Name: L-Thyroxine (Levothyroxine)
Brand: Selleck Chemicals
SKU: S2599
Availability: InStock
Rating: 5 (3 reviews)

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Quality Control

Batch: Purity: 99.26%

99.26

Related Targets	Dehydrogenase HSP Transferase P450 (e.g. CYP17) PDE phosphatase PPAR Vitamin Carbohydrate Metabolism Mitochondrial Metabolism
Other THR Inhibitors	MGL-3196 (Resmetirom) L-Thyroxine sodium salt pentahydrate TI17 dextrothyroxine sodium Eprotirome (KB2115) Tiratricol ALG-055009

Solubility

In vitro
Batch:

DMSO : 100 mg/mL (128.72 mM)
(Moisture-contaminated DMSO may reduce solubility. Use fresh, anhydrous DMSO.)

Water : Insoluble

Ethanol : Insoluble

Molarity Calculator

Mass	Concentration	Volume	Molecular Weight
Mass value Mass unit	Concentration value Concentration unit	Volume value Volume unit	Molecular weight (g/mol)

Dilution Calculator Molecular Weight Calculator

In vivo batch selection In vivo Batch:
Homogeneous suspension	CMC-NA	≥5mg/ml	Taking the 1 mL working solution as an example, add 5 mg of this product to 1 ml of CMC-Na solution, mix evenly to obtain a homogeneous suspension with a final concentration of 5 mg/ml.
Clear solution	5%DMSO 1 40%PEG300 2 5%Tween80 3 50%ddH2O Validated by Selleck labs. Should you need adjustments to this formulation, contact our sales team for custom testing.	5.000mg/ml (6.44mM)	Taking the 1 mL working solution as an example, add 50 μL of 100 mg/ml clarified DMSO stock solution to 400 μL of PEG300, mix evenly to clarify it; add 50 μL of Tween80 to the above system, mix evenly to clarify; then continue to add 500 μL of ddH2O to adjust the volume to 1 mL. The mixed solution should be used immediately for optimal results.
Clear solution	5% DMSO 1 95% Corn oil Validated by Selleck labs. Should you need adjustments to this formulation, contact our sales team for custom testing.	0.625mg/ml (0.80mM)	Taking the 1 mL working solution as an example, add 50 μL of 12.5 mg/ml clear DMSO stock solution to 950 μL of corn oil and mix evenly. The mixed solution should be used immediately for optimal results.
Homogeneous suspension	CMC-NA	≥5mg/ml	Taking the 1 mL working solution as an example, add 5 mg of this product to 1 ml of CMC-Na solution, mix evenly to obtain a homogeneous suspension with a final concentration of 5 mg/ml.
Homogeneous suspension	CMC-NA	≥5mg/ml	Taking the 1 mL working solution as an example, add 5 mg of this product to 1 ml of CMC-Na solution, mix evenly to obtain a homogeneous suspension with a final concentration of 5 mg/ml.

In vivo Formulation Calculator (Clear solution)

Step 1: Enter information below (Recommended: An additional animal making an allowance for loss during the experiment)

Dosage: mg/kg

Average weight of animals: g

Dosing volume per animal: μL

Number of animals:

Step 2: Enter the in vivo formulation (This is only the calculator, not formulation. Please contact us first if there is no in vivo formulation at the solubility Section.)

% DMSO

%

% Tween 80

% ddH₂O

% DMSO

+

%

Calculation results:

Working concentration: mg/ml;

Method for preparing DMSO master liquid: mg drug pre-dissolved in μL DMSO ( Master liquid concentration mg/mL, Please contact us first if the concentration exceeds the DMSO solubility of the batch of drug. )

Method for preparing in vivo formulation: Take μL DMSO master liquid, next addμL PEG300, mix and clarify, next addμL Tween 80, mix and clarify, next add μL ddH₂O, mix and clarify.

Method for preparing in vivo formulation: Take μL DMSO master liquid, next add μL Corn oil, mix and clarify.

Note: 1. Please make sure the liquid is clear before adding the next solvent.
2. Be sure to add the solvent(s) in order. You must ensure that the solution obtained, in the previous addition, is a clear solution before proceeding to add the next solvent. Physical methods such
as vortex, ultrasound or hot water bath can be used to aid dissolving.

Chemical Information, Storage & Stability

Molecular Weight	776.87	Formula	C₁₅H₁₁I₄NO₄	Storage (From the date of receipt)	3 years-20°Cpowder
CAS No.	51-48-9	Download SDF		Storage of Stock Solutions	1 year-80°Cin solvent 1 month-20°Cin solvent
Synonyms	NSC 36397			SMILES	C1=C(C=C(C(=C1I)OC2=CC(=C(C(=C2)I)O)I)I)CC(C(=O)O)N

Read more about storage stability stock solution CAS number SMILES

Mechanism of Action

Clinical Trial Information

(data from https://clinicaltrials.gov, updated on 2026-02-06)

NCT Number	Recruitment	Conditions	Sponsor/Collaborators	Start Date	Phases
NCT07393165	RECRUITING	Levothyroxine; Cardiac Function; Children; Subclinical Hypothyroidism	Tanta University	2025-05-24
NCT06660823	COMPLETED	Cardiac Surgery Intensive Care Treatment; Delayed Recovery From Anaesthesia; Euthyroid Sick Syndrome; Cardiac Surgery Requiring Cardiopulmonary Bypass	Ain Shams University	2024-11-30	PHASE3
NCT06096454	Not yet recruiting	Hypothyroidism\|Insulin Resistance	Assiut University	2023-11-20	Phase 4
NCT01848171	UNKNOWN	Hypothyroidism; Thyroid Diseases; Endocrine System Diseases	Shandong Provincial Hospital	2013-07	PHASE4
NCT05918497	Active not recruiting	Different Regimens in Treatment of Hypothyroidism During Fasting in Ramadan	Sohag University	2023-04-25	--
NCT05646420	Completed	Autosomal Dominant Polycystic Kidney	Mario Negri Institute for Pharmacological Research	2023-02-01	Not Applicable

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Handling Instructions

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L-Thyroxine (Levothyroxine) THR chemical

Chemical Structure

Molecular Weight: 776.87