Tyrosine (tye' roe seen). DEFINITION Tyrosine contains NLT 98.5% and NMT 101.5% of l-tyrosine (C9H11NO3), calculated on the dried basis. IDENTIFICATION ASSAY • Procedure Sample: 180 mg of Tyrosine Blank: Mix 6 mL of formic acid and 50 mL of glacial acetic acid. Titrimetric system (See Titrimetry 541.) Mode: Direct titration Titrant: 0.1 N perchloric acid VS Endpoint detection: Potentiometric Analysis: Dissolve the Sample in 6 mL of formic acid and 50 mL of glacial acetic acid, and titrate with the Titrant. Perform the Blank determination. Calculate the percentage of tyrosine (C9H11NO3) in the Sample taken: Result = {[(VS VB) × N × F]/W} × 100
Acceptance criteria: 98.5%101.5% on the dried basis IMPURITIES • Residue on Ignition 281: NMT 0.4% • Chloride and Sulfate, Chloride 221 Standard solution: 0.20 mL of 0.020 N hydrochloric acid Sample: 0.35 g of Tyrosine. [NoteIf necessary, dissolve the Sample by heating to near boiling and adding 1 mL of nitric acid. ] Acceptance criteria: NMT 0.04% • Chloride and Sulfate, Sulfate 221 Standard solution: 0.50 mL of 0.020 N sulfuric acid Sample: 1.2 g of Tyrosine. [NoteIf necessary, dissolve the Sample by adding 6 mL of diluted hydrochloric acid. ] Acceptance criteria: NMT 0.04% • Iron 241: NMT 30 ppm. [NoteIf necessary, use 2 mL of hydrochloric acid to dissolve the Sample. ] • Heavy Metals, Method I 231: NMT 15 ppm • Related Compounds Diluted ammonia solution: Dilute 16 mL of concentrated ammonia with water to 100 mL. System suitability solution: Dissolve 10 mg of USP l-Tyrosine RS and 10 mg of USP l-Phenylalanine RS in 1 mL of Diluted ammonia solution, and dilute with water to 25.0 mL. Standard solution: In a suitable flask, dissolve a quantity of USP l-Tyrosine RS in 1 mL of Diluted ammonia solution. Dilute with water to volume to obtain a solution of 0.05 mg/mL. [NoteThis solution has a concentration equivalent to 0.5% of that of the Sample solution. ] Sample solution: Transfer 0.1 g of Tyrosine into a 10-mL volumetric flask, add sufficient Diluted ammonia solution to dissolve, and dilute with water to volume. Chromatographic system Mode: TLC Adsorbent: 0.25-mm layer of chromatographic silica gel mixture Application volume: 5 µL Developing solvent system: Isopropyl alcohol and ammonium hydroxide (7:3) Spray reagent: 2 mg/mL of ninhydrin in a mixture of butyl alcohol and 2 N acetic acid (95:5) System suitability Suitability requirements: The chromatogram of the System suitability solution exhibits two clearly separated spots. Analysis Samples: System suitability solution, Standard solution, and Sample solution Dry the plate between 100 and 105 until the ammonia disappears completely. Spray with Spray reagent, and heat between 100 and 105 for 15 min. Examine the plate under white light. Acceptance criteria: Any secondary spot of the Sample solution is not larger or more intense than the principal spot of the Standard solution. Any individual impurity: NMT 0.5% Total impurities: NMT 2.0% SPECIFIC TESTS • Optical Rotation, Specific Rotation 781S Sample solution: 50 mg/mL in 1 N hydrochloric acid Acceptance criteria: 9.8 to 11.2 • Loss on Drying 731: Dry a sample at 105 for 3 h: it loses NMT 0.3% of its weight. ADDITIONAL REQUIREMENTS • Packaging and Storage: Preserve in well-closed containers. Auxiliary Information Please check for your question in the FAQs before contacting USP.
USP35NF30 Page 4976 Pharmacopeial Forum: Volume No. 32(6) Page 1761Chromatographic Column Chromatographic columns text is not derived from, and not part of, USP 35 or NF 30. |