Calcium Chloride

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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CaCl₂.2H₂O 147.01

Calcium chloride dihydrate CAS RN®: 10035-04-8.

CaCl₂ 110.98

Anhydrous CAS RN®: 10043-52-4.

1 DEFINITION

Calcium Chloride contains an amount of CaCl₂, equivalent to NLT 99.0% and NMT 107.0% of CaCl₂ .2H₂O.

2 IDENTIFICATION

A. IDENTIFICATION TESTS-GENERAL, Calcium (191)

Sample solution: 100 mg/mL

Acceptance criteria: Meets the requirements

B. IDENTIFICATION TESTS-GENERAL, Chloride (191)

Sample solution: 100 mg/mL

Acceptance criteria: Meets the requirements

3 ASSAY

PROCEDURE

Sample solution: Dissolve 1 g of Calcium Chloride in a mixture of water and 3 N hydrochloric acid (100:5). Transfer the solution to a 250-mL volumetric flask, and dilute with water to volume.

Analysis: Pipet 50 ml. of the Sample solution into a suitable container, and add 100 mL of water, 15 mL of 1 N sodium hydroxide, and 300 mg of hydroxy naphthol blue. Titrate with 0.05 M edetate disodium VS until the solution is deep blue. Each mL of 0.05 M edetate disodium is equivalent to 7.351 mg of calcium chloride dihydrate (CaCl₂.2H₂O).

Acceptance criteria: 99.0%-107.0% of CaCl₂.2H₂O

4 IMPURITIES

Change to read:

4.1 ALUMINUM (206), Procedure 1 (CN 1-Just-2023)

[NOTE-Perform if labeled as intended for use in hemodialysis.]

Test preparation: Use a 2.0-g sample.

Acceptance criteria: NMT 1 ppm.

4.2 IRON, ALUMINUM, AND PHOSPHATE

Sample solution: 50 mg/mL

Analysis: Add 2 drops of 3 N hydrochloric acid and 1 drop of phenolphthalein TS to the Sample solution. Then add ammonium chloride-ammonium hydroxide TS, dropwise, until the solution is faintly pink. Add 2 drops in excess, and heat the liquid to boiling.

Acceptance criteria: No turbidity or precipitate is produced.

4.3 LIMIT OF MAGNESIUM AND ALKALI SALTS

Sample solution: 20 mg/mL

Analysis: To 50 mL of Sample solution add 500 mg of ammonium chloride. Heat the solution, and boil for 1 min. Rapidly add 40 mL of oxalic acid TS, and stir vigorously until precipitation is well established. Add immediately to the warm mixture 2 drops of methyl red TS and then 6 N ammonium hydroxide, dropwise, until the mixture is just alkaline. Cool to room temperature. Transfer to a 100-ml graduated cylinder, dilute with water to 100 mL, mix, and allow to stand for 4 h or overnight. Filter, and to 50 mL of the clear filtrate in a platinum dish, add 0.5 mL of sulfuric acid, and evaporate the mixture on a steam bath to a small volume. Carefully heat over a free flame to dryness, and continue heating to complete decomposition and volatilization of ammonium salts. Finally, ignite the residue to constant weight.

Acceptance criteria: The weight of the residue is NMT 5 mg (1.0%).

5 SPECIFIC TESTS

PH (791)

Sample solution: 50 mg/mL

Acceptance criteria: 4.5-9.2

6 ADDITIONAL REQUIREMENTS

Packaging and Storage: Preserve in tight containers.

Labeling: Where Calcium Chloride is intended for use in hemodialysis, it is so labeled.