Amoxapine Tablets

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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1 DEFINITION

Amoxapine Tablets contain NLT 90.0% and NMT 110.0% of the labeled amount of amoxapine (C₁₇H₁₆ClN₃O).

2 IDENTIFICATION

Change to read:

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

Sample: Triturate a quantity of finely ground Tablets, equivalent to 50 mg of amoxapine, with 10 mL of chloroform, and filter. Evaporate the filtrate on a steam bath to dryness (about 30 min).

B. 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

Procedure

Solution A: 1.38 g/L of monobasic sodium phosphate in water

Solution B: 113 g/L of tetramethylammonium chloride in water

Mobile phase: Transfer 20.0 mL of Solution B, 4.0 mL of dilute phosphoric acid (1 in 5), and 720 mL of acetonitrile to a 2000-mL volumetric ask. Dilute with Solution A to volume.

Standard stock solution: 1 mg/mL of USP Amoxapine RS in acetonitrile. Shake by mechanical means to dissolve, and then dilute with acetonitrile to volume.

Standard solution: 0.1 mg/mL from the Standard stock solution diluted with Mobile phase

Sample stock solution: Nominally 1 mg/mL of amoxapine from NLT 20 finely powdered Tablets prepared as follows. Transfer a suitable quantity of the powder to a volumetric ask. Add 80% of the ask volume of Mobile phase, and shake vigorously by mechanical means for 20 min. Dilute with Mobile phase to volume, and filter.

Sample solution: 0.1 mg/mL from the Sample stock solution diluted with Mobile phase

3.1 Chromatographic system

(See Chromatography 〈621〉, System Suitability.)

Mode: LC

Detector: UV 254 nm

Column: 4.6-mm × 25-cm; packing L1

Flow rate: 1.5 mL/min

Injection volume: 10 µL

3.2 System suitability

Sample: Standard solution

Suitability requirements

Column efficiency: NLT 1200 theoretical plates

Tailing factor: NMT 1.8

Relative standard deviation: NMT 2.0%

3.3 Analysis

Samples: Standard solution and Sample solution

Calculate the percentage of the labeled amount of amoxapine (C₁₇H₁₆ClN₃O) in the portion of Tablets taken:

Result = (r_U /r_S) × (C_S /C_U) × 100

r_U = peak response of amoxapine from the Sample solution

r_S = peak response of amoxapine from the Standard solution

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

C_U = nominal concentration of amoxapine in the Sample solution (mg/mL)

Acceptance criteria: 90.0%–110.0%

4 PERFORMANCE TESTS

Dissolution 〈711〉

Medium: Simulated gastric uid (without enzyme); 900 mL

Apparatus 2: 50 rpm

Time: 30 min

Sample solution: Sample per Dissolution 〈711〉.

Standard solution: USP Amoxapine RS having a concentration similar to the expected Sample solution in Medium Instrumental conditions

Analytical wavelength: 294 nm

Analysis

Samples: Sample solution and Standard solution

Determine the percentage of the labeled amount of amoxapine (C₁₇H₁₆ClN₃O) dissolved from UV absorbances of filtered portions of the Sample solution, suitably diluted with Medium, if necessary.

Calculate the percentage of the labeled amount of amoxapine (C₁₇H₁₆ClN₃O) dissolved:

Result = (A_U /A_S ) × C_S × V × (1/L) × 100

A_U = absorbance of the Sample solution

A_S = absorbance of the Standard solution

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

V = volume of the Medium, 900 mL

L = label claim (mg/Tablet)

Tolerances: NLT 80% (Q) of the labeled amount of amoxapine (C₁₇H₁₆ClN₃O) is dissolved.

Uniformity of Dosage Units 〈905〉: Meet the requirements

5 ADDITIONAL REQUIREMENTS

Packaging and Storage: Preserve in well-closed containers.

USP Reference Standards 〈11〉

USP Amoxapine RS