Methylsulfonylmethane contains NLT 98.0% and NMT 102.0% of methylsulfonylmethane (C2H6O2S), calculated on the anhydrous basis. The chromatographic purity is NLT 99.8%.
• B. The retention time of the major peak of the Sample solution corresponds to that of the Standard solution, as obtained in the Assay.
Diluent: Transfer 950 mL of methanol to a 1-L volumetric flask. Add 0.60 mL of di(ethylene glycol) methyl ether, and dilute with methanol to volume.
Standard solution: 0.4 mg/mL of USP Methylsulfonylmethane RS in Diluent. Sonicate at 50 for 1 min, and allow to cool to room temperature.
Sample solution: 0.4 mg/mL of Methylsulfonylmethane in Diluent. Sonicate at 50 for 1 min, and allow to cool to room temperature.
Detector: Flame ionization
Column: 0.53-mm × 30-m capillary column coated with a 5-µm phase G2
Carrier gas: Helium
Flow rate: 5 mL/min
Split ratio: 2:1
Injection size: 1 µL
Sample: Standard solution
Relative standard deviation: NMT 2.0% for the peak response ratio of methylsulfonylmethane to di(ethylene glycol) methyl ether from replicate injections
Samples: Standard solution and Sample solution
Calculate the percentage of methylsulfonylmethane (C2H6O2S) in the portion of Methylsulfonylmethane taken:
Result = (RU/RS) × (CS/CU) × 100
Acceptance criteria: 98.0%102.0% on the anhydrous basis
• Heavy Metals, Method I 231: NMT 3 µg/g
• Chromatographic Purity and Limit of Dimethyl Sulfoxide
Standard stock solution: 1.0 mg/mL of USP Dimethyl Sulfoxide RS in methanol
Sensitivity check solution: 2.0 µg/mL from the Standard stock solution in methanol
System suitability solution: 0.1 mg/mL of USP Dimethyl Sulfoxide RS and 0.4 mg/mL of USP Methylsulfonylmethane RS in methanol. In a 50-mL volumetric flask dissolve 20 mg of USP Methylsulfonylmethane RS in 5 mL of the Standard stock solution, and dilute with methanol to volume.
Sample solution: 2 mg/mL of Methylsulfonylmethane in methanol. Sonicate at 50 for 1 min, and allow to cool to room temperature.
Chromatographic system: Proceed as directed in the Assay.
Samples: Sensitivity check solution and System suitability solution
Signal-to-noise ratio: NLT 10 for dimethyl sulfoxide peak, Sensitivity check solution
Resolution: NLT 2.0 between dimethyl sulfoxide and methylsulfonylmethane, System suitability solution
Sample: Sample solution
Calculate the percentage of each impurity in the portion of Methylsulfonylmethane taken:
Result = (rU/rT) × 100
Individual impurities: NMT 0.1% of dimethyl sulfoxide; NMT 0.05% of any other individual impurity
Total impurities: NMT 0.2% for all impurities, including dimethyl sulfoxide
• Melting Range or Temperature 741: 108.5110.5
• Microbial Enumeration Tests 2021: The total aerobic microbial count is NMT 103 cfu/g or mL, and the total combined molds and yeasts count is NMT 102 cfu/g or mL.
• Absence of Specified Microorganisms 2022: It meets the requirements for absence of Escherichia coli in 10 g.
• Water Determination, Method I 921: NMT 0.1%. [Note500 mg of methylsulfonylmethane may be required for this analysis. ]
• Packaging and Storage: Preserve in well-closed containers.
• USP Reference Standards 11
USP Methylsulfonylmethane RS
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USP35NF30 Page 1383Pharmacopeial Forum: Volume No. 32(3) Page 826