Phenyl benzimidazole sulfonic acid

Public-database records for Phenyl benzimidazole sulfonic acid (CAS 27503-81-7), reproduced here for independent cross-checking.

Safety classification and hazard statements

Regulatory listings

Physical description and handling notes

• >300, decomposes at 410
• Soluble
• Ensulizole is a selective UV-B filter with little activity against UV-A wavelengths. _In vitro_, ensulizole oxidizes guanine bases upon photoexcitation by UV-B and may cause photodamage on DNA, proteins and lipids in the cellular context.

How this substance is indexed

Documented uses

• Cosmetics -> Uv filter; Uv absorber
• Information on 7 consumer products that contain Phenylbenzimidazole sulfonic acid in the following categories is provided:
• 1H-Benzimidazole-6-sulfonic acid, 2-phenyl-: ACTIVE
• Indicated to be used as an UV-B-absorbing molecule in sunscreen formulations.
• A 2025 review by authors in the U.S. and U.K. used experimentally determined values of 4% for oral absorption in rats and 0.26% for dermal absorption in humans for their risk calculation purposes. Also, the authors noted no evidence of bioaccumulation in rat vivo studies, which they stated is consistent with the high water solubility and low octanol/water partition coefficient.
• Ensulizole strongly absorbs UV-B wavelengths. It offers protection against UV-B-induced cyclobutane pyrimidine dimers. Based on the findings in vitro and in cellulo, ensulizole induces damage on the DNA, causes DNA strand breaks and photosensitizes the formation of oxidized guanines via type I and II photosensitization mechanisms following UV-A or UV-B irradiation. Ensulizole is capable of generating reactive oxygen species, including singlet oxygen upon photoexcitation.

Names this substance appears under

Ensulizole; 27503-81-7; 2-PHENYLBENZIMIDAZOLE-5-SULFONIC ACID; Phenylbenzimidazole sulfonic acid; ensulizol; DTXSID3038852; 9YQ9DI1W42; 1H-Benzimidazole-5-sulfonic acid-2-phenyl-; DTXCID1018852; 2-phenyl-1H-1,3-benzodiazole-6-sulfonic acid; ensulizolum; novantisol; RefChem:55096; Covergirl Outlast Stay Fabulous 3in1 Foundation; FULL SPECTRUM MATTE AMBITION SKIN PRIMER SPF 20; Covergirl Queen Collection All Day Flawless 3in1 Foundation

Computed molecular descriptors

Database abstract

Phenyl benzimidazole sulfonic acid · CAS 27503-81-7 · C13H10N2O3S. UNII 9YQ9DI1W42.

Source: PubChem / Wikidata; the batch COA governs where values differ.