Glycerin 99.7% USP
Glycerin 99.7% USP (United States Pharmacopeia) is a high-purity, colorless, odorless, and viscous liquid commonly used in pharmaceutical, cosmetic, and food applications. It is a trihydroxy alcohol (C₃H₈O₃) known for its excellent humectant, solvent, and emollient properties. In pharmaceuticals, it is widely used in oral, topical, and parenteral preparations to retain moisture, improve texture, and enhance solubility. Its purity level of 99.7% makes it suitable for use in sensitive formulations and ensures compliance with stringent regulatory standards.

USP Specification for Glycerin 99.7%

• Purity: Not less than 99.7% w/w (calculated as C₃H₈O₃).
• Appearance: Clear, colorless, viscous liquid.
• Odor: Odorless or nearly odorless.
• Identification: Passes tests for glycerol using infrared absorption or chemical methods.
• Specific Gravity: Between 1.249 and 1.258 at 25°C.
• Refractive Index: Between 1.4700 and 1.4750 at 20°C.
• Acidity or Alkalinity: Passes test (should be neutral to slightly acidic).
• Chlorinated Compounds: Passes test (limit of chlorinated compounds to ensure safety).
• Residue on Ignition: Not more than 0.01%.
• Heavy Metals: Not more than 5 ppm.
• Diethylene Glycol and Ethylene Glycol: Must comply with limit tests (typically <0.1%).
• Water Content: Typically ≤0.3% (Karl Fischer method).