Gabapentin Tablets
» Gabapentin Tablets 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.
Identification
A:
Infrared Absorption 197K.
Test specimen
Grind at least 20 Tablets to a fine powder. Use an amount of powder, equivalent to about 2 mg of gabapentin, and about 200 mg of dry 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
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:
45 minutes.
Determine the amount of gabapentin (C9H17NO2) dissolved by 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 final solution having a known concentration of about 1.1 mg per mL.
Working standard solutions
Dilute aliquots of the Standard stock solution with Medium to obtain solutions having the following concentrations: 110 µg per mL for Tablets labeled to contain 100 mg; 330 µg per mL for Tablets labeled to contain 300 mg; 440 µg per mL for Tablets labeled to contain 400 mg; 660 µg per mL for Tablets labeled to contain 600 mg; and 880 µg per mL for Tablets labeled to contain 800 mg.
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 solutions: the column efficiency is not less than 5000 theoretical plates; the tailing factor is not more than 2.0; and the relative standard deviation for replicate injections is not more than 3%.
Procedure
Separately inject equal volumes (about 100 µL for the Tablets labeled to contain 100, 300, or 400 mg; and about 50 µL for Tablets labeled to contain 600 or 800 mg) 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 Tablet label claim, in mg.
Tolerances
Not less than 80% (Q) of the labeled amount of gabapentin (C9H17NO2) is dissolved in 45 minutes.
Uniformity of dosage units 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).
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
Weigh and finely powder not fewer than 20 Tablets. 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.
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 Tablets 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 Tablets 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 the 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 degradation product 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).
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
Weigh and finely powder not fewer than 20 Tablets. 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%.
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 Tablets 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.
Chromatographic Column
USP32NF27 Page 2465
Pharmacopeial Forum: Volume No. 34(4) Page 934
Chromatographic columns text is not derived from, and not part of, USP 32 or NF 27.
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