Acetaminophen and Tramadol Hydrochloride Tablets
DEFINITION
Acetaminophen and Tramadol Hydrochloride Tablets contain NLT 90.0% and NMT 110.0% of the labeled amount of acetaminophen (C8H9NO2) and tramadol hydrochloride (C16H25NO2·HCl).
IDENTIFICATION
•  The retention time of the major peaks in the Tramadol sample solution and the Acetaminophen sample solution corresponds to those of the Standard solution, as obtained in the Assay.
ASSAY
•  Procedure
Mobile phase:  Tetrahydrofuran, triethylamine, water, and trifluoroacetic acid (8:0.1:92:0.1). [Note—The apparent pH of the final solvent mixture should be between 2.2 and 2.4. ]
Diluent:  Methanol and water (1:9)
Standard solution:  0.065 mg/mL of USP Acetaminophen RS and 0.075 mg/mL of USP Tramadol Hydrochloride RS in Diluent. [Note—Sonication may be used to aid dissolution. ]
Sample stock solution:  Weigh NLT 20 Tablets, and determine the average Tablet weight. Grind the Tablets into a fine powder, and transfer an amount equivalent to one Tablet to a 50-mL volumetric flask. Add 30 mL of Diluent with continuous shaking to disperse the powder. Sonicate for 15 min with intermittent shaking, and shake the flask on a mechanical shaker for 30 min. Dilute with Diluent to volume, and mix well. Centrifuge the suspension, and use the supernatant for subsequent dilutions.
Tramadol sample solution:  75 µg/mL of tramadol hydrochloride in Diluent from the Sample stock solution
Acetaminophen sample solution:  65 µg/mL of acetaminophen in Diluent from the Sample stock solution
Chromatographic system 
Mode:  LC
Detector:  216 nm for tramadol hydrochloride and 249 nm for acetaminophen
Column:  4.6-mm × 15-cm; 5-µm packing L11
Column temperature:  50
Flow rate:  1.0 mL/min
Injection size:  20 µL
Run time:  Four times the retention time of acetaminophen
System suitability 
Sample:  Standard solution
Suitability requirements 
Resolution:  NLT 10.0 between acetaminophen and tramadol hydrochloride
Column efficiency:  NLT 2000 theoretical plates for each analyte
Tailing factor:  NMT 2.0 for each analyte
Relative standard deviation:  NMT 2.0% for each analyte
Analysis 
Samples:  Standard solution, Tramadol sample solution, and Acetaminophen sample solution
Calculate the percentage of the labeled amount of tramadol hydrochloride (Cl6H25NO2·HCl) in the portion of Tablets taken:
Result = (rU/rS) × (CS/CU) × 100
rU== peak response from the Tramadol sample solution
rS== peak response from the Standard solution
CS== concentration of USP Tramadol Hydrochloride RS in the Standard solution (mg/mL)
CU== nominal concentration of tramadol hydrochloride in the Tramadol sample solution (mg/mL)
Calculate the percentage of the labeled amount of acetaminophen (C8H9NO2) in the portion of Tablets taken:
Result = (rU/rS) × (CS/CU) × 100
rU== peak response from the Acetaminophen sample solution
rS== peak response from the Standard solution
CS== concentration of USP Acetaminophen RS in the Standard solution (mg/mL)
CU== nominal concentration of acetaminophen in the Acetaminophen sample solution (mg/mL)
Acceptance criteria:  NLT 90.0%–110.0%
PERFORMANCE TESTS
•  Dissolution 711
Test 1 
Medium:  0.1 N hydrochloric acid; 900 mL
Apparatus 2:  50 rpm
Time:  30 min
Standard solution:  0.36 mg/mL of USP Acetaminophen RS and 0.04 mg/mL of USP Tramadol Hydrochloride RS in Medium
Sample solution:  Pass a portion of the solution under test through a suitable filter of 0.45-µm pore size.
Buffer solution:  6.8 mg/mL of monobasic potassium phosphate in water. Adjust with phosphoric acid to a pH of 2.50.
