Why does CAS 27503-81-7 appear in more than one EU cosmetic annex?

A substance identified by CAS 27503-81-7 may appear in multiple EU cosmetic regulation annexes when it is subject to different conditions in different contexts — for example, restricted under Annex III with specific conditions, while also appearing in Annex IV as an approved colorant under separate entry conditions. Each entry must be reviewed individually.

How do I check if my formula contains a substance with CAS 27503-81-7?

Use the INCI Checker on CosIng Checker with INCI names, CAS numbers or EC numbers. Paste CAS 27503-81-7 to screen it directly, then review every linked annex record and supplier document.

CAS 1 record

CAS 27503-81-7

Q: How do I use CAS 27503-81-7 for compliance screening?

Cross-reference CAS 27503-81-7 against your raw material specification sheets and CoA documents. When it appears in Annex II, verify absence. When it appears in Annex III, verify that concentration limits and product type conditions are met. All annex entries sharing this CAS number are listed on this page.

CAS 27503-81-7 matches 1 EU annex record across Annex II–VI of Regulation 1223/2009.

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Chemical identity and properties

PubChem 2D chemical structure for CAS 27503-81-7

CAS 27503-81-7PubChem CID 33919

2-Phenylbenzimidazole-5-Sulfonic Acid

Ensulizole is a member of benzimidazoles. — ChEBI

IUPAC name: 2-phenyl-3H-benzimidazole-5-sulfonic acid

Molecular formula: C13H10N2O3S
Molecular weight: 274.30 g/mol
Exact mass: 274.04121336 Da
XLogP3: 2.0
Topological polar surface area: 91.4 Å²
Hydrogen-bond donors: 2
Hydrogen-bond acceptors: 4
Covalent units: 1
Defined stereocentres: 0

Also known as

EnsulizolePhenylbenzimidazole sulfonic acidensulizol9YQ9DI1W421H-Benzimidazole-5-sulfonic acid-2-phenyl-2-phenyl-1H-1,3-benzodiazole-6-sulfonic acidensulizolumnovantisol

16 more reported names

RefChem:55096Covergirl Outlast Stay Fabulous 3in1 FoundationFULL SPECTRUM MATTE AMBITION SKIN PRIMER SPF 20Covergirl Queen Collection All Day Flawless 3in1 FoundationCovergirl TruBlend Base Business Everyday Defense Primer SPF 20Prada Reveal Skin Optimizing Foundation Broad Spectrum SPF 17 SunscreenCovergirl Outlast Stay Fabulous 3in1 Foundation Broad spectrum SPF 20-805 IvoryCovergirl Outlast Stay Fabulous 3in1 Foundation Broad spectrum SPF 20-810 Classic IvoryCovergirl Outlast Stay Fabulous 3in1 Foundation Broad spectrum SPF 20-820 CreamyCovergirl Outlast Stay Fabulous 3in1 Foundation Broad spectrum SPF 20-825 Buff BeigeCovergirl Outlast Stay Fabulous 3in1 Foundation Broad spectrum SPF 20-832 Nude BeigeCovergirl Outlast Stay Fabulous 3in1 Foundation Broad spectrum SPF 20-840 Natural BeigeCovergirl Outlast Stay Fabulous 3in1 Foundation Broad spectrum SPF 20-842 Medium BeigeCovergirl Outlast Stay Fabulous 3in1 Foundation Broad spectrum SPF 20-845 Warm BeigeCovergirl Outlast Stay Fabulous 3in1 Foundation Broad spectrum SPF 20-850 Creamy BeigeCovergirl Outlast Stay Fabulous 3in1 Foundation Broad spectrum SPF 20-855 Soft Honey

Open full PubChem record PubChem annotations 3D structure image

External database identifiers

ChEBI:CHEBI:135132
ChEMBL:CHEMBL1987518
EPA DTXSID:DTXSID3038852
PubMed:23112351
PubMed:22189380
PubMed:22098937
PubMed:21453950
PubMed:20836551
PubMed:20681737
PubMed:20574440
PubMed:18968944
PubMed:18371796
PubMed:18275177
PubMed:18217772
PubMed:16956250

Retrieved from NIH PubChem on 2026-09-02 by checksum-valid CAS matching. Chemical properties do not replace the regulatory decision on this page.

Records for CAS 27503-81-7

1 total

Annex

Entry

PHENYLBENZIMIDAZOLE SULFONIC ACID

2-Phenylbenzimidazole-5-sulphonic acid and its potassium, sodium and triethanolamine salts / Ensulizole

248-502-0

Max concentration

How CAS 27503-81-7 is used on this site

CAS 27503-81-7 is the Chemical Abstracts Service identifier used to pin this page to a specific substance. In the current dataset, 1 EU annex record shares this identifier, which helps you cross-check whether the same substance appears under one regulatory context or several.

Use this page when a supplier specification, SDS or raw-material dossier gives you CAS 27503-81-7 and you need to see every linked Annex II–VI record in one place. The entry cards above are the quickest route to concentration limits, warnings, annex placement and product-type conditions.

Frequently asked questions

A substance identified by CAS 27503-81-7 may appear in multiple EU cosmetic regulation annexes when it is subject to different conditions in different contexts. For example, a substance might be restricted under Annex III with specific conditions, and the same CAS might also appear in Annex IV as an approved colorant under separate entry conditions. Each entry must be reviewed individually.

Cross-reference the CAS number against your raw material specification sheets and CoA documents. When a CAS appears in Annex II, verify absence. When it appears in Annex III, verify that concentration limits and product type conditions are met in your formulation. All annex entries sharing this CAS number are listed above.

A CAS number is assigned by the Chemical Abstracts Service (USA) and is globally recognised. An EC number is a European Commission identifier from inventories such as EINECS, ELINCS or the NLP list. Both identifiers may appear in EU cosmetic annex entries. Some substances have both, some have only one, and some older entries may have neither.

The INCI Checker accepts ingredient names, CAS numbers and EC numbers. Check this CAS number directly, then verify the result against supplier specification sheets and every linked annex condition.

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