Paroxetine 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

Paroxetine Tablets contain an amount of Paroxetine Hydrochloride equivalent to NLT 90.0% and NMT 110.0% of the labeled amount of paroxetine (C₁₉H₂₀FNO₃).

2 IDENTIFICATION

Change to read:

A. Spectroscopic Identification Tests 〈197〉, Infrared Spectroscopy: 197K

Sample: Transfer a quantity of finely powdered Tablets, equivalent to 90 mg of paroxetine, to a suitable flask. Add 100 mL of 0.1 N hydrochloric acid, and stir for 1 h. Transfer the mixture to a separatory funnel, and add 1.5 mL of ammonium hydroxide to make the solution alkaline. Add 100 mL of ethyl ether to the funnel, and shake for 2 min. Transfer the organic layer into the necessary number of centrifuge tubes, and centrifuge for 10 min. Recombine the clarified extracts, add 1 drop of water and 0.5 mL of hydrochloric acid, stir, and evaporate to dryness under a stream of nitrogen. Dry the residue in an oven at 90° for 1 h.

Acceptance criteria: Meet the requirements

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

3 ASSAY

Procedure

Buffer: Water, phosphoric acid, and triethylamine (100:0.6:0.3)

Mobile phase: Acetonitrile and Buffer (30:70)

Standard solution: 0.1 mg/mL of USP Paroxetine Hydrochloride RS in methanol

Sample stock solution: 0.5 mg/mL of paroxetine from NLT 20 Tablets in methanol prepared as follows. Transfer an amount of finely powdered Tablets equivalent to NLT 100 mg of paroxetine to a suitable volumetric flask. Dissolve in methanol. Dilute with methanol to volume. Centrifuge a portion of the solution for 6 min. Use the supernatant.

Sample solution: Nominally 0.1 mg/mL of paroxetine in methanol, from the Sample stock solution

3.1 Chromatographic system

(See Chromatography 〈621〉, System Suitability.)

Mode: LC

Detector: UV 295 nm

Column: 4.6-mm × 3.3-cm; 3-µm packing L7

Flow rate: 2 mL/min

Injection volume: 5 µL

3.2 System suitability

Sample: Standard solution

Suitability requirements

Column efficiency: NLT 750 theoretical plates

Tailing factor: NMT 4

Relative standard deviation: NMT 2.0% for paroxetine

3.3 Analysis

Samples: Standard solution and Sample solution

Calculate the percentage of the labeled amount of paroxetine (C₁₉H₂₀FNO₃) in the portion of Tablets taken:

Result = (r_U /r_S ) × (C_S /C_U) × (M_r1 /M_r2 ) × 100

r_U = peak response from the Sample solution

r_S = peak response from the Standard solution

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

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

M_r1 = molecular weight of paroxetine, 329.37

M_r2 = molecular weight of paroxetine hydrochloride, 365.83

Acceptance criteria: 90.0%–110.0%

4 PERFORMANCE TESTS

Dissolution 〈711〉

Medium: Simulated gastric uid without enzyme; 900 mL

Apparatus 2: 60 rpm

Time: 60 min

Buffer and Mobile phase: Proceed as directed in the Assay.

Standard stock solution: 0.63 mg/mL of USP Paroxetine Hydrochloride RS in Medium prepared as follows. Transfer a suitable quantity of USP Paroxetine Hydrochloride RS to a suitable volumetric flask. Add 5% of the ask volume of methanol, and dissolve. Dilute with Medium to volume.

Sample solution: Pass the solution under test through a suitable membrane filter of 0.45-µm pore size.

Standard solution: Quantitatively dilute the Standard stock solution with Medium to a concentration near that of the Sample solution.

4.1 Chromatographic system

(See Chromatography 〈621〉, System Suitability.)

Mode: LC

Detector: UV 295 nm

Column: 4.6-mm × 3.3-cm; 3-µm packing L7

Flow rate: 2 mL/min

Injection volume: 20 µL

4.2 System suitability

Sample: Standard solution

Suitability requirements

Column efficiency: NLT 750 theoretical plates

Tailing factor: NMT 4

Relative standard deviation: NMT 2.0% for paroxetine

4.3 Analysis

Samples: Sample solution and Standard solution

Calculate the percentage of the labeled amount of paroxetine (C₁₉H₂₀FNO₃) dissolved based on the peak responses obtained from the Sample solution and the Standard solution.

Tolerances: NLT 80% (Q) of the labeled amount of paroxetine (C₁₉H₂₀FNO₃) is dissolved.

Change to read:

Uniformity of Dosage Units 〈905〉: Meet the requirements (CN 1-Aug-2023)

Buffer, Mobile phase, Standard solution, Chromatographic system, and System suitability: Proceed as directed in the Assay. Sample solution: Nominally 0.1 mg/mL of paroxetine prepared as follows. Place 1 Tablet in a suitable volumetric flask, and add a volume of a hydrochloric acid solution (7 in 1000), equivalent to about 25% of the ask volume. Allow the Tablet to disintegrate. Dilute with methanol to volume. Centrifuge a portion of the solution.

Analysis

Samples: Standard solution and Sample solution

Calculate the percentage of the labeled amount of paroxetine (C₁₉H₂₀FNO₃) in the Tablet taken:

Result = (r_U /r_S ) × C_S × (M_r1 /M_r2) × V

r_U = peak response from the Sample solution

r_S = peak response from the Standard solution

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

M_r1 = molecular weight of paroxetine, 329.37

M_r2 = molecular weight of paroxetine hydrochloride, 365.83

V = volume of the Sample solution (mL)

Acceptance criteria: Meet the requirements

(CN 1-Aug-2023)

5 ADDITIONAL REQUIREMENTS

Packaging and Storage: Preserve in tight containers, and store at controlled room temperature.

USP Reference Standards 〈11〉

USP Paroxetine Hydrochloride RS