Mobile phase:  Acetonitrile and Buffer solution (1:4)
Chromatographic system 
Mode:  LC
Detector:  UV 272 nm
Column:  4.6-mm × 15-cm; 5-µm packing L7
Column temperature:  25
Flow rate:  1.0 mL/min
Injection size:  25 µL
System suitability 
Sample:  Standard solution
[Note—The relative retention times for acetaminophen and tramadol hydrochloride are about 0.5 and 1.0, respectively. ]
Suitability requirements 
Resolution:  NLT 5.0 between the peaks for acetaminophen and tramadol hydrochloride
Relative standard deviation:  NMT 2.0% for both the acetaminophen and tramadol hydrochloride peaks
Analysis 
Samples:  Standard solution and Sample solution
Record the chromatograms for two times the retention time of tramadol hydrochloride. Calculate the percentage of the labeled amount of acetaminophen (C8H9NO2) and tramadol hydrochloride (Cl6H25NO2·HCl) dissolved:
Result = (rU × CS × V × 100)/(rS × L)
rU== peak response of acetaminophen or tramadol hydrochloride from the Sample solution
CS== concentration of USP Acetaminophen RS or USP Tramadol Hydrochloride RS in the Standard solution (mg/mL)
V== volume of Medium, 900 mL
rS== peak response of acetaminophen or tramadol hydrochloride from the Standard solution
L== label claim for acetaminophen or tramadol hydrochloride (mg/Tablet)
Tolerances:  NLT 80% (Q) of the labeled amounts of acetaminophen and tramadol hydrochloride is dissolved.
Test 2:  If the product complies with this test, the labeling indicates that it meets USP Dissolution Test 2.
Medium:  0.1 N hydrochloric acid; 900 mL
Apparatus 2:  50 rpm
Time:  20 min
Standard solution, Sample solution, Buffer solution, Mobile phase, Chromatographic system, and Analysis:  Proceed as directed in Dissolution Test 1.
Tolerances:  NLT 80% (Q) of the labeled amounts of acetaminophen and tramadol hydrochloride is dissolved.
•  Uniformity of Dosage Units 905: Meet the requirements
OTHER COMPONENTS
•  Limit of p-Aminophenol
[Note—All Standards, the Sample solution, and the Blank solution must be mixed with the Basic ferricyanide solution and analyzed as soon as possible after a 30-min waiting period. ]
Diluent:  Methanol and water (1:1)
Basic ferricyanide solution:  Dissolve 1 g of sodium ferricyanide and 1 g of anhydrous sodium carbonate in 100 mL of water.
Standard solution:  Dissolve USP p-Aminophenol RS in Diluent to obtain a solution having a known concentration of 0.05 mg/mL. Sonicate if necessary to dissolve. Transfer 5 mL of the resulting solution to a 100-mL volumetric flask, and add 50 mL of Diluent and 5 mL of Basic ferricyanide solution. Dilute with Diluent to volume, and mix. Let stand for 30 min. Pass the solution through a nylon membrane filter of 0.45-µm pore size, and use the filtrate.
Sample solution:  Weigh NLT 20 Tablets. Grind the Tablets into a fine powder. Accurately transfer an amount of powder, equivalent to about 5 g of acetaminophen based on the label claim, to a 100-mL volumetric flask. Add 50 mL of Diluent, and sonicate for 15 min with intermittent shaking, followed by mechanical shaking for 30 min. Add 6 mL of Basic ferricyanide solution. Dilute with Diluent to volume, mix, and let stand for 30 min. Centrifuge a portion of the solution, and pass the clear supernatant through a nylon membrane filter of 0.45-µm pore size, and use the filtrate for analysis.
Blank solution:  Add 50 mL of Diluent to a 100-mL volumetric flask. Add 5 mL of Basic ferricyanide solution. Dilute with Diluent to volume, and let stand for 30 min. Pass a portion of the solution through a nylon membrane filter of 0.45-µm pore size, and use the filtrate for analysis.
