Tromethamine
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This article is compiled based on the United States Pharmacopeia (USP) – 2025 Edition
Issued and maintained by the United States Pharmacopeial Convention (USP)
C4H11NO3 121.14
1,3-Propanediol, 2-amino-2-(hydroxymethyl)-;
2-Amino-2-(hydroxymethyl)-1,3-propanediol CAS RN: 77-86-1.
1 DEFINITION
Tromethamine contains NLT 99.0% and NMT 101.0% of tromethamine (C₂H, NO), calculated on the dried basis.
2 IDENTIFICATION
Change to read:
A. SPECTROSCOPIC IDENTIFICATION TESTS (197), Infrared Spectroscopy: 197M
B.
Sample solution: 1 in 5
Analysis: Το 4.5 mL of a saturated solution of salicylaldehyde add 0.5 mL of glacial acetic acid, and mix. Add 4.0 mL of the Sample solution, and mix.
Acceptance criteria: A yellow color is produced.
C.
Sample solution: 1 in 5
Analysis: To 0.5 mL of a solution (4 in 10) of ceric ammonium nitrate in 2 N nitric acid add 3 mL of water and 0.5 mL of the Sample solution, and mix.
Acceptance criteria: The color changes from light yellow to orange.
3 ASSAY
PROCEDURE
Sample: 250 mg
Analysis: Dissolve the Sample in 100 mL of water, add bromocresol purple TS, and titrate with 0.1 N hydrochloric acid VS to a yellow endpoint.
Each mL of 0.1 N hydrochloric acid is equivalent to 12.11 mg of tromethamine (CH, NO₂).
Acceptance criteria: 99.0%-101.0% on the dried basis
4 IMPURITIES
RESIDUE ON IGNITION (281): NMT 0.1%
5 SPECIFIC TESTS
MELTING RANGE OR TEMPERATURE (741): 168-172°
PH (791)
Sample solution: 1 in 20
Acceptance criteria: 10.0-11.5
LOSS ON DRYING (731).
Analysis: Dry at 105° for 3 h.
Acceptance criteria: NMT 1.0%
6 ADDITIONAL REQUIREMENTS
PACKAGING AND STORAGE: Preserve in tight containers.
USP Reference Standards 〈11〉
USP Tromethamine RS
