Title: Carbocysteine
CAS Registry Number: 638-23-3
CAS Name: S-(Carboxymethyl)-L-cysteine
Additional Names: 3-[(carboxymethyl)thio]alanine; S-carboxymethylcysteine
Manufacturers' Codes: AHR-3053; LJ-206
Trademarks: Carbocit (CT); Fluifort (Domp?; Lisomucil (Sanofi-Synthelabo); Loviscol (Wyeth); Muciclar (Pfizer); Mucocis (So.Se.); Mucodyne (Sanofi-Aventis); Mucolase (Lampugnani); Mucolex (Warner-Lambert); Mucopront (Mack, Illert.); Pectox (Italfarmaco); Pulmoclase (UCB); Reomucil (DOC); Rhinathiol (Sanofi-Synthelabo); Siroxyl (Aventis); Transbronchin (Viatris)
Molecular Formula: C5H9NO4S
Molecular Weight: 179.19
Percent Composition: C 33.51%, H 5.06%, N 7.82%, O 35.71%, S 17.89%
Literature References: Prepn: Armstrong, Lewis, J. Org. Chem. 16, 749 (1951); Schöberl, Wagner, Z. Physiol. Chem. 304, 97 (1956); Foye, Verderame, J. Am. Pharm. Assoc. 46, 273 (1957); Goodman et al., J. Org. Chem. 23, 1251 (1958). Pharmacology: Huyen-Vu-Ngoc et al., C.R. Seances Soc. Biol. Ses Fil. 160, 1849 (1966); Quevauviller et al., Therapie 22, 485 (1967). Clinical trial in chronic bronchitis: M. Grillage, K. Bernard-Jones, Br. J. Clin. Pract. 39, 395 (1985). Review of pharmacology and clinical uses: D. T. Brown, Drug Intell. Clin. Pharm. 22, 603-608 (1988).
Derivative Type: L-Form
Properties: mp 204-207°. [a]D24 +0.5° (1N HCl).
Melting point: mp 204-207°
Optical Rotation: [a]D24 +0.5° (1N HCl)
Derivative Type: DL-Form
Properties: Spherical aggregates of needles.
Therap-Cat: Mucolytic; expectorant.
Keywords: Expectorant; Mucolytic.
Carbofuran Carbohydrazide Carbomycin Carbon Diselenide Carbon Disulfide

Carboxymethylcystein Formulae.png
CAS number 638-23-3 (R) YesY, 2387-59-9 (RS)
PubChem 193653
ChemSpider 168055 YesY
DrugBank DB04339
KEGG D06393 YesY
ChEBI CHEBI:16163 YesY
ATC code R05CB03
Jmol-3D images Image 1
Image 2
Molecular formula C5H9NO4S
Molar mass 179.19 g mol−1
Appearance Colorless solid
Melting point 204–207 °C
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Except where noted otherwise, data are given for materials in their standard state (at 25 °C (77 °F), 100 kPa)
Infobox references
Carbocisteine molecule, in 3D

Carbocisteine is a mucolytic that reduces the viscosity of sputum and so can be used to help relieve the symptoms of chronic obstructive pulmonary disorder (COPD) and bronchiectasis by allowing the sufferer to bring up sputum more easily. Carbocisteine should not be used with antitussives (cough suppressants) or medicines that dry up bronchial secretions.

Carbocisteine is produced by alkylation of cysteine with chloroacetic acid.[1]