Propylene Glycol 50% – USP Grade (C3H8O2)

Product Overview

Propylene Glycol 50% – USP Grade (C3H8O2) is a colorless, odorless, and hygroscopic diol that functions as a versatile solvent and humectant across pharmaceutical, food, and cosmetic applications. This USP-grade formulation offers a defined assay range (99.0–100.5% with a typical of 99.5%), low color (APHA ≤10 with typical ~5), and stringent impurity limits designed to support stringent quality requirements in regulated environments. The product demonstrates a density near 1.033–1.037 g/mL across 20–25°C, a relatively low vapor pressure (0.13 mmHg at 20°C), and a modest boiling range around 188.2°C, which together promote predictable performance in liquid formulations, extractions, and as a phase-transfer component. Its comprehensive specification set ensures compatibility with USP-NF Monographs and aligns with industry expectations for safety, purity, and traceability.

For GMP-conscious manufacturers, the 50% solution provides reliable humectancy, viscosity control, and solvent capabilities while maintaining storage stability under standard pharmaceutical handling practices. The product is suitable for use in analytical, food, and pharmaceutical pipelines where precise water content control, minimal aldehyde content, and trace metal limits are critical for efficacy and safety. This propylene glycol solution also serves as a dependable component in HPLC mobile phases, topical and oral drug formulations, and as a moisture-retaining additive in a variety of consumer and professional products.

Key Properties

• Property Name: Assay Weight Percent (min–max)
• Chemical Formula: C₃H₈O₂
• Molecular Weight: 76.09 g/mol
• Boiling Point: 188.2°C
• Specific Gravity (20°C): 1.035–1.037 (typical 1.036)
• Specific Gravity (25°C): 1.033–1.036 (typical 1.035)
• Water Content: 0.0–0.2 wt% (typical 0.1)
• Residue on Ignition: ≤0.005 wt% (typical 0.001)
• Chloride (Cl⁻): ≤10 ppm (typical 2)
• Nitrate (NO₃⁻): ≤20 ppm (typical 5)
• Ammonium (NH₄⁺): ≤5 ppm (typical 1)
• Sulfate (SO₄²⁻): ≤20 ppm (typical 5)
• Phosphate (PO₄³⁻): ≤5 ppm (typical 1)
• Arsenic (As): ≤0.5 ppm (typical 0.05)
• Heavy Metals (as Pb): ≤0.1 ppm (typical 0.02)
• Iron (Fe): ≤0.2 ppm (typical 0.05)
• Copper (Cu): ≤0.5 ppm (typical 0.1)
• Manganese (Mn): ≤0.5 ppm (typical 0.1)
• Nickel (Ni): ≤0.5 ppm (typical 0.1)
• Lead (Pb): ≤0.5 ppm (typical 0.1)
• Zinc (Zn): ≤1 ppm (typical 0.2)
• Aluminum (Al): ≤2 ppm (typical 0.5)
• Chromium (Cr): ≤0.5 ppm (typical 0.1)
• Cobalt (Co): ≤0.2 ppm (typical 0.05)
• Calcium (Ca): ≤2 ppm (typical 0.5)
• Magnesium (Mg): ≤5 ppm (typical 1)
• Sodium (Na): ≤2 ppm (typical 0.5)
• Sulfurous acid content: ≤5 ppm (typical 1)
• Available Chlorine: ≤0.5 wt% (typical 0.1)
• Acidity (Meq/g): ≤0.1 (typical 0.02)
• Aldehydes: ≤0.5 ppm (typical 0.1)

Common Applications

• HPLC Mobile Phase: Analytical Chemistry – Used as a mobile phase component in reversed-phase chromatography to improve solubility and peak shape for organic compounds.
• Humectant in Food Products: Food Industry – Moisture-retaining agent that helps preserve texture and freshness in formulations where water activity control is critical.
• Solvent for Pharmaceuticals: Pharmaceutical – Solvent in formulation of oral, injectable, and topical dosage forms with acceptable safety margins for USP-grade products.
• Antifreeze Agent: Industrial – Lower freezing point component in antifreeze blends, contributing to system stability in temperature-varied environments.
• Cosmetic Ingredient: Personal Care – Moisturizer and solvent in cosmetic emulsions and homogeneous solutions for stable product performance.
• Industrial Cleaning Formulations: Industrial – Component in cleaning and processing fluids where low-to-moderate polarity solvents are required.
• Binder and Humectant in Coatings: Materials – Helps control drying and moisture content in specialty coatings and polymer formulations.

Safety Precautions

Store propylene glycol 50% USP grade in a cool, dry place away from direct sunlight. Containers should be HDPE or glass to avoid interaction and maintain purity. Keep the product away from strong oxidizers and acids and ensure proper ventilation during handling to minimize inhalation exposure. Use appropriate PPE including gloves and goggles when handling, and ensure spill control measures are in place to prevent environmental release. Follow the SDS and applicable regulatory guidelines during transport and storage.

When expanding or transferring containers, maintain an inert atmosphere if feasible to minimize moisture uptake and maintain consistent quality. Adhere to exposure controls and engineering controls; monitor workplace air as necessary and follow standard operating procedures for handling liquids with USP-grade specifications. In case of contact with eyes or skin, flush with water and seek medical attention if irritation persists. Follow emergency procedures for spills, including containment, ventilation, and proper waste disposal according to local regulations.

Benefits

✔ USP-Grade Purity – Meets USP-NF Monograph requirements with tight assay, minimal impurities, and compliance verification.
✔ Stable Physical Properties – Consistent density, viscosity, and boiling range across temperature ranges suitable for precise formulation work.
✔ Low Impurity Profile – Stringent limits for heavy metals, halides, nitrates, and aldehydes reduce risk of unwanted reactions in sensitive formulations.
✔ Designed for GMP Environments – Suitable for pharmaceutical, food, and cosmetic applications with clear storage and handling guidelines.