Gabapentin Tablets

This article is compiled based on the United States Pharmacopeia (USP) – 2025 Edition

Issued and maintained by the United States Pharmacopeial Convention (USP)

DOWNLOAD PDF HERE

1 DEFINITION

Gabapentin Tablets contain NLT 90.0% and NMT 110.0% of the labeled amount of gabapentin (C₉H₁₇NO₂).

2 IDENTIFICATION

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

Sample: Grind at least 20 Tablets to a ne powder. Use an amount of powder equivalent to 2 mg of gabapentin and 200 mg of dry potassium bromide.

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

Diluent: 1.2 g/L of monobasic potassium phosphate in water. Adjust with 5 N potassium hydroxide to a pH of 6.9. Mobile phase: Dissolve 1.2 g of monobasic potassium phosphate in 940 mL of water. Adjust with 5 N potassium hydroxide to a pH of 6.9. Add 60 mL of acetonitrile, and stir. Filter and degas.

Standard solution: 4.0 mg/mL of USP Gabapentin RS in Diluent

Sample solution: 4.0 mg/mL of gabapentin from NLT 20 finely powdered Tablets in Diluent

3.1 Chromatographic system

(See Chromatography 〈621〉, System Suitability.)

Mode: LC

Detector: UV 210 nm

Column: 4.6-mm × 25-cm; 5-µm packing L7

Flow rate: 1.2 mL/min

Injection size: 50 µL

3.2 System suitability

Sample: Standard solution

Suitability requirements

Column efficiency: NLT 7000 theoretical plates

Tailing factor: NMT 2.0

Relative standard deviation: NMT 2.0% of gabapentin

3.3 Analysis

Samples: Standard solution and Sample solution

Calculate the percentage of the labeled amount of C₉H₁₇NO₂ in the portion of Tablets taken:

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

r_U = peak response from the Sample solution

r_S = peak response from the Standard solution

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

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

Acceptance criteria: 90.0%–110.0%

4 PERFORMANCE TESTS

Change to read:

Dissolution 〈711〉

4.1 Test 1

Medium: 0.06 N hydrochloric acid (51 mL of hydrochloric acid in 10 L of water); 900 mL

Apparatus 2: 50 rpm

Time: 45 min

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

Determine the amount of C₉H₁₇NO₂ dissolved by using the following method.

Mobile phase: Prepare as directed in the Assay.

Standard solution: 0.0011 × L mg/mL of USP Gabapentin RS in the Medium, where L is the label claim in mg/Tablet

Chromatographic system: Proceed as directed for the Assay.

Injection size: 100 µL for the Tablets labeled to contain 100, 300, or 400 mg; 50 µL for Tablets labeled to contain 600 or 800 mg

4.1.1 System suitability

Sample: Standard solution

Suitability requirements

Column efficiency: NLT 5000 theoretical plates

Tailing factor: NMT 2.0

Relative standard deviation: NMT 3%

4.1.2 Analysis

Samples: Standard solution and Sample solution

Calculate the percentage of C₉H₁₇NO₂ dissolved:

Result = (r_U /r_S) × C_S × (V/L) × 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)

V = volume of the Medium, 900 mL

L = Tablet label claim in mg

Tolerances: NLT 80% (Q) of the labeled amount of C₉H₁₇NO₂ is dissolved.

4.2 Test 2 

If the product complies with this test, the labeling indicates that the product meets USP Dissolution Test 2. Medium, Apparatus 2, Mobile phase, Standard solution, Sample solution, Chromatographic system, and Analysis: Proceed as directed for Test 1.

Time: 30 min

Tolerances: NLT 80% (Q) of the labeled amount of C₉H₁₇NO₂ is dissolved.

4.3 Test 3

If the product complies with this test, the labeling indicates that it meets USP Dissolution Test 3.

