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Annex II Entry 91 17/10/2010

Chlormezanone (INN)

Chlormezanone (INN) is listed in Annex II as a prohibited substance for cosmetic products placed on the EU market.

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Prohibited substance— Annex II, EU Regulation 1223/2009
Entry: 91

Chemical identity and properties

PubChem 2D chemical structure for CAS 80-77-3
CAS 80-77-3PubChem CID 2717

Chlormezanone

Chlormezanone is a 1,3-thiazine that is 1,3-thiazinan-4-one S,S-dioxide in which a hydrogen at position 2 is substituted by a 4-chlorophenyl group and the hydrogen attached to the nitrogen is substituted by methyl. A non-benzodiazepine muscle relaxant, it was used in the management of anxiety and in the treatment of muscle spasms until being discontinued worldwide by its manufacturer in 1996, due to rare but serious cutaneous reactions. It has a role as an anxiolytic drug, an antipsychotic agent and a muscle relaxant. It is a lactam, a sulfone, a 1,3-thiazine and a member of monochlorobenzenes. — ChEBI

IUPAC name
2-(4-chlorophenyl)-3-methyl-1,1-dioxo-1,3-thiazinan-4-one
Molecular formula
C11H12ClNO3S
Molecular weight
273.74 g/mol
Exact mass
273.0226421 Da
XLogP3
1.1
Topological polar surface area
62.8 Ų
Hydrogen-bond donors
0
Hydrogen-bond acceptors
3
Covalent units
1
Defined stereocentres
0

Also known as

ChlormethazanoneTrancopalChlormethazoneChlormezanonClormetazanoneClormetazonPhenaroldl-Chlormezanone
16 more reported names
BanabinClorilaxMiorilaxRilansylRilaquilRilassolSupotranTanafolBisinaRexanRilaxBanabin-sintyalMio-sedBanabil-sintyalChlormezanonumClormezanona
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External database identifiers

Retrieved from NIH PubChem on 2026-08-31 by checksum-valid CAS matching. Chemical properties do not replace the regulatory decision on this page.

Record details

Chemical name

Chlormezanone (INN)

Chemical / IUPAC name

2-(p-Chlorophenyl)tetrahydro-3-methyl-4H-1,3-thiazin-4-one 1,1-dioxide

Regulatory information

Regulation

(EC) 2009/1223

See every entry this act set

Key data

CAS
80-77-3
EC
201-307-4
Annex
II
Entry number
91

Direct matches are limited for this record, so nearby entries from Annex II are shown as well.

Annex II 96
Nearby record in the same annex

Chloroethane

CAS: 75-00-3
EC: 200-830-5

What Annex II means for Chlormezanone (INN)

Chlormezanone (INN) is listed as a prohibited substance under Annex II of EU Cosmetics Regulation 1223/2009 and must not be intentionally added. Article 17 separately addresses unintended small quantities that are technically unavoidable under good manufacturing practice and compatible with the Article 3 safety requirement.

Formulators must screen their ingredients and raw materials to ensure none contain this substance. Suppliers should provide documentation confirming absence when requested.

The page also surfaces 12 related annex records with overlapping identifiers, annex logic or naming patterns.

Compliance checklist

  • Verify this substance is absent from all raw materials and finished formulations.
  • Request absence confirmation or CoA from raw material suppliers.
  • Document the screening result in the Product Information File (PIF).

Frequently asked questions

Yes. Chlormezanone (INN) is listed in Annex II of EU Cosmetics Regulation 1223/2009 and is prohibited as an intentionally added cosmetic ingredient. Article 17 provides a narrow exception for unintended small quantities that are technically unavoidable under good manufacturing practice, provided the product remains safe under Article 3.

CAS 80-77-3 is the unique numerical identifier assigned to Chlormezanone (INN) by the Chemical Abstracts Service. In cosmetic compliance work, the CAS number is used to cross-reference the substance across regulatory databases, raw material specifications and safety assessment reports. Multiple EU annex entries may share the same CAS number if the same substance appears under different conditions or in different annexes.

Use the INCI Checker tool on this site to paste your full ingredient list (INCI) and scan it against all Annex II–VI entries. The tool highlights any ingredients that match restricted, prohibited or allergen-flagged records. This is useful for rapid compliance screening of finished product formulas or raw material declarations.
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Source note for Annex II record Chlormezanone (INN)

This page summarizes one Annex II record for Chlormezanone (INN) from public European Commission cosmetic materials and adds linked inventory or identifier matches when available.

Use this record page to review Annex II conditions for Chlormezanone (INN), but confirm any final regulatory decision against the current official annex wording and source files.

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