Description

L-Thyroxine is the synthetic form of the endogenous thyroid hormone thyroxine (T4), a critical regulator of metabolism, growth, and development. This high-purity active pharmaceutical ingredient (API) is essential for the formulation of consistent and effective thyroid hormone replacement therapies. It is primarily required by pharmaceutical manufacturers for producing tablets, capsules, and other dosage forms to treat conditions such as hypothyroidism, goiter, and thyroid cancer.

Application

• Pharmaceutical API: Primary use as the active ingredient in thyroid hormone replacement medications (e.g., Levothyroxine Sodium tablets).
• Veterinary Medicine: Formulation of treatments for hypothyroidism in companion animals and livestock.
• Biochemical Research: Used as a standard or reagent in endocrine, metabolic, and cell signaling studies.
• Diagnostic Kits: Component in immunoassay kits for the calibration and quality control of thyroid function tests.
• Reference Standard: Serves as a pharmacopeial reference standard (USP, EP) for quality control testing.

Basic Information

Product Name	L-Thyroxine
CAS No.	51-48-9
Molecular Formula	C15H11I4NO4
Molecular Weight	776.87 g/mol
Synonyms	Levothyroxine; Thyroxine; T4; 3,5,3',5'-Tetraiodo-L-thyronine; (2S)-2-Amino-3-[4-(4-hydroxy-3,5-diiodophenoxy)-3,5-diiodophenyl]propanoic acid; Synthroid (brand name); Levoxyl (brand name); Euthyrox (brand name)
EINECS	200-101-1

Quality Control

Our L-Thyroxine is manufactured under strict quality management systems, targeting compliance with major pharmacopeial standards such as USP and EP. Every batch undergoes comprehensive analytical testing including HPLC assay, related substances profiling, residual solvent analysis, and identity confirmation. A detailed Certificate of Analysis (COA) is provided with each shipment to ensure full traceability and specification compliance.

Storage

Preserve in a tightly closed container, protected from light. Store in a cool, dry place at a controlled room temperature (15-25°C). Due to its hygroscopic nature, the container must be kept tightly sealed after opening to prevent moisture absorption, which can affect stability and potency.

Specification

Item	Specification
Appearance	Off-white to light yellow, crystalline powder
Identification (IR)	Conforms to reference standard
Assay (HPLC)	98.0% - 102.0% (on anhydrous basis)
Related Substances (HPLC)	Total impurities ≤ 2.0%
Loss on Drying	≤ 1.0%
Residue on Ignition	≤ 0.1%
Heavy Metals	≤ 20 ppm

Note: Specifications can be tailored. Please contact us for the detailed technical data sheet of a specific grade.