Baclofen 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

Baclofen Tablets contain NLT 90.0% and NMT 110.0% of the labeled amount of baclofen (C₁₀H₁₂ClNO₂).

2 IDENTIFICATION

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

B. The UV spectrum 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: 1.4 g/L of monobasic sodium phosphate and 1.7 g/L of sodium 1-pentanesulfonate in water. Adjust with 1.5 M phosphoric acid TS to a pH of 3.0.

Solution B: Acetonitrile and methanol (50:50)

Mobile phase: See Table 1.

Diluent: Solution A and Solution B (65:35)

Standard solution: 200 µg/mL of USP Baclofen RS in Diluent

Sample solution: Nominally 200 µg/mL of baclofen prepared as follows. Finely powder NLT 20 Tablets and transfer a portion of the powder to an appropriate volumetric flask. Add Diluent to about 80% of the flask volume, sonicate for 10 min, and shake by mechanical means for 30 min. Dilute with Diluent to volume. Centrifuge a portion of this solution and use the supernatant.

Chromatographic system

(See Chromatography 〈621〉, System Suitability.)

Mode: LC

Detector: UV 225 nm. For Identification B, use a diode array detector in the range of 200–400 nm.

Column: 4.6-mm × 25-cm; 5-µm packing L1

Column temperature: 35°

Flow rate: 0.8 mL/min

Injection volume: 10 µL

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 the labeled amount of baclofen (C₁₀H₁₂ClNO₂) in the portion of Tablets taken:

Result = (rᵤ/rₛ) × (Cₛ/Cᵤ) × 100

rᵤ = peak response from the Sample solution

rₛ = peak response from the Standard solution

Cₛ = concentration of USP Baclofen RS in the Standard solution (µg/mL)

Cᵤ = nominal concentration of baclofen in the Sample solution (µg/mL)

Acceptance criteria: 90.0%–110.0%

4 PERFORMANCE TESTS

Dissolution 〈711〉, Procedure, Apparatus 1 and Apparatus 2, Immediate-Release Dosage Forms, Procedure for a pooled sample for immediate-release dosage forms

Medium: 0.01 N hydrochloric acid; 500 mL for Tablets containing NMT 10 mg of baclofen; 1000 mL for Tablets containing more than 10 mg of baclofen

Apparatus 2: 50 rpm

Time: 30 min

Solution A: 62.7 g/L of sodium 1-pentanesulfonate in water

Mobile phase: Methanol, 0.3 N acetic acid, and Solution A (44:55:2)

Standard solution: USP Baclofen RS in Medium

Sample solution: Use a portion of the solution under test.

Chromatographic system

(See Chromatography 〈621〉, System Suitability.)

Mode: LC

Detector: UV 265 nm

Column: 3.9-mm × 30-cm; 10-µm packing L1

Flow rate: 0.6 mL/min

Injection volume: 190 µL

Run time: NLT 2 times the retention time of the baclofen peak

System suitability

Sample: Standard solution

Suitability requirements

Relative standard deviation: NMT 2.0%

Analysis

Samples: Standard solution and Sample solution

Calculate the percentage of the labeled amount of baclofen (C₁₀H₁₂ClNO₂) dissolved:

Result = (rᵤ/rₛ) × C × V × (1/L) × 100

rᵤ = peak response from the Sample solution

rₛ = peak response from the Standard solution

C = concentration of USP Baclofen RS in the Standard solution (mg/mL)

V = volume of Medium; 500 or 1000 mL

L = label claim (mg/Tablet)

Tolerances: NLT 75% (Q) of the labeled amount of baclofen (C₁₀H₁₂ClNO₂) is dissolved.

• Uniformity of Dosage Units 〈905〉: Meet the requirements

5 IMPURITIES

Organic Impurities

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

Standard solution: 0.4 µg/mL of USP Baclofen RS and 8 µg/mL of USP Baclofen Related Compound A RS in Diluent

System suitability

Sample: Standard solution

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

Suitability requirements

Tailing factor: NMT 1.5 for baclofen

Relative standard deviation: NMT 5.0% each for baclofen and baclofen related compound A

Analysis

Samples: Standard solution and Sample solution

Calculate the percentage of baclofen related compound A in the portion of Tablets taken:

Result = (rᵤ/rₛ) × (Cₛ/Cᵤ) × 100

rᵤ = peak response of baclofen related compound A from the Sample solution

rₛ = peak response of baclofen related compound A from the Standard solution

Cₛ = concentration of USP Baclofen Related Compound A RS in the Standard solution (µg/mL)

Cᵤ = nominal concentration of baclofen in the Sample solution (µg/mL)

Calculate the percentage of any individual degradation product in the portion of Tablets taken:

Result = (rᵢ/r_b) × (Cₛ/Cᵤ) × 100

rᵢ = peak response of any individual degradation product from the Sample solution

r_b= peak response of baclofen from the Standard solution

Cₛ = concentration of USP Baclofen RS in the Standard solution (µg/mL)

Cᵤ = nominal concentration of baclofen in the Sample solution (µg/mL)

Acceptance criteria: See Table 2.

a Baclofen related compound A is not included in the total degradation products.

6 ADDITIONAL REQUIREMENTS

Packaging and Storage: Preserve in well-closed containers. Store at controlled room temperature.

USP Reference Standards 〈11〉

USP Baclofen RS

USP Baclofen Related Compound A RS

4-(4-Chlorophenyl)-2-pyrrolidinone.

C₁₀H₁₀ClNO 195.65