L-Thyroxine
[CAS# 51-48-9]

Identification

• Classification: API >> Hormone and endocrine-regulating drugs >> Thyroid hormone and antithyroid drugs
• Name: L-Thyroxine
• Synonyms: 3,3',5,5'-Tetraiodo-L-thyronine; 3-[4-(4-Hydroxy-3,5-diiodophenoxy)-3,5-diiodophenyl]-L-alanine; L-2-Amino-3-[4-(4-hydroxy-3,5-diiodo-phenoxy)-3,5-diiodo-phenyl]-propanoic acid
• Molecular Formula: C₁₅H₁₁I₄NO₄
• Molecular Weight: 776.87
• CAS Registry Number: 51-48-9
• EC Number: 200-101-1

Properties

• Melting point: 223 ºC (dec.)
• alpha: -5 º (1N NaOH:EtOH 1:2)
• Water solubility: insoluble

Safety Data

• Safety Description: S24/25

Hazard Classification

Hazard	Class	Category Code	Hazard Statement
Acute toxicity	Acute Tox.	4	H302
Reproductive toxicity	Repr.	2	H361
Specific target organ toxicity - repeated exposure	STOT RE	1	H372
Specific target organ toxicity - repeated exposure	STOT RE	2	H373
Acute toxicity	Acute Tox.	4	H312
Skin sensitization	Skin Sens.	1	H317
Specific target organ toxicity - single exposure	STOT SE	1	H370
Acute toxicity	Acute Tox.	4	H332