Tranexamic Acid
(tran'' ex am' ik as' id).
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C8H15NO2 157.2
trans-4-(Aminomethyl)cyclohexanecarboxylic acid;    
Cyclohexanecarboxylic acid, 4-(aminomethyl)-, trans     [1197-18-8].
Tranexamic Acid contains NLT 99.0% and NMT 101.0% of C8H15NO2, calculated on the dried basis.
•  Procedure
Sample solution:  140 mg of Tranexamic Acid in 20 mL of glacial acetic acid
Titrimetric system 
Mode:  Direct titration
Titrant:  0.1 N perchloric acid VS
Endpoint detection:  Potentiometric
Sample:  Sample solution
Titrate with 0.1 N perchloric acid VS, determining the endpoint potentiometrically. Carry out a blank titration.
Each mL of 0.1 N perchloric acid is equivalent to 15.72 mg of C8H15NO2.
Acceptance criteria:  99.0%–101.0% on the dried basis
Inorganic Impurities 
•  Residue on Ignition 281: NMT 0.1%; 1-g sample is used
•  Heavy Metals, Method II 231: NMT 10 ppm
•  Chloride and Sulfate, Chloride 221: A 0.51-g portion shows no more chloride than corresponds to 0.1 mL of 0.020 N hydrochloric acid (0.014%).
Organic Impurities 
•  Procedure
Mobile phase:  Dissolve 11.0 g of anhydrous monobasic sodium phosphate in 500 mL of water, and add 5 mL of triethylamine, followed by 1.4 g of sodium lauryl sulfate. Adjust with diluted phosphoric acid (10% w/w) to a pH of 2.5, and dilute with water to 600 mL. Mix this solution with 400 mL of methanol.
System suitability solution:  0.2 mg/mL of USP Tranexamic Acid RS and 0.002 mg/mL of USP Tranexamic Acid Related Compound C RS in water
Standard solution:  50 µg/mL of USP Tranexamic Acid RS in water
Sample solution:  10 mg/mL of Tranexamic Acid in water
Chromatographic system 
Mode:  LC
Detector:  UV 220 nm
Column:  4.6-mm × 25-cm; 5-µm packing L1
Flow rate:  1 mL/min
Injection size:  20 µL
Run time:  3 times the retention time of tranexamic acid
System suitability 
Sample:  System suitability solution
Suitability requirements 
Resolution:  NLT 2.0 between tranexamic acid and 0.002 mg/mL of tranexamic acid related compound C
Samples:  Standard solution and Sample solution
Calculate the percentage of each individual impurity in the portion of Tranexamic Acid taken:
Result = (rU/rS) × (CS/CU) × (0.1F)
rU== peak response for each impurity from the Sample solution
rS== peak response for tranexamic acid from the Standard solution
CS== concentration of USP Tranexamic Acid RS in the Standard solution (µg/mL)
CU== concentration of Tranexamic Acid in the Sample solution (mg/mL)
F== relative response factor (see Impurity Table 1)
Acceptance criteria 
Individual impurities:  See Impurity Table 1.
Total impurities:  NMT 0.2%
[Note—Disregard any peak less than 0.025%. ]
Impurity Table 1
Name Relative
NMT (%)
Tranexamic acid related compound Aa 2.1 1 0.1
Tranexamic acid related compound Bb 1.5 1.2 0.2
Tranexamic acid related compound Cc 1.1 0.005 0.1
Tranexamic Acid 1.0 1.0
Tranexamic acid related compound Dd 1.3 0.006 0.1
a  trans,trans-4,4¢-(Iminodimethylene)di(cyclohexanecarboxylic)acid.
b  cis-4-(Aminomethyl)cyclohexanecarboxylic acid.
c  (RS)-4-(Aminomethyl) cyclohex-1-enecarbocylic acid.
d  4-Aminomethyl benzoic acid.
•  Loss on Drying 731: Dry 1.00 g at 105 under vacuum for 2 h. It loses NMT 0.5% of its weight.
•  Packaging and Storage: Preserve in tight containers, and store at a temperature not exceeding 30.
•  USP Reference Standards 11
USP Tranexamic Acid RS Click to View Structure
USP Tranexamic Acid Related Compound C RS
(RS)-4-(Aminomethyl)cyclohex-1-enecarbocylic acid.
    C8H13NO2        155
Auxiliary Information— Please check for your question in the FAQs before contacting USP.
Topic/Question Contact Expert Committee
Monograph Sujatha Ramakrishna, Ph.D.
Senior Scientific Liaison
(SM22010) Monographs - Small Molecules 2
Reference Standards RS Technical Services
USP35–NF30 Page 4911
Pharmacopeial Forum: Volume No. 34(6) Page 1484