MK-571 (L-660711) is a novel, potent, selective, orally bioactive antagonist of leukotriene D4 (LTD4) receptor with Kis of 0.22 and 2.1 nM in guinea pig and human lung membranes. MK-571 blocks the binding of LTD4, but not LTC4, to human and guinea pig lung membranes with Ki values of 0.22 nM and 2.1 nM, respectively. MK-571 attenuates kidney ischemia and reperfusion-induced airway hypersensitivity in rats. MK-571 alters bronchoalveolar lavage fluid proteome in a mouse asthma model.

Physicochemical Properties

Molecular Formula	C26H27CLN2O3S2
Molecular Weight	537.06904
Exact Mass	514.115
CAS #	115104-28-4
Related CAS #	MK-571 sodium;115103-85-0
PubChem CID	5281888
Appearance	Off-white to light yellow solid powder
Density	1.3±0.1 g/cm3
Boiling Point	712.3±60.0 °C at 760 mmHg
Flash Point	384.6±32.9 °C
Vapour Pressure	0.0±2.4 mmHg at 25°C
Index of Refraction	1.687
LogP	5.93
Hydrogen Bond Donor Count	1
Hydrogen Bond Acceptor Count	6
Rotatable Bond Count	11
Heavy Atom Count	34
Complexity	693
Defined Atom Stereocenter Count	0
SMILES	O=C(O)CCSC(C1=CC=CC(/C=C/C2=NC3=CC(Cl)=CC=C3C=C2)=C1)SCCC(N(C)C)=O
HS Tariff Code	2934.99.9001
Storage	Powder-20°C 3 years 4°C 2 years In solvent -80°C 6 months -20°C 1 month
Shipping Condition	Room temperature (This product is stable at ambient temperature for a few days during ordinary shipping and time spent in Customs)

Biological Activity

ln Vitro	MK571 (15 μM, 1 hour) strongly suppresses Fluo-3 efflux as well as constitutive and Ag-stimulated S1P in RBL-2H3 cells and mast cells [3].
ln Vivo	MK-571 (0-0.5 mg/kg once, lateral) induces a dose-dependent decrease of the duration of dyspnea induced at light-sensitizing doses in individuals treated with methysergide (3 μg/kg) [1]. MK-571 (0-1 mg/kg, wall, once) causes modest 4- and Ascaris-induced fold contractions in awake squirrel monkeys [1]. MK-571 (0-25 mg/kg, wall, daily, for more than 2 weeks) cures hypoxic pulmonary hypertension (PH) and protects the chest of mice against the effects of hypoxia PH [2].
Cell Assay	Cell Viability Assay[3] Cell Types: RBL- 2H3 cells, human LAD2 mast cells Tested Concentrations: 15 μM Incubation Duration: 1 h Experimental Results: RBL-2H3 cells transfected with vector and SphK1 inhibited S1P secretion, but did not affect [3H]Sph uptake and intracellular conversion to S1P. Inhibits Fluo-3 efflux, inhibits S1P export from LAD2 cells, and prevents Ag-stimulated S1P release.
Animal Protocol	Animal/Disease Models: hyperresponsive rats (200-400 g of each male and female, pre-treatment with intravenous (iv) (iv)injection of 3 μg/kg methysergide, 5 minutes before antigen extraction) [1] Doses: 0.5, 0.15 and 0.05 mg/kg Route of Administration: po (po (oral gavage)) once, 1 or 4 hrs (hrs (hours)) before challenge Experimental Results: Dose-dependent suppression of antigen duration-induced dyspnea with ED50 values of 0.13 (95% confidence interval (CI), 0.03-0.62) and 0.11 (95% CI, 0.009-1.47) mg/kg. MK-571 was more active when administered orally as a 1% Methocel suspension (4 hrs (hrs (hours)) pretreatment), with an ED50 of 0.068 (95% CI, 0.83-0.14) mg/kg. Animal/Disease Models: Csnscisus squirrel msnkeys[1] Doses: 0.1, 0.5 and 1 mg/kg Route of Administration: Oral once 2 hrs (hrs (hours)) before Ascaris antigen challenge Experimental Results: 0.5 mg/kg produced significant inhibition of bronchoconstriction, produced significant inhibition 1 mg/kg inhibits the increase of RL and the decrease of Cdyn. Animal/Disease Models: FVB (Friend virus type B) mice (Mrp4–/– and WT, 6 weeks old, exposed to chr
References	[1]. Pharmacology of L-660,711 (MK-571): a novel potent and selective leukotriene D4 receptor antagonist. Can J Physiol Pharmacol. 1989 Jan;67(1):17-28. [2]. Inhibition of MRP4 prevents and reverses pulmonary hypertension in mice. J Clin Invest. 2011 Jul;121(7):2888-97. [3]. Role of ABCC1 in export of sphingosine-1-phosphate from mast cells. Proc Natl Acad Sci U S A. 2006 Oct 31;103(44):16394-9.
Additional Infomation	MK 571 is a member of quinolines.

