Carbinoxamine Maleate

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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C₁₆H₁₉ClN₂O · C₄H₄O₄ 406.86

Ethanamine, 2-[(4-chlorophenyl)-2-pyridinylmethoxy]-N,N-dimethyl-, (Z)-2-butenedioate (1:1);

2-[p-Chloro-α-[2-(dimethylamino)ethoxy]benzyl]pyridine maleate (1:1) CAS RN®: 3505-38-2.

1 DEFINITION

Carbinoxamine Maleate contains NLT 98.0% and NMT 102.0% of carbinoxamine maleate (C₁₆H₁₉ClN₂O · C₄H₄O₄), calculated on the dried basis.

2 IDENTIFICATION

Change to read:

A. Spectroscopic Identification Tests 〈197〉, Infrared Spectroscopy: 197A or 197K (CN 1-May-2020)

B. The UV spectrum of the major peak of the Sample solution corresponds to that of the Standard solution, as obtained in the Assay.

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

3 ASSAY

3.1 Procedure

Solution A: 2.72 g/L of monobasic potassium phosphate. Adjust with phosphoric acid to a pH of 4.0.

Solution B: Methanol and acetonitrile (80:20)

Mobile phase: See Table 1.

Table 1

Diluent: Methanol, acetonitrile, and water (200:50:750)

System suitability solution: 0.1 mg/mL of USP Carbinoxamine Maleate RS and 0.01 mg/mL each of USP Carbinoxamine Related Compound

A RS and USP Carbinoxamine Related Compound B RS in Diluent

Standard solution: 0.1 mg/mL of USP Carbinoxamine Maleate RS in Diluent

Sample solution: 0.1 mg/mL of Carbinoxamine Maleate in Diluent

3.2 Chromatographic system

(See Chromatography 〈621〉, System Suitability.)

Mode: LC

Detector: UV 225 nm. For Identi

cation B, use a diode array detector in the range of 200–400 nm.

Column: 4.6-mm × 15-cm; 5-μm packing L7

Column temperature: 40°

Flow rate: 1 mL/min

Injection volume: 10 μL

3.3 System suitability

Samples: System suitability solution and Standard solution

[Note—See Table 2 for relative retention times.]

3.4 Suitability requirements

Resolution: NLT 4.0 between carbinoxamine related compound A and carbinoxamine related compound B, System suitability solution

Tailing factor: NMT 1.5, Standard solution

Relative standard deviation: NMT 0.73%, Standard solution

3.5 Analysis

Samples: Standard solution and Sample solution

Calculate the percentage of carbinoxamine maleate (C₁₆H₁₉ClN₂O · C₄H₄O₄) in the portion of Carbinoxamine Maleate taken:

Result = (r_U/r_S) x (C_S/C_U) × 100

r_U = peak response of carbinoxamine from the Sample solution

r_S = peak response of carbinoxamine from the Standard solution

C_S = concentration of USP Carbinoxamine Maleate RS in the Standard solution (mg/mL)

C_U = concentration of Carbinoxamine Maleate in the Sample solution (mg/mL)

Acceptance criteria: 98.0%–102.0% on the dried basis

4 IMPURITIES

Residue on Ignition 〈281〉: NMT 0.1%

Organic Impurities

Solution A, Solution B, Mobile phase, Diluent, System suitability solution, and Chromatographic system: Proceed as directed in the Assay.

Standard stock solution: 0.07 mg/mL of USP Carbinoxamine Maleate RS (equivalent to 0.05 mg/mL of carbinoxamine) and 0.05 mg/mL each of USP Carbinoxamine Related Compound A RS, USP Carbinoxamine Related Compound B RS, and USP Carbinoxamine Related Compound C RS (as the free base) in Diluent

Standard solution: 0.0014 mg/mL of USP Carbinoxamine Maleate RS (equivalent to 0.001 mg/mL of carbinoxamine) and 0.001 mg/mL each of USP Carbinoxamine Related Compound A RS, USP Carbinoxamine Related Compound B RS, and USP Carbinoxamine Related Compound C RS (as the free base) in Diluent, from Standard stock solution

Sample solution: 1.0 mg/mL of Carbinoxamine Maleate in Diluent

System suitability

Samples: System suitability solution and Standard solution

[Note—See Table 2 for relative retention times.]

Suitability requirements

Resolution: NLT 4.0 between carbinoxamine related compound A and carbinoxamine related compound B, System suitability solution

Relative standard deviation: NMT 5.0% for each corresponding compound, Standard solution

Analysis

Samples: Standard solution and Sample solution

Calculate the percentage of carbinoxamine related compound A, carbinoxamine related compound B, and carbinoxamine related compound C in the portion of Carbinoxamine Maleate taken:

Result = (r_U/r_S) x (C_S/C_U) × 100

r_U = peak response of carbinoxamine related compound A, carbinoxamine related compound B, or carbinoxamine related compound C from the Sample solution

r_S = peak response of the corresponding Reference Standard from the Standard solution

C_S = concentration of the corresponding Reference Standard in the Standard solution (mg/mL)

C_U = concentration of Carbinoxamine Maleate in the Sample solution (mg/mL)

Calculate the percentage of any other individual unspecified impurity in the portion of Carbinoxamine Maleate taken:

Result = (r_U/r_S) x (C_S/C_U) × 100

r_U = peak response of any other individual unspecified impurity from the Sample solution

r_S = peak response of carbinoxamine from the Standard solution

C_S = concentration of USP Carbinoxamine Maleate RS (as the free base) in the Standard solution (mg/mL)

C_U = concentration of Carbinoxamine Maleate in the Sample solution (mg/mL)

Acceptance criteria: See Table 2.

Table 2

5 SPECIFIC TESTS

pH 〈791〉

Sample: In a solution (1 in 100)

Acceptance criteria: 4.6–5.1

Loss on Drying 〈731〉

Analysis: Dry at 105° for 2 h.

Acceptance criteria: NMT 0.5%

6 ADDITIONAL REQUIREMENTS

Packaging and Storage: Preserve in tight, light-resistant containers.

USP Reference Standards 〈11〉

USP Carbinoxamine Maleate RS

USP Carbinoxamine Related Compound A RS

(4-Chlorophenyl)(pyridin-2-yl)methanone.

C₁₂H₈ClNO 217.65

USP Carbinoxamine Related Compound B RS

(4-Chlorophenyl)(pyridin-2-yl)methanol.

C₁₂H₁₀ClNO 219.67

USP Carbinoxamine Related Compound C RS

N,N-Dimethyl-2-[phenyl(pyridin-2-yl)methoxy]ethan-1-amine oxalate.

C₁₆H₂₀N₂O · C₂H₂O₄ 346.38