Gabapentin Capsules
» Gabapentin Capsules contain not less than 90.0 percent and not more than 110.0 percent of the labeled amount of gabapentin (C9H17NO2).
Packaging and storage—
Preserve in well-closed containers. Store at controlled room temperature.
USP Reference standards 
11
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11—
USP Gabapentin RS 
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USP Gabapentin Related Compound A RS
2-Aza-spiro[4.5]decan-3-one.
C9H15NO 153.22
2-Aza-spiro[4.5]decan-3-one.
C9H15NO 153.22
Identification—
A:
Infrared Absorption 197K.
197K.
Test specimen—
Empty the contents of not fewer than 10 Capsules, and grind to a fine powder. Use an amount of the powder, equivalent to 2 mg of gabapentin, and 200 mg of potassium bromide.
B:
The retention time of the major peak in the chromatogram of the Assay preparation corresponds to that in the chromatogram of the Standard preparation, as obtained in the Assay.
Dissolution 711—
711—
Medium:
0.06 N hydrochloric acid (prepared by adding 51 mL of hydrochloric acid to 10 L of water); 900 mL.
Apparatus 2:
50 rpm.
Time:
20 minutes.
Determine the amount of gabapentin (C9H17NO2) dissolved by employing the following method.
Mobile phase—
Proceed as directed in the Assay.
Standard stock solution—
Dissolve an accurately weighed quantity of USP Gabapentin RS in the Medium to obtain a solution having a known concentration of about 1.1 mg per mL.
Working standard solution—
for capsules labeled to contain 100 mg—
Transfer 10.0 mL of the Standard stock solution to a 100-mL volumetric flask, and dilute with Medium to volume.
for capsules labeled to contain 300 mg—
Transfer 30.0 mL of Standard stock solution to a 100-mL volumetric flask, and dilute with Medium to volume.
for capsules labeled to contain 400 mg—
Transfer 20.0 mL of the Standard stock solution to a 50-mL volumetric flask, and dilute with Medium to volume.
Test solution—
Pass a portion of the solution under test through a suitable 0.45-µm filter.
Chromatographic system (see Chromatography 621)—
Proceed as directed in the Assay, except to use the Working standard solution.
621)—
Proceed as directed in the Assay, except to use the Working standard solution.
Procedure—
Separately inject equal volumes (about 100 µL) of the appropriate Working standard solution and the Test solution into the chromatograph, record the chromatograms, and measure the peak responses. Calculate the amount of gabapentin (C9H17NO2) dissolved by the formula:
in which rU and rS are the peak responses for the Working standard solution and the Test solution, respectively; CS is the concentration, in mg per mL, of the Working standard solution; 900 is the volume, in mL, of Medium; 100 is the conversion factor to percentage; and L is the Capsule label claim, in mg.
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Tolerances—
Not less than 80% (Q) of the labeled amount of gabapentin (C9H17NO2) is dissolved in 20 minutes.
Uniformity of dosage units 905:
meet the requirements.
905:
meet the requirements.
Related compounds—
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—
Use variable mixtures of Solution A and Solution B as directed for Chromatographic system. Make adjustments if necessary (see System Suitability under Chromatography 621).
621).
Standard solution—
Dissolve accurately weighed quantities of USP Gabapentin RS and USP Gabapentin Related Compound A RS in Diluent to obtain a solution having a known concentration of about 0.04 mg of each per mL.
Test solution—
Remove and weigh the contents of not fewer than 20 Capsules. Transfer an accurately weighed portion of the powder, equivalent to about 500 mg of gabapentin, to a suitable volumetric flask, and dissolve the contents in Diluent with sonication, if necessary, for about 30 seconds. Dilute with Diluent to volume, and mix to obtain a final solution having a known concentration of about 20 mg per mL, based on the label claim.
Chromatographic system (see Chromatography 621)—
The liquid chromatograph is equipped with a 210-nm detector and a 4.6-mm × 25-cm column that contains 5-µm packing L7. The flow rate is about 1.5 mL per minute. The chromatograph is programmed as follows.
Chromatograph the Standard solution, and record the peak responses as directed for Procedure: the tailing factor for the gabapentin peak is not more than 2.0; and the relative standard deviation for replicate injections for both gabapentin and gabapentin related compound A is not more than 5.0%.
