Calcium Lactobionate

This article is compiled based on the United States Pharmacopeia (USP) – 2025 Edition

Issued and maintained by the United States Pharmacopeial Convention (USP)

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C₂₄H₄₂CaO₂₄.2H₂O.  790.68

D-Gluconic acid, 4-0-B-D-galactopyranosyl-, calcium salt (2:1), dihydrate;

Lactobionic acid, calcium salt (2:1), dihydrate;

Calcium lactobionate (1:2), dihydrate CAS RN®: 110638-68-1; UNII: 7D8YVA497F.

1 DEFINITION

Calcium Lactobionate contains NLT 96.0% and NMT 102.0% of calcium lactobionate (C₂₄H₄₂CaO₂₄.2H₂O).

2 IDENTIFICATION

A. IDENTIFICATION TESTS GENERAL, Calcium (191): A 20 mg/mL solution meets the requirements.

Change to read:

B. SPECTROSCOPIC IDENTIFICATION TESTS (197), Infrared Spectroscopy: 197K (CN 1-MAY-2020)

C. THIN LAYER CHROMATOGRAPHY

Standard solution: 10 mg/mL of USP Calcium Lactobionate RS in water

Sample solution: 10 mg/mL of Calcium Lactobionate in water

Chromatographic system

(See Chromatography (621). Thin-Layer Chromatography.)

Mode: TLC

Adsorbent: 0.25-mm layer of chromatographic silica gel

Application volume: 5 µL

Developing solvent system: Alcohol, ethyl acetate, ammonium hydroxide, and water (50:10:10:30)

Spray reagent: Dissolve 2.5 g of ammonium molybdate in 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.

Analysis:

Samples: Standard solution and Sample solution

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 min. Allow to cool, and spray with the Spray reagent. Heat the plate at 110° for about 10 min.

Acceptance criteria: The principal spot of the Sample solution corresponds in color, size, and R, value to that of the Standard solution.

3 ASSAY

PROCEDURE

Sample: 800 mg of Calcium Lactobionate

Blank: 150 mL of water and 2 mL of 3 N hydrochloric acid

Titrimetric system

(See Titrimetry (541).)

Mode: Direct titration

Titrant: 0.05 M edetate disodium VS

Endpoint detection: Visual

Analysis: Dissolve the Sample in a mixture of water and 3 N hydrochloric acid (150:2). While stirring with a magnetic stirrer, add 15 mL of Titrant from the titration buret. Add 15 mL of 1 N sodium hydroxide and 300 mg of hydroxy naphthol blue, and continue the titration to a blue endpoint. Perform the Blank determination.

Calculate the percentage of calcium lactobionate (C₂₄H₄₂CaO₂₄.2H₂O) in the Sample taken:

Result={[(V_S-V_B)xMxF]/W}×100

V_S = Titrant volume consumed by the Sample (mL)

V_B = Titrant volume consumed by the Blank (mL)

M = Titrant molarity (mM/mL)

F = equivalency factor, 790.7 mg/mmol

W = Sample weight (mg)

Acceptance criteria: 96.0%-102.0%

4 IMPURITIES

4.1 HALIDES

Standard solution: 0.7 ml. of 0.020 N hydrochloric acid

Sample: 1.2 g

Analysis: Proceed as directed for Chloride and Sulfate (221). Chloride

Acceptance criteria: NMT 0.04% CHLORIDE AND SULFATE, Sulfate (221)

Standard solution: 1 mL of 0.020 N sulfuric acid

Sample: 2.0 g

Analysis: Dissolve the Sample in boiling water.

Acceptance criteria: NMT 0.05%

4.2 REDUCING SUBSTANCES

Sample: 1.0 g of Calcium Lactobionate

Blank: 20 mL of water

Titrimetric system (See Titrimetry (541).)

Mode: Residual titration

Titrant: 0.1 N iodine VS

Back-titrant: 0.1 N sodium thiosulfate VS

Endpoint detection: Visual

Analysis: Transfer the Sample to a 250-mL conical flask, dissolve in the Blank, and add 25 mL of alkaline cupric citrate TS. Cover the flask, boil gently for 5 min, accurately timed, and cool rapidly to room temperature. Add 25 mL of 0.6 N acetic acid, 10.0 mL of Titrant, and 10 ml of 3 N hydrochloric acid, and titrate with Back-titrant, adding 3 mL of starch TS as the endpoint is approached. Perform the Blank determination. Calculate the percentage of reducing substances (as dextrose) in the Sample taken:

Result= ([(V_B-V_S)xNxF]/W}×100

V_B = Back-titrant volume consumed by the Blank (mL)

V_S = Back-titrant volume consumed by the Sample (mL)

N = Back-titrant normality (mEq/mL)

F = equivalency factor, 27 mg/mEq

W = Sample weight (mg)

Acceptance criteria: NMT 1.0%

5 SPECIFIC TESTS

OPTICAL ROTATION, Specific Rotation(781S)

Sample solution: 100 mg/mL

Acceptance criteria: +22.0° to +26.5"

PH (791)

Sample solution: 50 mg/mL

Acceptance criteria: 5.4-7.4

6 ADDITIONAL REQUIREMENTS

PACKAGING AND STORAGE: Preserve in well-closed containers.

USP REFERENCE STANDARDS (11)

USP Celcium Lactobionate RS