Solubility Data

Solubility (In Vitro)

May dissolve in DMSO (in most cases), if not, try other solvents such as H2O, Ethanol, or DMF with a minute amount of products to avoid loss of samples

Solubility (In Vivo)

Note: Listed below are some common formulations that may be used to formulate products with low water solubility (e.g. < 1 mg/mL), you may test these formulations using a minute amount of products to avoid loss of samples. Injection Formulations (e.g. IP/IV/IM/SC) Injection Formulation 1: DMSO : Tween 80： Saline = 10 : 5 : 85 (i.e. 100 μL DMSO stock solution → 50 μL Tween 80 → 850 μL Saline) *Preparation of saline: Dissolve 0.9 g of sodium chloride in 100 mL ddH ₂ O to obtain a clear solution. Injection Formulation 2: DMSO : PEG300 ：Tween 80 : Saline = 10 : 40 : 5 : 45 (i.e. 100 μL DMSO → 400 μLPEG300 → 50 μL Tween 80 → 450 μL Saline) Injection Formulation 3: DMSO : Corn oil = 10 : 90 (i.e. 100 μL DMSO → 900 μL Corn oil) Example: Take the Injection Formulation 3 (DMSO : Corn oil = 10 : 90) as an example, if 1 mL of 2.5 mg/mL working solution is to be prepared, you can take 100 μL 25 mg/mL DMSO stock solution and add to 900 μL corn oil, mix well to obtain a clear or suspension solution (2.5 mg/mL, ready for use in animals). Injection Formulation 4: DMSO : 20% SBE-β-CD in saline = 10 : 90 [i.e. 100 μL DMSO → 900 μL (20% SBE-β-CD in saline)] *Preparation of 20% SBE-β-CD in Saline (4°C，1 week): Dissolve 2 g SBE-β-CD in 10 mL saline to obtain a clear solution. Injection Formulation 5: 2-Hydroxypropyl-β-cyclodextrin : Saline = 50 : 50 (i.e. 500 μL 2-Hydroxypropyl-β-cyclodextrin → 500 μL Saline) Injection Formulation 6: DMSO : PEG300 : castor oil : Saline = 5 : 10 : 20 : 65 (i.e. 50 μL DMSO → 100 μLPEG300 → 200 μL castor oil → 650 μL Saline) Injection Formulation 7: Ethanol : Cremophor : Saline = 10： 10 : 80 (i.e. 100 μL Ethanol → 100 μL Cremophor → 800 μL Saline) Injection Formulation 8: Dissolve in Cremophor/Ethanol (50 : 50), then diluted by Saline Injection Formulation 9: EtOH : Corn oil = 10 : 90 (i.e. 100 μL EtOH → 900 μL Corn oil) Injection Formulation 10: EtOH : PEG300：Tween 80 : Saline = 10 : 40 : 5 : 45 (i.e. 100 μL EtOH → 400 μLPEG300 → 50 μL Tween 80 → 450 μL Saline) Oral Formulations Oral Formulation 1: Suspend in 0.5% CMC Na (carboxymethylcellulose sodium) Oral Formulation 2: Suspend in 0.5% Carboxymethyl cellulose Example: Take the Oral Formulation 1 (Suspend in 0.5% CMC Na) as an example, if 100 mL of 2.5 mg/mL working solution is to be prepared, you can first prepare 0.5% CMC Na solution by measuring 0.5 g CMC Na and dissolve it in 100 mL ddH2O to obtain a clear solution; then add 250 mg of the product to 100 mL 0.5% CMC Na solution, to make the suspension solution (2.5 mg/mL, ready for use in animals). Oral Formulation 3: Dissolved in PEG400 Oral Formulation 4: Suspend in 0.2% Carboxymethyl cellulose Oral Formulation 5: Dissolve in 0.25% Tween 80 and 0.5% Carboxymethyl cellulose Oral Formulation 6: Mixing with food powders Note: Please be aware that the above formulations are for reference only. InvivoChem strongly recommends customers to read literature methods/protocols carefully before determining which formulation you should use for in vivo studies, as different compounds have different solubility properties and have to be formulated differently.  (Please use freshly prepared in vivo formulations for optimal results.)

Preparing Stock Solutions		1 mg	5 mg	10 mg
	1 mM	1.8620 mL	9.3098 mL	18.6195 mL
	5 mM	0.3724 mL	1.8620 mL	3.7239 mL
	10 mM	0.1862 mL	0.9310 mL	1.8620 mL

*Note: Please select an appropriate solvent for the preparation of stock solution based on your experiment needs. For most products, DMSO can be used for preparing stock solutions (e.g. 5 mM, 10 mM, or 20 mM concentration); some products with high aqueous solubility may be dissolved in water directly. Solubility information is available at the above Solubility Data section. Once the stock solution is prepared, aliquot it to routine usage volumes and store at -20°C or -80°C. Avoid repeated freeze and thaw cycles.