Ethylparaben (Ethyl 4-hydroxybenzoate) CAS 120-47-8

Ethylparaben (Ethyl 4‑hydroxybenzoate) – Broad-Spectrum Preservative for Cosmetics, Pharmaceuticals, and Food

Basic Information

• CAS Number: 120-47-8

• Molecular Formula: C₉H₁₀O₃

• Molecular Weight: 166.17 g/mol

• Appearance: White crystalline powder

• Melting Point: 115–118°C

• Solubility: Slightly soluble in water; freely soluble in alcohol, propylene glycol, and oils

Overview
Ethylparaben (ethyl p‑hydroxybenzoate, E214) is a member of the paraben family of preservatives. It has been used for decades in cosmetic, pharmaceutical, and food products due to its excellent antimicrobial activity against a broad spectrum of bacteria, yeasts, and molds. Its stability, compatibility with various formulation ingredients, and cost‑effectiveness make it a reliable choice for product preservation.

Pharmacokinetics and Metabolism

• Penetration: Ethylparaben readily permeates the skin barrier, especially if the skin is compromised or if high concentrations are used.

• Metabolism: After absorption, it is rapidly hydrolyzed to p‑hydroxybenzoic acid and conjugated metabolites, which are excreted primarily in urine.

• Systemic toxicity: At typical use levels (0.1–0.4%), ethylparaben shows no significant systemic toxicity; however, local allergic reactions may occur in sensitive individuals.

Antimicrobial Activity
Ethylparaben acts by inhibiting microbial cell membrane function and enzyme systems, effectively controlling the growth of Gram‑positive and Gram‑negative bacteria, as well as yeasts and molds. Its activity is enhanced in combination with other parabens (e.g., methyl, propyl, butyl) and synergistic preservatives like phenoxyethanol.

Environmental Profile

• Water contamination: Residual parabens can be detected in wastewater after rinsing of personal care products.

• Biodegradation: Ethylparaben is biodegradable under aerobic conditions, though degradation rates vary with pH, temperature, and environmental conditions.

• Aquatic toxicity: Moderate toxicity to aquatic organisms at high concentrations, but levels in natural waters are generally low.

Applications

• Cosmetics and personal care: Creams, lotions, shampoos, makeup, sunscreens, and wet wipes.

• Pharmaceuticals: Oral suspensions, topical ointments, creams, and injectable formulations.

• Food: As E214 in baked goods, sauces, beverages, and preserved products.

• Industrial: As a biocide in paints, adhesives, and coatings.

Recommended Use
Typical usage levels: 0.1–0.4% in cosmetics and pharmaceuticals; 0.05–0.2% in food. The optimal concentration depends on the product type, pH, water activity, and the presence of other preservatives. Ethylparaben is often combined with other parabens (methyl, propyl) to achieve a broader spectrum and lower individual concentrations.

Regulatory and Safety Considerations

• Regulation: Ethylparaben is approved for use in cosmetics and food in the EU, US, Japan, and many other countries, with maximum allowable concentrations specified by local regulations.

• Sensitization: May cause contact dermatitis in a small percentage of individuals; patch testing is recommended for leave‑on products.

• Estrogenic activity: In vitro studies have shown weak estrogenic activity at very high doses, but this has not been established as clinically significant at normal use levels.

Trends and Alternatives

• Regulatory tightening: Some regions are reviewing maximum permissible levels of parabens in consumer products.

• Alternative preservatives: Organic acids (sorbates, benzoates) and plant‑derived extracts are gaining attention, though they may not match the efficacy or stability of parabens.

• Combination systems: Blending ethylparaben with other paraben esters and complementary antimicrobial agents (e.g., phenoxyethanol) allows reduced overall concentration while maintaining preservation.

Handling and Storage

• Store in a cool, dry, well‑ventilated area, away from light and strong oxidizers.

• Keep containers tightly sealed to prevent moisture absorption.

• Use appropriate personal protective equipment (gloves, safety goggles, dust mask) when handling.

• Avoid inhalation of dust and contact with skin and eyes.

Packaging
Available in 1 kg, 5 kg, 25 kg, and 50 kg containers (bags, drums, or boxes). Custom packaging upon request.

Quality Assurance
Each batch is tested for purity (by HPLC), melting point, and heavy metal content to ensure compliance with food, cosmetic, and pharmaceutical standards.