621)—
The liquid chromatograph is equipped with a 210-nm detector and a 4.6-mm × 25-cm column that contains 5-µm packing L7. The flow rate is about 1.5 mL per minute. The chromatograph is programmed as follows.
| Time (minutes) |
Solution A (%) | Solution B (%) | Elution |
|---|---|---|---|
| 0.0–4.0 | 100 | 0 | isocratic |
| 4.0–45.0 | 100®0 | 0®100 | linear gradient |
| 45.0–45.1 | 0®100 | 100®0 | linear gradient |
| 45.1–50.0 | 100 | 0 | re-equilibration |
Procedure—
Separately inject a volume (about 50 µL) of the Standard solution and the Test solution into the chromatograph, record the chromatograms, and measure the peak responses. Calculate the percentage of gabapentin related compound A in the portion of Capsules taken by the formula:
100(CS / CT)(rU / rS)
in which CS is the concentration, in mg per mL, of USP Gabapentin Related Compound A RS in the Standard solution; CT is the concentration, in mg per mL, of gabapentin in the Test solution, based on the label claim; and rU and rS are the individual peak responses for gabapentin related compound A obtained from the Test solution and Standard solution, respectively: not more than 0.4% of gabapentin related compound A is found. Calculate the percentage of any other unspecified degradation product relative to gabapentin content in the portion of Capsules taken using the formula:
100(CS / CT)(ri / rS)
in which CS is the concentration, in mg per mL, of USP Gabapentin RS in the Standard solution; CT is the concentration, in mg per mL, of gabapentin in the Test solution, based on label claim; ri is the response for each unspecified impurity in the Test solution; and rS is the peak response for gabapentin in the Standard solution: not more than 0.1% of any individual unspecified impurity is found, and not more than 1.0% of total impurities is found.
Assay—
Diluent—
Dissolve 1.2 g of monobasic potassium phosphate in 1 L of 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. Make adjustments if necessary (see System Suitability under Chromatography 621).
621).
Standard preparation—
Dissolve an accurately weighed quantity of USP Gabapentin RS in Diluent, and dilute quantitatively, and stepwise if necessary, with Diluent to obtain a solution having a known concentration of about 4.0 mg per mL.
Assay preparation—
Remove and weigh the contents of not fewer than 20 Capsules. Transfer an accurately weighed portion of the powder, equivalent to about 100 mg of gabapentin, to a suitable volumetric flask, and dissolve the contents in Diluent with sonication, if necessary, for about 60 seconds. Dilute with Diluent to volume, and mix to obtain a final solution having a known concentration of about 4.0 mg per mL.
Chromatographic system (see Chromatography 621)
—The liquid chromatograph is equipped with a 210-nm detector and a 4.6-mm × 25-cm column that contains 5-µm packing L7. The flow rate is about 1.2 mL per minute. Chromatograph the Standard preparation, and record the peak responses as directed for Procedure: the column efficiency is not less than 7,000 theoretical plates; the tailing factor is not more than 2.0; and the relative standard deviation for replicate injections is not more than 2.0%.
621)
—The liquid chromatograph is equipped with a 210-nm detector and a 4.6-mm × 25-cm column that contains 5-µm packing L7. The flow rate is about 1.2 mL per minute. Chromatograph the Standard preparation, and record the peak responses as directed for Procedure: the column efficiency is not less than 7,000 theoretical plates; the tailing factor is not more than 2.0; and the relative standard deviation for replicate injections is not more than 2.0%.
Procedure—
Separately inject equal volumes (about 50 µL) of the Standard preparation and the Assay preparation into the chromatograph, record the chromatograms, and measure the responses for the gabapentin peak. Calculate the percentage of the labeled amount of gabapentin (C9H17NO2) in the portion of Capsules taken by the formula:
100(CS / CU)(rU / rS)
in which CS is the concentration, in mg per mL, of USP Gabapentin RS in the Standard preparation; CU is the concentration, in mg per mL, of gabapentin in the Assay preparation, based on the label claim; and rU and rS are the peak responses obtained from the Assay preparation and the Standard preparation, respectively.
Auxiliary Information—
Please check for your question in the FAQs before contacting USP.
| Topic/Question | Contact | Expert Committee |
|---|---|---|
| Monograph | Ravi Ravichandran, Ph.D.
Principal Scientific Liaison 1-301-816-8330 |
(SM42010) Monographs - Small Molecules 4 |
| Reference Standards | RS Technical Services 1-301-816-8129 rstech@usp.org |
|
| 711 |
Margareth R.C. Marques, Ph.D.
Senior Scientific Liaison 1-301-816-8106 |
(GCDF2010) General Chapters - Dosage Forms |
USP35–NF30 Page 3297
Pharmacopeial Forum: Volume No. 32(6) Page 1693