Pentazocine and Acetaminophen Tablets
» Pentazocine and Acetaminophen Tablets contain an amount of Pentazocine Hydrochloride equivalent to not less than 90.0 percent and not more than 110.0 percent of the labeled amount of pentazocine (C19H27NO) and not less than 90.0 percent and not more than 110.0 percent of the labeled amount of acetaminophen (C8H9NO2).
Packaging and storage—
Preserve in tight, light-resistant containers.
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Thin-layer chromatographic identification test 
201
—
201—
Test solution—
Transfer a quantity of finely powdered Tablets, equivalent to about 5 mg of pentazocine and 130 mg of acetaminophen, to a suitable flask, and add 5 mL of a mixture of chloroform and methanol (1:1), shake, and allow the solids to settle. Use the supernatant.
Standard solutions—
Prepare a solution of USP Pentazocine RS in a mixture of chloroform and methanol (1:1) containing 1 mg per mL (Standard solution A). Using the same solvent, prepare a solution of USP Acetaminophen RS containing 26 mg per mL (Standard solution B).
Developing solvent system:
a mixture of ethyl acetate, methanol, and formic acid (90:5:5).
Procedure—
Evaporate the solvents in cool, circulating air. After developing and examining the spots, spray the plate with iodoplatinate reagent prepared by dissolving 300 mg of platinic chloride in 100 mL of water and adding 100 mL of potassium iodide solution (6 in 100): the chromatogram obtained with the Test solution shows two principal spots that correspond in RF values, size, and intensity of color with the spots obtained from Standard solutions A and B.
Uniformity of dosage units 905:
meet the requirements.
905:
meet the requirements.
procedure for content uniformity of pentazocine and acetaminophen—
Solvent—
Prepare a mixture of acetonitrile and 0.035 N sulfuric acid (6:4).
Mobile phase—
Prepare a mixture of 0.005 M monobasic sodium phosphate, tetrahydrofuran, and phosphoric acid (950:50:1). Make adjustments if necessary (see System Suitability under Chromatography 621).
621).
Pentazocine standard stock solution—
Dissolve an accurately weighed quantity of USP Pentazocine RS in Solvent, and dilute quantitatively with Solvent to obtain a solution having a known concentration of about 0.25 mg per mL.
Standard solution—
Transfer an accurately weighed quantity of USP Acetaminophen RS to a suitable volumetric flask, add a sufficient volume of Pentazocine standard stock solution, and mix to dissolve the acetaminophen. Dilute with Mobile phase to volume, and mix to obtain known concentrations of about 0.0125 mg and 0.325 mg of pentazocine and acetaminophen per mL, respectively.
Test solution—
Transfer 1 Tablet to a 100-mL volumetric flask, add 50 mL of Solvent, and sonicate for about 30 minutes. Dilute with Solvent to volume, and mix. Pass a portion of this solution through a paper filter, covering the funnel with a watch glass, and discarding the first few mL of the filtrate. Dilute 5.0 mL of the filtrate with Mobile phase to 100 mL, and pass this solution through a membrane filter having a 0.5-µm or finer porosity.
System suitability solution—
Transfer about 32.5 mg of USP Acetaminophen RS to a 100-mL volumetric flask, dissolve in and dilute with Solvent to volume, and mix. Transfer 1.0 mL of this solution to a 100-mL volumetric flask, add 5.0 mL of Pentazocine standard stock solution, dilute with Mobile phase to volume, and mix.
Chromatographic system (see Chromatography 621)—
The liquid chromatograph is equipped with a 220-nm detector and a 9.4-mm × 10-cm column that contains 5-µm packing L1. The flow rate is about 1.5 mL per minute. Chromatograph the System suitability solution, and record the peak responses as directed for Procedure: the relative retention times are about 0.2 for acetaminophen and 1.0 for pentazocine; the resolution, R, between pentazocine and acetaminophen is not less than 7; and the relative standard deviation for replicate injections is not more than 2.0% for the pentazocine and acetaminophen peaks.
621)—
The liquid chromatograph is equipped with a 220-nm detector and a 9.4-mm × 10-cm column that contains 5-µm packing L1. The flow rate is about 1.5 mL per minute. Chromatograph the System suitability solution, and record the peak responses as directed for Procedure: the relative retention times are about 0.2 for acetaminophen and 1.0 for pentazocine; the resolution, R, between pentazocine and acetaminophen is not less than 7; and the relative standard deviation for replicate injections is not more than 2.0% for the pentazocine and acetaminophen peaks.
Procedure—
Separately inject equal volumes (about 10 µL) of the Standard solution and the Test solution into the liquid chromatograph, and measure the responses for the pentazocine and the acetaminophen peaks. Calculate the quantity, in mg, of pentazocine (C19H27NO) and acetaminophen (C8H9NO2) in the portion of Tablets taken by the formula:
2000C(rU / rS)
in which C is the concentration, in mg per mL, of the appropriate USP Reference Standard in the Standard solution; and rU and rS are the peak responses for the corresponding analyte obtained from the Test solution and the Standard solution, respectively.
Assay for pentazocine—
Mobile phase—
Prepare a mixture of chloroform, methanol, and isopropylamine (96:4:0.2).
