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Abstract
Cysteamine hydrochloride (CAS Number: 156-57-0) is a small, water-soluble aminothiol with critical biochemical and therapeutic applications.
This molecule serves as the active moiety in the treatment of cystinosis, a rare lysosomal storage disorder characterized by accumulation of cystine crystals in tissues.
Synonyms and Registration Data
Cysteamine hydrochloride is known by several synonyms, reflecting its varied usage in research, industrial, and clinical settings.
Common Synonyms:,2-Aminoethanethiol hydrochloride,Ethanethiol, 2-amino-, hydrochloride (1:1),2-Mercaptoethylamine hydrochloride,β-Mercaptoethylamine hydrochloride,Cysteaminium chloride,Merkamin hydrochloride,Mercamine hydrochloride,Cysteinamine hydrochloride,CI-9148, CT-2000,Cystadrops (ophthalmic formulation)
Beyond cystinosis therapy, cysteamine hydrochloride exhibits antioxidant properties, potential anticancer activity, and roles in radioprotection.
It functions primarily through intracellular thiol–disulfide exchange mechanisms, promoting cystine depletion via lysosomal cystine transporter interaction and modulating redox homeostasis.
This article details the compound's physicochemical properties, pharmacodynamics, metabolism, clinical use, safety profile, emerging applications, and regulatory considerations.
A thorough review of literature underscores its expanding role in medicine and biochemistry.
Introduction
Cysteamine hydrochloride (chemical formula: C₂H₈ClNS) is the hydrochloride salt of cysteamine (2-aminoethanethiol), a simple aminothiol derivative of cysteine lacking the carboxyl group.
It is a low molecular weight compound with a molecular mass of approximately 113.61 g/mol. Cysteamine was first synthesized in the early 20th century as a derivative of cysteine metabolism studies but gained clinical prominence in the late 20th century following the discovery of its efficacy in cystinosis treatment.
Cystinosis is a rare autosomal recessive disorder caused by mutations in the CTNS gene, leading to defective lysosomal cystine export.
This results in intracellular accumulation of cystine crystals, damaging multiple organs.
Cysteamine acts by converting cystine into cysteine and cysteine-cysteamine mixed disulfides, which can exit lysosomes via alternate transporters, thus reducing cystine accumulation.
In addition to its clinical role, cysteamine hydrochloride has been investigated for antioxidant capabilities, neuroprotective effects, and potential adjuvant use in oncology.
The molecule’s thiol group confers reducing properties critical to its biochemical activity.
Physicochemical Properties
Property Data
Molecular Formula C₂H₈ClNS
Molecular Weight 113.61 g/mol
CAS Number 156-57-0
Appearance White crystalline powder
Melting Point 67–71 °C
Solubility Freely soluble in water (~23.5 mg/mL at 25°C), soluble in ethanol, practically insoluble in ether
pKa Values Amino group ≈ 9.5; Thiol group ≈ 8.3
Log P (octanol-water) −0.3
Density ~1.2 g/cm³ (solid)
Chemical Structure HS–CH₂–CH₂–NH₂·HCl (See Figure 1)
Structural Details: The molecule consists of an ethane backbone bearing an amino group at one terminus and a thiol group at the other.
The hydrochloride moiety stabilizes the protonated amino group enhancing solubility and handling.
Figure 1: Chemical Structure of Cysteamine Hydrochloride
Registries:
CAS Registry Number: 156-57-0
UNII: IF1B771SVB
FDA Substance Registration System (SRS)
NCI Thesaurus Code: C169871
These synonyms are essential for cross-referencing among databases such as PubChem, ChemSpider, DrugBank, and suppliers like Sigma-Aldrich or Cayman Chemical.
Analytical and Reference Materials
Cysteamine hydrochloride is available as certified analytical standards to ensure quality control and reproducibility in research and pharmaceutical manufacturing.
Typical grades include ≥98% purity with trace metals and moisture characterized.
Standard Suppliers: Sigma-Aldrich (Product #PHR9273), Cayman Chemical, TCI Chemicals.
Analytical Techniques: Quantification and purity assessment typically use HPLC, NMR spectroscopy, and mass spectrometry.
Storage: Stable when stored at −20 °C, protected from moisture and oxidation. Hygroscopicity demands airtight containers.
Handling: Odor control due to thiol group volatility; gloves and fume hoods recommended.
Pharmacology & Biochemical Activity
Mechanism of Action
Cysteamine enters cells and lysosomes via passive diffusion and possibly transporters.
Inside lysosomes, cysteamine reacts with cystine to form cysteine and cysteine-cysteamine mixed disulfides.
These mixed disulfides can exit lysosomes through the lysine transporter, circumventing the defective cystinosin transporter in cystinosis.
Equation:
Cystine (Cys-S–S-Cys) + Cysteamine (HS–CH₂–CH₂–NH₂) → Cysteine + Cysteine-Cysteamine disulfide
This reduction of cystine accumulation prevents crystal formation, decreasing organ damage.