Medium: 0.1 N hydrochloric acid; 500 mL, deaerated, if necessary

Apparatus 2: 50 rpm

Time: 30 min

Buffer: Dissolve 1.2 g of monobasic potassium phosphate in 940 mL of water. Adjust with 5 N potassium hydroxide to a pH of 6.9. Mobile phase: Acetonitrile and Buffer (60:940)

Standard solution: (L/500) mg/mL of USP Gabapentin RS in Medium, where L is the label claim in mg/Tablet. Sonicate to dissolve, if necessary.

Sample solution: Pass a portion of the solution under test through a suitable filter of 0.45-μm pore size, discarding an appropriate volume of filtrate so that a consistent result can be obtained.

4.3.1 Chromatographic system

(See Chromatography 〈621〉, System Suitability.)

Mode: LC

Detector: UV 210 nm

Column: 4.6-mm × 25-cm; 5-µm packing L7

Flow rate: 1.2 mL/min

Injection volume: 10 µL

Run time: NLT 2.3 times the retention time of gabapentin

4.3.2 System suitability

Sample: Standard solution

Suitability requirements

Tailing factor: NMT 2.0

Relative standard deviation: NMT 2.0%

4.3.3 Analysis

Samples: Standard solution and Sample solution

Calculate the percentage of gabapentin (C₉H₁₇NO₂) dissolved:

Result = (r_U /r_S) × C_S × V × (1/L) × 100

r_U = peak response of gabapentin from the Sample solution

r_S = peak response of gabapentin from the Standard solution

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

V = volume of Medium, 500 mL

L = label claim (mg/Tablet)

Tolerances: NLT 80% (Q) of the labeled amount of gabapentin (C₉H₁₇NO₂) is dissolved. (RB 1-Jan-2025)

Uniformity of Dosage Units 〈905〉: Meet the requirements

5 IMPURITIES

Organic Impurities

Procedure

Diluent: Prepare as directed in the Assay.

Solution A: Dissolve 1.2 g of monobasic potassium phosphate in 940 mL of water. Adjust with 5 N potassium hydroxide to a pH of 6.9. Add 60 mL of acetonitrile, and stir. Filter and degas.

Solution B: Dissolve 1.2 g of monobasic potassium phosphate in 700 mL of water. Adjust with 5 N potassium hydroxide to a pH of 6.9. Add 300 mL of acetonitrile and stir. Filter and degas.

Mobile phase: See the gradient table below.

Standard solution: 0.04 mg/mL each of USP Gabapentin RS and USP Gabapentin Related Compound A RS in Diluent Sample solution: Equivalent to 20 mg/mL of gabapentin, from NLT 20 powdered Tablets, in Diluent. [Note—Sonication for about 30 s may be necessary.]

5.1 Chromatographic system

(See Chromatography 〈621〉, System Suitability.)

Mode: LC

Detector: UV 210 nm

Column: 4.6-mm × 25-cm; 5-µm packing L7

Flow rate: 1.5 mL/min

Injection size: 50 µL

5.2 System suitability

Sample: Standard solution

Suitability requirements

Tailing factor: NMT 2.0 for the gabapentin peak

Relative standard deviation: NMT 5.0% for gabapentin and gabapentin related compound A peaks

5.3 Analysis

Samples: Standard solution and Sample solution

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

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

r_U = peak response for gabapentin related compound A from the Sample solution

r_S = peak response for gabapentin related compound A from the Standard solution

C_S = concentration of USP Gabapentin Related Compound A RS in the Standard solution (mg/mL)

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

Calculate the percentage of any other unspecified degradation product relative to the gabapentin content in the portion of Tablets taken:

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

r_U = peak response for each unspecified impurity from the Sample solution

r_S = peak response for gabapentin from the Standard solution

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

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

Acceptance criteria

Gabapentin related compound A: NMT 0.4%

Any individual unspecified impurity: NMT 0.1%

Total impurities: NMT 1.0%

6 ADDITIONAL REQUIREMENTS

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

Labeling: When more than one Dissolution test is given, the labeling states the Dissolution test used only if Test 1 is not used.

USP Reference Standards 〈11〉

USP Gabapentin RS

USP Gabapentin Related Compound A RS

2-Aza-spiro[4.5]decan-3-one.

C₉H₁₅NO      153.22