Propyl Gallate is an antioxidant commonly used in food, pharmaceuticals, and cosmetics to prevent oxidation and extend shelf life. It is the propyl ester of gallic acid, known for stabilizing fats, oils, and active pharmaceutical ingredients (APIs) susceptible to oxidative degradation. In pharmaceuticals, it is mainly used as an excipient in topical and oral formulations.
It is recognized for its synergistic antioxidant effect when combined with other agents like BHA (butylated hydroxyanisole) or BHT (butylated hydroxytoluene).
Therapeutic and industrial applications include:
• Antioxidant in pharmaceutical formulations
• Stabilizer in food products and dietary supplements
• Antioxidant in cosmetics and personal care products
• Used in veterinary and animal feed preparations
Parent: Propyl Gallate
Parent: Propyl Gallate
Parent: Propyl Gallate
Parent: Propyl Gallate
Impurities in propyl gallate can arise from raw materials, esterification conditions, or degradation during storage. Proper control of these impurities is essential to meet pharmacopeial standards (USP, EP, JP) and ICH Q3A/B impurity limits for excipients and APIs.
Process-Related Impurities
• Unreacted gallic acid
• Unreacted propanol or over-esterified by-products
• Residual solvents like ethanol, methanol, or toluene
• By-products from acidic or basic catalysis used during esterification
Degradation Impurities
• Oxidation products (quinones or polymeric species) under air/light exposure
• Hydrolysis of the ester bond leading to free gallic acid and propanol
• Discoloration due to polymerization or breakdown of phenolic structure
Elemental Impurities
• Trace metals like iron, copper, or tin that can catalyze oxidation
• Must comply with ICH Q3D limits, particularly for oral/topical use
Analytical Techniques for Impurity Detection
Propyl Gallate is used as an antioxidant to prevent oxidation of fats, oils, and sensitive pharmaceutical or cosmetic ingredients.
It scavenges free radicals and interrupts oxidative chain reactions, thereby preserving product integrity and extending shelf life.
It is semi-synthetic—derived from gallic acid, which can be obtained from natural sources, but chemically esterified with propanol.
Store in a tightly closed container, protected from light, moisture, and air. Recommended storage temperature is below 25°C.