Antioxidant Activity
The thiol group of cysteamine can scavenge reactive oxygen species (ROS) such as hydrogen peroxide (H₂O₂) and hypochlorous acid (HOCl).
It also elevates intracellular glutathione (GSH) levels by providing cysteine, a rate-limiting substrate for GSH synthesis.
Other Biochemical Effects
Induction of heat shock proteins (HSP70), which protect cellular proteins under stress.
Modulation of apoptosis by altering redox-sensitive signaling pathways.
Radioprotective effects in vitro, by scavenging free radicals generated by ionizing radiation.
SAFETY INFORMATION ABOUT CYSTEAMINE HYDROCHLORIDE
First aid measures:
Description of first aid measures:
General advice:
Consult a physician.
Show this safety data sheet to the doctor in attendance.
Move out of dangerous area:
If inhaled:
If breathed in, move person into fresh air.
If not breathing, give artificial respiration.
Consult a physician.
In case of skin contact:
Take off conSAFETYtaminated clothing and shoes immediately.
Wash off with soap and plenty of water.
Consult a physician.
In case of eye contact:
Rinse thoroughly with plenty of water for at least 15 minutes and consult a physician.
Continue rinsing eyes during transport to hospital.
If swallowed:
Do NOT induce vomiting.
Never give anything by mouth to an unconscious person.
Rinse mouth with water.
Consult a physician.
Firefighting measures:
Extinguishing media:
Suitable extinguishing media:
Use water spray, alcohol-resistant foam, dry chemical or carbon dioxide.
Special hazards arising from the substance or mixture
Carbon oxides, Nitrogen oxides (NOx), Hydrogen chloride gas
Advice for firefighters:
Wear self-contained breathing apparatus for firefighting if necessary.
Accidental release measures:
Personal precautions, protective equipment and emergency procedures
Use personal protective equipment.
Avoid breathing vapours, mist or gas.
Evacuate personnel to safe areas.
Environmental precautions:
Prevent further leakage or spillage if safe to do so.
Do not let product enter drains.
Discharge into the environment must be avoided.
Methods and materials for containment and cleaning up:
Soak up with inert absorbent material and dispose of as hazardous waste.
Keep in suitable, closed containers for disposal.
Handling and storage:
Precautions for safe handling:
Avoid inhalation of vapour or mist.
Conditions for safe storage, including any incompatibilities:
Keep container tightly closed in a dry and well-ventilated place.
Containers which are opened must be carefully resealed and kept upright to prevent leakage.
Storage class (TRGS 510): 8A: Combustible, corrosive hazardous materials
Exposure controls/personal protection:
Control parameters:
Components with workplace control parameters
Contains no substances with occupational exposure limit values.
Exposure controls:
Appropriate engineering controls:
Handle in accordance with good industrial hygiene and safety practice.
Wash hands before breaks and at the end of workday.
Personal protective equipment:
Eye/face protection:
Tightly fitting safety goggles.
Faceshield (8-inch minimum).
Use equipment for eye protection tested and approved under appropriate government standards such as NIOSH (US) or EN 166(EU).
Skin protection:
Handle with gloves.
Gloves must be inspected prior to use.
Use proper glove
removal technique (without touching glove's outer surface) to avoid skin contact with this product.
Dispose of contaminated gloves after use in accordance with applicable laws and good laboratory practices.
Wash and dry hands.
Full contact:
Material: Nitrile rubber
Minimum layer thickness: 0.11 mm
Break through time: 480 min
Material tested:Dermatril (KCL 740 / Aldrich Z677272, Size M)
Splash contact
Material: Nitrile rubber
Minimum layer thickness: 0.11 mm
Break through time: 480 min
Material tested:Dermatril (KCL 740 / Aldrich Z677272, Size M)
It should not be construed as offering an approval for any specific use scenario.
Body Protection:
Complete suit protecting against chemicals, The type of protective equipment must be selected according to the concentration and amount of the dangerous substance at the specific workplace.
Respiratory protection:
Where risk assessment shows air-purifying respirators are appropriate use a fullface respirator with multi-purpose combination (US) or type ABEK (EN 14387) respirator cartridges as a backup to engineering controls.
If the respirator is the sole means of protection, use a full-face supplied air respirator.
Use respirators and components tested and approved under appropriate government standards such as NIOSH (US) or CEN (EU).
Control of environmental exposure
Prevent further leakage or spillage if safe to do so.
Do not let product enter drains.
Discharge into the environment must be avoided.
Stability and reactivity:
Chemical stability:
Stable under recommended storage conditions.
Incompatible materials:
Strong oxidizing agents:
Hazardous decomposition products:
Hazardous decomposition products formed under fire conditions.
Carbon oxides, Nitrogen oxides (NOx), Hydrogen chloride gas.
Disposal considerations:
Waste treatment methods:
Product:
Offer surplus and non-recyclable solutions to a licensed disposal company.
Contact a licensed professional waste disposal service to dispose of this material.
Contaminated packaging:
Dispose of as unused product
