Phenylbenzimidazole sulfonic acid

Ensulizole (INN; also known as phenylbenzimidazole sulfonic acid) is a common sunscreen agent. In 1999, the United States Food and Drug Administration regulated that the name ensulizole be used on sunscreen labels in the United States. Ensulizole is primarily a UVB protecting agent providing only minimal UVA protection. The scope of UVB is 290 to 340 nanometers whereas the UVA range is 320 to 400 nanometers. For better UVA protection, it must be paired with avobenzone, titanium dioxide, or zinc oxide; outside of the United States it can also be paired with a UV absorber of the Tinosorb or Mexoryl types. Because ensulizole is water-soluble, it has the characteristic of feeling lighter on skin. As such, it is often used in sunscreen lotions or moisturizers whose aesthetic goal is a non-greasy finish. The free acid is poorly soluble in water, so it is only used as its soluble salts.

Ensulizole

Names
IUPAC name 2-Phenyl-3H-benzimidazole-5-sulfonic acid
Identifiers
CAS Number	27503-81-7 Y
3D model (JSmol)	Interactive image
ChemSpider	31267 Y
ECHA InfoCard	100.044.078
KEGG	D10005 N
PubChem CID	33919
UNII	9YQ9DI1W42 Y
CompTox Dashboard (EPA)	DTXSID3038852
InChI InChI=1S/C13H10N2O3S/c16-19(17,18)10-6-7-11-12(8-10)15-13(14-11)9-4-2-1-3-5-9/h1-8H,(H,14,15)(H,16,17,18) Y Key: UVCJGUGAGLDPAA-UHFFFAOYSA-N Y InChI=1/C13H10N2O3S/c16-19(17,18)10-6-7-11-12(8-10)15-13(14-11)9-4-2-1-3-5-9/h1-8H,(H,14,15)(H,16,17,18) Key: UVCJGUGAGLDPAA-UHFFFAOYAY
SMILES O=S(=O)(O)c3ccc2[nH]c(c1ccccc1)nc2c3
Properties
Chemical formula	C13H10N2O3S
Molar mass	274.29 g·mol−1
Hazards
Safety data sheet (SDS)	Cole Parmer Material Safety Data Sheet
Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa). N verify (what is YN ?) Infobox references