» Calcium Ascorbate contains not less than 98.0 percent and not more than 101.0 percent of C12H14CaO12·2H2O, calculated on the as-is basis.
Packaging and storage Preserve in tight, light-resistant containers.
A: A solution (1 in 10) responds to the tests for Calcium 191.
B: A solution (1 in 10) decolorizes a solution of dichlorophenol-indophenol (1 in 10).
Specific rotation 781S: between +95 and +97, from optical rotation measurements made immediately following the preparation of the Test solution.
Test solution: 50 mg per mL, in carbon dioxide-free water.
pH 791: between 6.8 and 7.4 in a solution (1 in 10).
Loss on drying 731 Dry an accurately weighed quantity of about 3 g of it at 105 for 2 hours: it loses not more than 0.1% of its weight.
Arsenic, Method I 211: 3 µg per g.
Heavy metals, Method II 231: 0.001%.
Limit of fluoride Proceed as directed in the test for Limit of fluoride under Dibasic Calcium Phosphate: the limit is 10 ppm.
Assay Transfer an accurately weighed quantity of about 300 mg of Calcium Ascorbate to a 250-mL conical flask. Add 50 mL of water, mix to dissolve, and immediately titrate with 0.1 N iodine VS, adding 3 mL of starch TS as the endpoint is approached. Each mL of 0.1 N iodine is equivalent to 10.66 mg of C12H14CaO12·2H2O.
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USP32NF27 Page 1754Pharmacopeial Forum: Volume No. 27(6) Page 3255