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Calcium Lactobionate
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C24H42CaO24·2H2O 790.68

D-Gluconic acid, 4-O--D-galactopyranosyl-, calcium salt (2:1), dihydrate.
Lactobionic acid, calcium salt (2:1), dihydrate.
Calcium lactobionate (1:2), dihydrate [110638-68-1].
» Calcium Lactobionate contains not less than 96.0 percent and not more than 102.0 percent of C24H42CaO24·2H2O.
Packaging and storage— Preserve in well-closed containers.
Identification—
A: A solution (1 in 50) responds to the tests for Calcium 191.
C: Dissolve a quantity of it in water to obtain a test solution containing 10 mg per mL. Similarly prepare a Standard solution of USP Calcium Lactobionate RS in water containing 10 mg per mL. Apply separately 5 µL of the test solution and 5 µL of the Standard solution to a suitable thin-layer chromatographic plate (see Chromatography 621) coated with a 0.25-mm layer of chromatographic silica gel. Dry the plate in a current of cool air. Place the plate in a suitable chromatographic chamber lined with filter paper and previously equilibrated with a solvent system consisting of a mixture of alcohol, water, ethyl acetate, and ammonium hydroxide (50:30:10:10). Develop the chromatogram until the solvent front has moved about three-fourths of the length of the plate. Remove the plate from the chamber, and dry at 100 for 20 minutes. Allow to cool, and spray with a spray reagent prepared as follows. Dissolve 2.5 g of ammonium molybdate in about 50 mL of 2 N sulfuric acid in a 100-mL volumetric flask, add 1.0 g of ceric sulfate, swirl to dissolve, dilute with 2 N sulfuric acid to volume, and mix. Heat the plate at 110 for about 10 minutes: the principal spot obtained from the test solution corresponds in color, size, and RF value to that obtained from the Standard solution.
Specific rotation 781S: between +22.0 and +26.5.
Test solution: 100 mg per mL, in water.
pH 791: between 5.4 and 7.4, in a solution (1 in 20).
Halides— A 1.2-g portion tested as directed under Chloride 221 shows no more turbidity than corresponds to 0.7 mL of 0.020 N hydrochloric acid (0.04%).
Sulfate 221— A 2.0-g portion dissolved in boiling water shows no more sulfate than corresponds to 1 mL of 0.020 N sulfuric acid (0.05%).
Heavy metals 231— Mix 1 g with 4 mL of 1.2 N hydrochloric acid, add water to make 25 mL, warm gently until dissolved, and cool to room temperature: the limit is 0.002%.
Reducing substances— Transfer 1.0 g to a 250-mL conical flask, dissolve in 20 mL of water, and add 25 mL of alkaline cupric citrate TS. Cover the flask, boil gently for 5 minutes, accurately timed, and cool rapidly to room temperature. Add 25 mL of 0.6 N acetic acid, 10.0 mL of 0.1 N iodine VS, and 10 mL of 3 N hydrochloric acid, and titrate with 0.1 N sodium thiosulfate VS, adding 3 mL of starch TS as the endpoint is approached. Perform a blank determination, omitting the specimen, and note the difference in volumes required. Each mL of the difference in volume of 0.1 N sodium thiosulfate consumed is equivalent to 2.7 mg of reducing substances (as dextrose): the limit is 1.0%.
Residual solvents 467: meets the requirements.
(Official January 1, 2007)
Assay— Dissolve about 0.8 g of Calcium Lactobionate, accurately weighed, in a mixture of water and 3 N hydrochloric acid (150:2). While stirring with a magnetic stirrer, add about 15 mL of 0.05 M edetate disodium VS from a 50-mL buret. Add 15 mL of 1 N sodium hydroxide and 300 mg of hydroxy naphthol blue, and continue the titration to a blue endpoint. Each mL of 0.05 M edetate disodium is equivalent to 39.53 mg of C24H42CaO24·2H2O.
Auxiliary Information— Staff Liaison : Lawrence Evans, III, Ph.D., Scientist
Expert Committee : (DSN05) Dietary Supplements - Non-Botanicals
USP29–NF24 Page 357
Pharmacopeial Forum : Volume No. 27(6) Page 3260
Phone Number : 1-301-816-8389