Calcium Undecylenate

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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C₂₂H₃₈O₄Ca    406.62

10-Undecenoic acid, calcium (2+) salt;

Calcium 10-undecenoate CAS RN: 1322-14-1; UNII: 77YW1RTU8V.

1 DEFINITION

Calcium Undecylenate contains NLT 98.0% and NMT 102.0% of calcium undecylenate (C₂₂H₃₈O₄Ca), calculated on the dried basis.

2 IDENTIFICATION

A. IDENTIFICATION TESTS-GENERAL (191), Chemical Identification Tests, Calcium

Sample solution: 50 mg/mL of Calcium Undecylenate in 3 N hydrochloric acid. Pass through a suitable filter.

Acceptance criteria: Meets the requirements

B. SPECTROSCOPIC IDENTIFICATION TESTS (197), Infrared Spectroscopy: 197A

C. The retention time of the Undecylenic Acid peak of the Sample solution corresponds to that of the Standard solution, as obtained in the Assay.

3 ASSAY

Change to read:

PROCEDURE

Solution A: 0.15 N hydrochloric acid in water prepared as follows. Transfer 150 mL of 0.5 N hydrochloric acid VSA (ERR 1-Nov-2022) to a 500-mL volumetric flask, dilute with water to volume, and mix well.

Standard solution: 0.5 mg/ml. of USP Undecylenic Acid RS in n-heptane, prepared as follows. Accurately weigh and transfer 25 mg of USP Undecylenic Acid RS to a suitable flask, add 20 mL of Solution A, and heat until the sample is liquified and transparent with two immiscible layers. Cool, upon which turbidity may be observed. Add 50 mL of n-heptane to the flask, and mix well. Transfer the n-heptane layer to a suitable container, and dry over anhydrous sodium sulfate. Centrifuge to clarify the mixture, and use the clear supernatant.

Sample solution: Nominally 0.5 mg/mL of undecylenic acid in n-heptane, prepared as follows. Accurately weigh and transfer 27.6 mg of Calcium Undecylenate, equivalent to 25 mg of undecylenic acid, to a suitable flask. Follow the preparation steps described in the Standard solution.

Chromatographic system

(See Chromatography (621), System Suitability.)

Mode: GC

Detector: Flame ionization

Column: 0.25-mm x 30-m fused-silica capillary; coated with a 0.25-µm film of phase G35

Temperatures

Injection port: 280°

Detector: 350*

Column: See Table 1.

Table 1

Carrier gas: Helium

Flow rate: 0.7 mL/min

Injection volume: 1 L

Injection type: Split, split ratio 25:1

System suitability

Sample: Standard solution

Suitability requirements

Tailing factor: NMT 2.0

Relative standard deviation: NMT 1.0%

Analysis

Samples: Standard solution and Sample solution

Calculate the percentage of calcium undecylenate (C₂₂H₃₈O₄Ca) in the portion of Calcium Undecylenate taken:

Result = (r_U/r_S)x(C_S/C_U)×[M_r1/(2xM_r2)] × 100

r_U = peak response of undecylenic acid from the Sample solution

r_S = peak response of undecylenic acid from the Standard solution

C_S = concentration of USP Undecylenic Acid RS in the Standard solution (mg/mL) 

C_U = concentration of Calcium Undecylenate in the Sample solution (mg/mL)

M_r1 = molecular weight of calcium undecylenate, 406.62

M_r2 = molecular weight of undecylenic acid, 184.28

Acceptance criteria: 98.0%~102.0% on the dried basis.

4 IMPURITIES

LIMIT OF FREE UNDECYLENIC ACID

Sensitivity solution: 0.005 mg/mL of USP Undecylenic Acid RS in n-heptane

Standard solution: 0.01 mg/ml. of USP Undecylenic Acid RS in n-heptane

Sample solution: 10 mg/ml. of Calcium Undecylenate in n-heptane prepared as follows. Accurately weigh and transfer 100 mg of Calcium Undecylenate into a suitable container, add 10 mL of n-hentane, and mix for 2 h by magnetic stirring. Centrifuge to clarify the mixture, and use the clear supernatant.

Chromatographic system: Proceed as directed in the Assay except for the Injection type.

Injection type: Split, split ratio 10:1

System suitability

Samples: Sensitivity solution and Standard solution

Suitability requirements

Relative standard deviation: NMT 5.0%, Standard solution

Signal-to-noise ratio: NLT 10, Sensitivity solution

Analysis

Samples: Standard solution and Sample solution

Result = (r_U/r_S)x(C_S/C_U)) ×100

Calculate the percentage of undecylenic acid (C₁₁H₂₀O₂) in the portion of Calcium Undecylenate taken:

r_U = peak response of undecylenic acid from the Sample solution

r_S = peak response of undecylenic acid from the Standard solution

C_S = concentration of USP Undecylenic Acid RS in the Standard solution (mg/mL)

C_U = concentration of Calcium Undecylenate in the Sample solution (mg/mL)

Acceptance criteria: NMT 0.1%

5 SPECIFIC TESTS

5.1 LOSS ON DRYING (731)

Analysis: Dry at 105° for 2 h.

Acceptance criteria: 2.0%-5.7%

5.2 PARTICLE SIZE DISTRIBUTION ESTIMATION BY ANALYTICAL SIEVING (786)

Analysis: Test in accordance with this procedure, except use NMT 25 g and use a single No. 100 sieve that is to be shaken for NLT 30 min or until sifting is practically complete.

Acceptance criteria: NLT 99.0% of it passes through a No. 100 sieve

6 ADDITIONAL REQUIREMENTS

Packaging and Storage: Preserve in well-closed containers.

USP Reference Standards 〈11〉

USP Calcium Undecylenate RS

USP Undecylenic Acid RS