Diluent—
Prepare a mixture of methanol and 0.035 N sulfuric acid (1:1).
Standard preparation—
Dissolve an accurately weighed quantity of USP Pentazocine RS in Diluent, and dilute quantitatively with the same solvent to obtain a stock solution having a known concentration of about 0.5 mg per mL. Transfer 10.0 mL of this stock solution to a 125-mL separator. Add 30 mL of water and 5 mL of sodium carbonate solution (1:10), and mix. Extract with 60 mL of chloroform, pass the chloroform layer through filter paper, collecting the filtrate in a 100-mL volumetric flask, dilute with chloroform to volume, and mix.
Assay preparation—
Weigh and finely powder not fewer than 20 Tablets. Transfer an accurately weighed portion of the powder, equivalent to about 25 mg of pentazocine, to a 50-mL glass-stoppered cylinder, add 50.0 mL of Diluent, and shake intermittently for about 15 minutes. Sonicate for about 2 minutes, allow the solids to settle, and transfer 10.0 mL of the supernatant to a 125-mL separator. [note—Save the remainder of the supernatant for use in the Assay for acetaminophen. Minimize the waiting period before this test is performed to prevent significant hydrolysis of acetaminophen to p-aminophenol. ] Add 30 mL of water and 5 mL of sodium carbonate solution (1:10) to the separator, and mix. Extract with 60 mL of chloroform, pass the chloroform layer through filter paper, collecting the filtrate in a 100-mL volumetric flask, dilute with chloroform to volume, and mix.
Chromatographic system (see Chromatography 621)—
The liquid chromatograph is equipped with a 280-nm detector and a 4.6-mm × 25-cm column that contains 10-µm packing L3. 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 1000 theoretical plates; the tailing factor is not more than 3.0; and the relative standard deviation for replicate injections is not more than 2.0%.
621)—
The liquid chromatograph is equipped with a 280-nm detector and a 4.6-mm × 25-cm column that contains 10-µm packing L3. 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 1000 theoretical plates; the tailing factor is not more than 3.0; and the relative standard deviation for replicate injections is not more than 2.0%.
Procedure—
Separately inject equal volumes (about 20 µL) of the Standard preparation and the Assay preparation into the liquid chromatograph, record the chromatograms, and measure the responses for the pentazocine peaks. Calculate the quantity, in mg, of pentazocine (C19H27NO) in the portion of Tablets taken by the formula:
50C(rU / rS)
in which C is the concentration, in mg per mL, of USP Pentazocine RS in the stock solution used to prepare the Standard preparation; and rU and rS are the peak responses obtained from the Assay preparation and the Standard preparation, respectively.
Assay for acetaminophen—
Mobile phase and Diluent—
Proceed as directed in the Assay for pentazocine.
Standard preparation—
[note—Minimize the time between addition of the Diluent and injection of the Assay preparaton to prevent significant hydrolysis of acetaminophen to p-aminophenol.] Transfer about 130 mg of USP Acetaminophen RS, accurately weighed, to a 10-mL volumetric flask, dissolve in and dilute with Diluent to volume, and mix. Transfer 2.0 mL of this solution to a 200-mL volumetric flask, and dilute with ethyl acetate to volume, and mix.
Assay preparation—
Transfer 2.0 mL of the supernatant reserved from the Assay for pentazocine to a 200-mL volumetric flask, dilute immediately (to minimize hydrolysis of acetaminophen to p-aminophenol) with ethyl acetate to volume, and mix.
Chromatographic system (see Chromatography 621)—
The liquid chromatograph is equipped with a 254-nm detector and a 4.6-mm × 25-cm column that contains 10-µm packing L3. The flow rate is about 1.4 mL per minute. Chromatograph the Standard preparation, and record the peak responses as directed for Procedure: the column efficiency is not less than 1000 theoretical plates; the tailing factor is not more than 3.0; and the relative standard deviation for replicate injections is not more than 2.0%.
621)—
The liquid chromatograph is equipped with a 254-nm detector and a 4.6-mm × 25-cm column that contains 10-µm packing L3. The flow rate is about 1.4 mL per minute. Chromatograph the Standard preparation, and record the peak responses as directed for Procedure: the column efficiency is not less than 1000 theoretical plates; the tailing factor is not more than 3.0; and the relative standard deviation for replicate injections is not more than 2.0%.
Procedure—
Separately inject equal volumes (about 10 µL) of the Standard preparation and the Assay preparation into the chromatograph, record the chromatograms, and measure the responses for the acetaminophen peak. Calculate the quantity, in mg, of acetaminophen (C8H9NO2) in the portion of Tablets taken by the formula:
100C(rU / rS)
in which C is the concentration, in mg per mL, of USP Acetaminophen RS in the Standard preparation; 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 | Clydewyn M. Anthony, Ph.D.
Senior Scientific Liaison 1-301-816-8139 |
(SM22010) Monographs - Small Molecules 2 |
| Reference Standards | RS Technical Services 1-301-816-8129 rstech@usp.org |
USP35–NF30 Page 4257
Pharmacopeial Forum: Volume No. 33(6) Page 1200