Instrumental conditions 
Mode:  UV-Vis
Analytical wavelength:  710 nm
Cell:  1 cm
System suitability 
Sample:  Standard solution
Suitability requirements 
Relative standard deviation:  NMT 6.0%
[Note—The percent difference between the initial and final absorbance readings of the Standard solution differs by NMT 10%. ]
Analysis 
Samples:  Standard solution and Sample solution
Calculate the percentage of p-aminophenol in the portion of Tablets taken:
Result = (rU/rS) × (CS/CU) × 100
rU== absorbance from the Sample solution
rS== absorbance from the Standard solution
CS== concentration of USP p-Aminophenol RS in the Standard solution (mg/mL)
CU== nominal concentration of acetaminophen in the Sample solution (mg/mL)
Acceptance criteria:  NMT 0.01%
IMPURITIES
•  Organic Impurities
Mobile phase, Diluent, and Sample stock solution:  Proceed as directed in the Assay.
Standard solution:  0.75 µg/mL each of USP Tramadol Hydrochloride RS and USP Tramadol Related Compound A RS in Diluent
Sample solution:  Pass a suitable volume of Sample stock solution through a nylon membrane filter of 0.45-µm pore size. Use the filtrate after discarding the first 4 mL of filtrate.
Chromatographic system 
Mode:  LC
Detector:  216 nm
Column:  4.6-mm × 15-cm; 5-µm packing L11
Column temperature:  50
Flow rate:  1.0 mL/min
Injection size:  30 µL
System suitability 
Sample:  Standard solution
Suitability requirements 
Resolution:  NLT 2.0 between tramadol related compound A and tramadol hydrochloride
Column efficiency:  NLT 2000 theoretical plates for tramadol hydrochloride
Relative standard deviation:  NMT 6.0% for tramadol hydrochloride
Analysis 
Samples:  Diluent, Standard solution, and Sample solution
[Note—Disregard the peaks due to the Diluent. ]
Calculate the percentage of each known and unknown impurity in the portion of Tablets taken:
Result = (rU/rS) × (CS/CU) × 100
rU== peak response of each individual impurity from the Sample solution
rS== peak response of tramadol hydrochloride from the Standard solution
CS== concentration of USP Tramadol Hydrochloride RS in the Standard solution (µg/mL)
CU== nominal concentration of tramadol hydrochloride in the Sample solution (µg/mL)
Acceptance criteria:  See Table 1.
Table 1
Name Relative
Retention
Time
Acceptance
Criteria,
NMT (%)
O-Desmethyl-tramadola 0.60 0.2
Tramadol related compound Ab 0.80 0.2
Tramadol hydrochloride 1.0
Acetaminophen 0.38
Any other individual unspecified degradation product 0.2
Total impurities 0.8
a  3-{(1RS,2RS)-2-[(Dimethylamino)methyl]-1-hydroxycyclohexyl}phenol.
b  (RS,SR-1-(3-Methoxyphenyl)-2-(dimethylaminomethyl)cyclohexanol hydrochloride.
ADDITIONAL REQUIREMENTS
•  Packaging and Storage: Preserve in tight 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 Acetaminophen RS Click to View Structure
4¢-Hydroxyacetanilide.
    C8H9NO2        151.16
USP p-Aminophenol RS
4-Amino-1-hydroxybenzene.
    C6H7NO        109.13
USP Tramadol Hydrochloride RS Click to View Structure
(±)-cis-2-[(Dimethylamino)methyl]-1-(m-methoxyphenyl)cyclohexanol hydrochloride.
    C16H25NO2·HCl        299.84
USP Tramadol Related Compound A RS
RS,SR-1-(3-Methoxyphenyl)-2-(dimethylaminomethyl)cyclohexanol hydrochloride.
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
711 Margareth R.C. Marques, Ph.D.
Senior Scientific Liaison
1-301-816-8106
(GCDF2010) General Chapters - Dosage Forms
Reference Standards RS Technical Services
1-301-816-8129
rstech@usp.org
USP35–NF30 Page 2060
Pharmacopeial Forum: Volume No. 35(1) Page 56