Istaroxime HCl is a Na+/K+-ATPase inhibitor (IC50=0.11 μM) and sarcoplasmic/endoplasmic reticulum calcium ATPase 2 (SERCA 2) activator.

Physicochemical Properties

Molecular Formula	C21H33CLN2O3
Molecular Weight	396.956
Exact Mass	396.218
CAS #	374559-48-5
Related CAS #	Istaroxime;203737-93-3
PubChem CID	72941813
Appearance	White to light brown solid powder
LogP	4.61
Hydrogen Bond Donor Count	2
Hydrogen Bond Acceptor Count	5
Rotatable Bond Count	3
Heavy Atom Count	27
Complexity	645
Defined Atom Stereocenter Count	6
SMILES	C[C@]12CCC(=NOCCN)C[C@@H]1C(=O)C[C@@H]3[C@@H]2CC[C@]4([C@H]3CCC4=O)C.Cl
InChi Key	AXHJYJDJXNOGNI-DESZRGPQSA-N
InChi Code	InChI=1S/C21H32N2O3.ClH/c1-20-7-5-13(23-26-10-9-22)11-17(20)18(24)12-14-15-3-4-19(25)21(15,2)8-6-16(14)20;/h14-17H,3-12,22H2,1-2H3;1H/t14-,15-,16-,17+,20+,21-;/m0./s1
Chemical Name	(5S,8R,9S,10R,13S,14S)-3-(2-aminoethoxyimino)-10,13-dimethyl-1,2,4,5,7,8,9,11,12,14,15,16-dodecahydrocyclopenta[a]phenanthrene-6,17-dione;hydrochloride
Synonyms	PST2744 HCl; Istaroxime
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 Note: Please store this product in a sealed and protected environment, avoid exposure to moisture.
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	Na+, K+-ATPase is regulated by isostaroxime hydrochronous, a positive inotropic substance. With an IC50 value of 0.43±0.15 μM, istaxime hydrochloride (PST2744) modifies the Na+/K+-ATPase activity in pH solution[2]. Microorganisms with Na+/K+-ATPase activity had an efficacious concentration of 8.5 μM for PST2744 [3].
ln Vivo	Istaxime hydrochloride (PST2744) generates a steady increase in +dP/dtmax during the infusion, reaching 80% (ED80) at a dose (EDmax) of 4.88 ± 0.6 mg/kg and 80% (ED80) at a dose (EDmax) of 4.88 ± 0.6 mg/kg. At 0.6 mg/kg, the maximum is 140±3.5%[3].
References	[1]. Novel analogues of istaroxime, a potent inhibitor of Na+,K+-ATPase: synthesis and structure-activity relationship. J Med Chem. 2008 Aug 14;51(15):4601-8. [2]. Novel analogues of Istaroxime, a potent inhibitor of Na(+),K(+)-ATPase: Synthesis, structure-activity relationship and 3D-quantitative structure-activity relationship of derivatives at position 6 on the androstane scaffold. Bioorg Med Ch. [3]. Pharmacological profile of the novel inotropic agent (E,Z)-3-((2-aminoethoxy)imino)androstane-6,17-dione hydrochloride (PST2744). J Pharmacol Exp Ther. 2002 Nov;303(2):592-600.

Solubility Data

Solubility (In Vitro)

DMSO : ≥ 45 mg/mL (~113.36 mM) H2O : ~25 mg/mL (~62.98 mM)

Solubility (In Vivo)

Solubility in Formulation 1: ≥ 2.5 mg/mL (6.30 mM) (saturation unknown) in 10% DMSO + 40% PEG300 + 5% Tween80 + 45% Saline (add these co-solvents sequentially from left to right, and one by one), clear solution. For example, if 1 mL of working solution is to be prepared, you can add 100 μL of 25.0 mg/mL clear DMSO stock solution to 400 μL PEG300 and mix evenly; then add 50 μL Tween-80 to the above solution and mix evenly; then add 450 μL normal saline to adjust the volume to 1 mL. Preparation of saline: Dissolve 0.9 g of sodium chloride in 100 mL ddH₂ O to obtain a clear solution. Solubility in Formulation 2: ≥ 2.5 mg/mL (6.30 mM) (saturation unknown) in 10% DMSO + 90% (20% SBE-β-CD in Saline) (add these co-solvents sequentially from left to right, and one by one), clear solution. For example, if 1 mL of working solution is to be prepared, you can add 100 μL of 25.0 mg/mL clear DMSO stock solution to 900 μL of 20% SBE-β-CD physiological saline solution and mix evenly. 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. Solubility in Formulation 3: ≥ 2.5 mg/mL (6.30 mM) (saturation unknown) in 10% DMSO + 90% Corn Oil (add these co-solvents sequentially from left to right, and one by one), clear solution. For example, if 1 mL of working solution is to be prepared, you can add 100 μL of 25.0 mg/mL clear DMSO stock solution to 900 μL of corn oil and mix evenly. Solubility in Formulation 4: 12.5 mg/mL (31.49 mM) in PBS (add these co-solvents sequentially from left to right, and one by one), clear solution; with ultrasonication (<60°C).  (Please use freshly prepared in vivo formulations for optimal results.)

Preparing Stock Solutions		1 mg	5 mg	10 mg
	1 mM	2.5191 mL	12.5957 mL	25.1915 mL
	5 mM	0.5038 mL	2.5191 mL	5.0383 mL
	10 mM	0.2519 mL	1.2596 mL	2.5191 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.