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Losmapimod p38 MAPK inhibitor

Name: Losmapimod
Brand: Selleck Chemicals
SKU: S7215
Availability: InStock
Rating: 5 (26 reviews)

Cat.No.S7215

Losmapimod is a selective, potent, and orally active p38 MAPK inhibitor with pK_i of 8.1 and 7.6 for p38α and p38β, respectively. P38 MAPKs are involved in cell differentiation, apoptosis and autophagy. Phase 3.

Chemical Structure

Molecular Weight: 383.46

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Quality Control

Batch: Purity: 99.98%

99.98

Related Targets	ERK Raf JNK MEK Ras KRas S6 Kinase MAP4K TAK1 Mixed Lineage Kinase
Other p38 MAPK Inhibitors	SB202190 SB203580 (Adezmapimod) PH-797804 Doramapimod (BIRB 796) Ralimetinib (LY2228820) dimesylate VX-702 SB239063 Asiatic Acid Neflamapimod (VX-745) BMS-582949

Cell Culture, Treatment & Working Concentration

Cell Lines	Assay Type	Concentration	Incubation Time	Formulation	Activity Description	PMID
PBMC	Function assay		1 h		Inhibition of p38alpha-dependent TNFalpha production in human PBMC preincubated for 1 hr before LPS challenge by ELISA, IC50=0.1 μM	19772287
Click to View More Cell Line Experimental Data

Solubility

In vitro
Batch:

DMSO : 76 mg/mL (198.19 mM)
(Moisture-contaminated DMSO may reduce solubility. Use fresh, anhydrous DMSO.)

Ethanol : 76 mg/mL

Water : 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.
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	383.46	Formula	C₂₂ H₂₆ F N₃ O₂	Storage (From the date of receipt)	3 years-20°Cpowder
CAS No.	585543-15-3	Download SDF		Storage of Stock Solutions	1 year-80°Cin solvent 1 month-20°Cin solvent
Synonyms	GW856553X, GSK-AHAB			SMILES	CC1=C(C=C(C=C1F)C(=O)NC2CC2)C3=NC=C(C=C3)C(=O)NCC(C)(C)C

Read more about storage stability stock solution CAS number SMILES

Mechanism of Action

Targets/IC₅₀/Ki	p38α (Cell-free assay) 8.1(pKi) p38β (Cell-free assay) 7.6(pKi)
In vitro	Losmapimod (GW856553X, GW856553, GSK-AHAB) is a selective, potent, and orally active p38 MAPK inhibitor.
Kinase Assay	In vitro assay
Kinase Assay	Inhibition of p38α and p38β are determined by use of a ligand-displacement fluorescence polarization assay.
In vivo	In spontaneously hypertensive stroke-prone rats (SHR-SP), Losmapimod significantly improves survival, endothelial-dependent and -independent vascular relaxation, and indices of renal function, and subsequently attenuates dyslipidemia, hypertension, cardiac remodeling, plasma renin activity (PRA), aldosterone, and interleukin-1beta (IL-1beta).
References	[1] https://pubmed.ncbi.nlm.nih.gov/19556450/ [2] https://pubmed.ncbi.nlm.nih.gov/36196640/

Clinical Trial Information

(data from https://clinicaltrials.gov, updated on 2025-11-10)

NCT Number	Recruitment	Conditions	Sponsor/Collaborators	Start Date	Phases
NCT05397470	TERMINATED	Facioscapulohumeral Muscular Dystrophy (FSHD)	Fulcrum Therapeutics	2022-06-16	PHASE3
NCT04264442	TERMINATED	Facioscapulohumeral Muscular Dystrophy (FSHD)	Fulcrum Therapeutics	2020-02-13	PHASE2
NCT04004000	TERMINATED	Facioscapulohumeral Muscular Dystrophy 1	Fulcrum Therapeutics	2019-08-23	PHASE2
NCT05002231	COMPLETED	Healthy Adult Subjects	Fulcrum Therapeutics	2021-08-19	PHASE1
NCT04511819	TERMINATED	COVID-19	Fulcrum Therapeutics	2020-08-28	PHASE3
NCT04003974	COMPLETED	Facioscapulohumeral Muscular Dystrophy (FSHD)	Fulcrum Therapeutics	2019-08-09	PHASE2

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