%, determined on a 100-mg specimen.
Residue on ignition 281: not more than 0.5%.
Sulfite Dissolve 5 g in 50 mL of water, add 0.2 mL of 0.1 N iodine, then add 0.5 mL of starch TS: a blue color is produced.
Heavy metals 231 Mix 2.0 g with water to make 25 mL: the limit is 0.001%.
Starch Dissolve 5 g in 50 mL of water, boil the solution for 1 minute, cool, and add 0.2 mL of 0.1 N iodine: no blue color is produced.
Assay for reducing sugars (dextrose equivalent)
Standard solution Dissolve an accurately weighed quantity of USP Dextrose RS in water, and dilute quantitatively with water to obtain a solution having a known concentration of about 6 mg per mL.
Test solution Transfer a quantity of Liquid Glucose, equivalent to about 3.0 g of reducing sugars (dextrose equivalent), to a 500-mL volumetric flask, dilute with water to volume, and mix.
Procedure Transfer 25.0-mL portions of alkaline cupric tartrate TS to each of two boiling flasks. Bring the contents of one flask to boiling within about 2 minutes while titrating with Standard solution to within 0.5 mL of the anticipated endpoint. Boil gently for 2 minutes. Continue to boil gently, add 2 drops of methylene blue solution (1 in 100), and complete the titration within 1 minute by adding the Standard solution dropwise or in small increments until the blue color disappears, determined by viewing against a white background in daylight or under equivalent illumination. If more than 0.5 mL of the titrant was required after the addition of the indicator, repeat the titration, adding the necessary volume of titrant before adding the indicator. Bring the contents of the second flask to boiling, and similarly titrate with the Test solution. Calculate the dextrose equivalent, on the anhydrous basis, taken by the formula:
[100 / (1 0.01A)] (500)(CS / W)(VS / VU)in which A is the percentage Water of the Liquid Glucose taken; 500 is the volume, in mL, of the Test solution; W is the weight, in mg, of Liquid Glucose taken to prepare the Test solution; CS is the concentration, in mg per mL, of USP Dextrose RS in the Standard solution; and VU and VS are the titrated volumes, in mL, of the Test solution and the Standard solution, respectively. The dextrose equivalent is not less than 90% and not more than 110% of the labeled value.
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USP35NF30 Page 1809Pharmacopeial Forum: Volume No. 33(6) Page 1248