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Acetylcysteine contains NLT 98.0% and NMT 102.0% of C5H9NO3S, calculated on the dried basis.
Mobile phase: 6.8 g/L of monobasic potassium phosphate. Adjust with phosphoric acid to a pH of 3.0.
Sodium metabisulfite solution: 0.5 mg/mL of sodium metabisulfite in water, freshly prepared
Internal standard solution: 5 mg/mL of USP l-Phenylalanine RS in Sodium metabisulfite solution
Standard stock solution: 10 mg/mL of USP Acetylcysteine RS in Sodium metabisulfite solution
Standard solution: 0.5 mg/mL of USP Acetylcysteine RS and 0.25 mg/mL of USP l-Phenylalanine RS in Sodium metabisulfite solution from Standard stock solution and Internal standard solution
Sample stock solution: 10 mg/mL of Acetylcysteine in Sodium metabisulfite solution
Sample solution: 0.5 mg/mL of Acetylcysteine and 0.25 mg/mL of USP l-Phenylalanine RS in Sodium metabisulfite solution from Sample stock solution and Internal standard solution
Detector: UV 214 nm
Column: 3.9-mm × 30-cm; packing L1
Flow rate: 1.5 mL/min
Injection size: 5 µL
Sample: Standard solution
[NoteThe relative retention times for acetylcysteine and l-phenylalanine are about 0.5 and 1.0, respectively. ]
Resolution: NLT 6 between acetylcysteine and l-phenylalanine
Relative standard deviation: NMT 2.0%
Samples: Standard solution and Sample solution
Calculate the percentage of acetylcysteine (C5H9NO3S) in the portion of Acetylcysteine taken:
Result = (RU/RS) × (CS/CU) × 100
Acceptance criteria: 98.0%102.0% on the dried basis
• Residue on Ignition 281: NMT 0.5%
• Heavy Metals, Method II 231
[CautionExercise care because explosion may occur. ]
Analysis: In a dropwise manner, wet the sample with 2 mL of nitric acid, and proceed as directed for the Test preparation.
Acceptance criteria: NMT 10 ppm
• Optical Rotation, Specific Rotation 781S
Buffer: Mix 29.5 mL of 1 N sodium hydroxide, 50 mL of 1 M monobasic potassium phosphate, and sufficient water to make 100 mL. Adjust to a pH of 7.0 ± 0.1 by adding more of either solution, as necessary.
Sample solution: In a 25-mL volumetric flask, mix 1.25 g with 1 mL of edetate disodium solution (1 in 100), add 7.5 mL of sodium hydroxide solution (1 in 25), and mix to dissolve. Dilute with Buffer to volume.
Acceptance criteria: +21 to +27
• pH 791: 2.02.8 in a solution (1 in 100)
• Loss on Drying 731: Dry a sample at a pressure of about 50 mm of mercury at 70 for 4 h: it loses NMT 1.0% of its weight.
• Packaging and Storage: Preserve in tight containers, and store at controlled room temperature.
• USP Reference Standards 11
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USP35NF30 Page 2069Pharmacopeial Forum: Volume No. 31(3) Page 726