N-Acetyl-L-Tyrosine CAS 537-55-3 (Ac-Tyr-OH; NALT) Assay 99.0~101.0 Factory

N-Acetyl-L-Tyrosine (Ac-Tyr-OH; NALT) (CAS: 537-55-3) AJI97 Test Method
N-Acetyl-L-Tyrosine, when dried, contains not less than 99.0 percent and not more than 101.0 percent of N-Acetyl-L-Tyrosine (C11H13NO4).
Description: White crystals or crystalline powder, strongly acid taste
Freely soluble in water.
Solubility (H2O, g/100g): 17.5 (20℃), 72.4 (40℃), 158 (60℃)
Identification: Compare the infrared absorption spectrum of the sample with that of the standard by potassium bromide disc method.
Specific Rotation [α]20/D: Dried sample, C=4, H2O
State of Solution (Transmittance): 0.5g in 10ml of H2O, spectrophotometer, 430nm, 10mm cell thickness.
Chloride (Cl): 0.7g, A-1, ref: 0.40ml of 0.01mol/L HCl
Ammonium (NH4): B-1
Sulfate (SO4): 1.2g, (1), ref: 0.50ml of 0.005mol/L H2SO4
Iron (Fe): 0.5g, ref: 1.5ml of Iron Std. (0.01mg/ml)
Heavy Metals (Pb): 2.0g, (3), ref: 2.0ml of Pb Std. (0.01mg/ml)
Arsenic (As2O3): 1.0g, (1), ref: 2.0ml of As2O3 Std.
Loss on Drying: at 105℃ for 3 hours
Residue on Ignition (Sulfated): AJI Test 13
Assay: Dried sample, 300mg, (1), 40ml H2O, (2), 0.1mol/L NaOH, 1ml=22.323mg C11H13NO4
Tyrosine: Liquid chromatography. Operating condition: Detector: UV absorption photometer (214nm); Column: ODS, 4.6mm x 150mm; Column Temperature: Room temperature. Flow rate: 1ml/min; Mobile phase: 0.04mol/L solution of monopotassium phosphate (pH 4.35): Methanol (193:3)
pH: 1.25g in 50ml of H2O
Recommended storage limit and condition: Preseved tight containers at controlled room temperature (2 years).

N-Acetyl-L-Tyrosine (Ac-Tyr-OH; NALT) (CAS: 537-55-3) USP35 Test Method
DEFINITION
N-Acetyltyrosine contains NLT 98.5% and NMT 101.0% of C11H13NO4, as N-Acetyl-L-Tyrosine, calculated on the dried basis.
IDENTIFICATION
A. INFRARED ABSORPTION <197K>
B. OPTICAL ROTATION, Specific Rotation <781S>
Sample solution: 10 mg/mL
Acceptance criteria: NLT +46.0° and NMT +49.0°, determined at 20°
C. The RF value of the principal spot of the Sample solution in the test for Organic Impurities corresponds to that of Standard solution 1.
ASSAY
PROCEDURE
Sample solution: Dissolve about 180 mg of N-Acetyltyrosine, weighed, in 50 mL of carbon dioxide-free water.
Titrimetric system
(See Titrimetry <541>)
Mode: Direct titration
Titrant: 0.1 N sodium hydroxide VS
Endpoint detection: Potentiometric
Equivalency: Each mL of 0.1 N sodium hydroxide VS is equivalent to 22.32 mg of C11H13NO4.
IMPURITIES
Inorganic Impurities
RESIDUEON IGNITION <281>: NMT 0.1%
CHLORIDE AND SULFATE, Chloride <221> NMT 200 ppm. A 0.7-g portion shows no more chloride than corresponds to 0.40 mL of 0.01 N hydrochloric acid.
CHLORIDE AND SULFATE, Sulfate <221> NMT 200 ppm. A 1.2-g portion shows no more sulfate than corresponds to 0.25 mL of 0.020 N sulfuric acid.
IRON <241>: NMT 20ppm
HEAVY METALS, Method I <231>: NMT 10ppm
Organic Impurities
PROCEDURE
Adsorbent: 0.25-mm layer of chromatographic silica gel mixture
Standard stock solution 1: 8 mg/mL of USP N-Acetyl-L-tyrosine RS in a mixture of water, glacial acetic acid, and alcohol (3:3:94)
Standard solution 1: Dilute Standard stock solution 1 with alcohol to obtain a solution having a known concentration of about 0.4 mg/mL
Standard solution 2: 0.8 mg/mL of USP L-Tyrosine RS dissolved in a mixture of glacial acetic acid and water (1:1), and diluted with alcohol
Sample solution: Transfer 0.8 g of N-Acetyltyrosine to a 10-mL volumetric flask, dissolve in 6 mL of a mixture of glacial acetic acid and water (1:1), and dilute with alcohol to volume.
Application volume: 5 µL
Developing solvent system: A mixture of ammonia and 2-propanol (3:7)
Spray reagent: Dissolve 0.2 g of ninhydrin in 100 mL of a mixture of butanol and 2 N acetic acid (95:5).
System suitability
Suitability requirements: The chromatogram of the System suitability solution exhibits two clearly separated spots.
Analysis: Proceed as directed for Chromatography <621> Thin-Layer Chromatography. After air-drying the plate, repeat the development process. After air-drying a second time, spray with Spray reagent, and heat between 100° and 105° for about 15 min.
Acceptance criteria: Any secondary spot of the Sample solution is not larger or more intense than the principal spot of the Standard solution1, except for the spot corresponding to tyrosine, which is not larger or more intense than the principal spot from Standard solution 2.
Individual impurities: NMT 0.5%
Limit of tyrosine: NMT 1.0%
SPECIFIC TESTS
LOSSON DRYING <731>: Dry a sample at 105℃ for 3 h: it loses NMT 0.1% of its weight.
ADDITIONAL REQUIREMENTS
PACKAGING AND STORAGE: Preserve in well-closed containers, and store at controlled room temperature.
USP REFERENCE STANDARDS <11>
USP N-Acetyl-L-tyrosine RS
USP L-Tyrosine RS