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Pigments & Colorants

Phenylbenzimidazole sulfonic acid

CAS: 27503-81-7

Overview

Phenylbenzimidazole sulfonic acid ( CAS 27503-81-7 ), commonly abbreviated as PBSA, is a water-soluble UV filter used primarily in sun care and personal care formulations. Unlike oil-soluble UV absorbers, its water solubility makes it suitable for aqueous and hydrophilic systems.

This chemical is ideal for applications where broad-spectrum UVB protection is required. PBSA is a regulated UVB-filtering active in sunscreens, functioning across lotions, sprays, and gel formulations where water-phase UV protection is needed.

In pharmaceutical topical preparations, it provides photostabilization to light-sensitive active ingredients, extending product shelf life and efficacy. Personal care manufacturers incorporate it into daily moisturizers and after-sun products.

These formulations deliver UVB protection without compromising texture or transparency. It also appears in combination UV filter systems alongside UVA absorbers, where its water solubility complements oil-phase actives to achieve full-spectrum coverage.

PBSA is supplied as a white to off-white crystalline powder. It is available in cosmetic-grade and pharmaceutical-grade specifications, with purity levels typically at 98% or higher to meet regulatory requirements in sun care markets.

Suppliers commonly offer it in compliance with EU Cosmetics Regulation and equivalent international standards governing UV filter actives. The material is often tested against USP and Ph.Eur. standards to ensure safety and performance.

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Physical Properties

Melting Point>300 °C (lit.)
Density1.3592 (rough estimate)
Appearancewhite fine crystalline powder
ColorWhite
FormFine Crystalline Powder
Water Solubilitysoluble
Refractive Index1.6360 (estimate)
Log P-1.42 at 25℃

Safety & Handling

Warning GHS07 Hazard Statements H315 Causes skin irritation H319 Causes serious eye irritation Precautionary Statements P264 Wash … thoroughly after handling. P280 Wear protective gloves/protective clothing/eye protection/face protection. P321 Specific treatment (see … on this label). P264+P265 Wash … thoroughly after handling. P302+P352 IF ON SKIN: Wash with plenty of water. P332+P317 Get emergency medical help. P337+P317 If eye irritation persists: Get medical advice/attention. Get emergency medical help. P362+P364 Take off contaminated clothing and wash it before reuse. P305+P351+P338 IF IN EYES: Rinse cautiously with water for several minutes. Remove contact lenses, if present and easy to do. Continue rinsing.

Trade & Regulatory

HS Code29339990
Storage Class11 - Combustible Solids
WGK (Germany)3

Other Names

2-phenylbenzimidazole-5-sulfonic acid | 2-phenyl-3h-benzimidazole-5-sulfonic acid | Ensulizole | PBSA

Related Products

Chemical Properties

CAS Number
27503-81-7
EC Number
248-502-0
Mol. Weight
274.30
HS Code
29339990

Industries

Documentation