Atrasentan hydrochloride

Storage conditions: Under inert gas (nitrogen or argon) at 2-8°C

Solubility: Soluble in dimethyl sulfoxide

Form: Powder

Color: Off-white to Gray

1. Cell Experiment

Solubility in DMSO: 28.57 mg/mL (52.22 mM; ultrasonic dissolution required; hygroscopic DMSO significantly affects product solubility, use newly opened DMSO)

Solubility in H₂O: 0.5 mg/mL (0.91 mM; requires ultrasonication, warming, pH adjustment to 4 with HCl, and heating to 60°C)

Solubility in 0.1 M HCl: <1 mg/mL (insoluble)

Preparing Stock Solutions：

Select an appropriate solvent for stock solution preparation based on the solubility of the product in different solvents. Once dissolved, aliquot and store to avoid product failure caused by repeated freeze-thaw cycles.

Storage conditions and duration of stock solution: -80°C for 6 months; -20°C for 1 month (sealed storage, protected from moisture). When stored at -80°C, use within 6 months; when stored at -20°C, use within 1 month.

Note: If water is selected as the solvent for the stock solution, dilute to the working concentration and sterilize by filtration through a 0.22 μm filter before use.

2. Animal Experiment

Please select an appropriate dissolution scheme based on your experimental animals and route of administration.

The following dissolution schemes all require first preparing a clear stock solution according to the In Vitro method, followed by sequential addition of cosolvents:

—To ensure the reliability of experimental results, the clear stock solution can be stored appropriately according to the storage conditions. For in vivo working solutions, it is recommended to prepare them fresh on the day of use.

The percentages indicated for the following solvents refer to their volume proportion in the final solution. If precipitation or crystallization occurs during preparation, dissolution can be assisted by heating and/or sonication.

Scheme 1

Add each solvent in sequence: 10% DMSO, 40% PEG300, 5% Tween-80, 45% Saline

Solubility: ≥ 2.5 mg/mL (4.57 mM); clear solution

This scheme yields a clear solution of ≥ 2.5 mg/mL (saturation unknown).

For example, to prepare 1 mL of working solution: add 100 μL of a 25.0 mg/mL clear DMSO stock solution to 400 μL of PEG300 and mix well; then add 50 μL of Tween-80 to the system and mix well; finally, add 450 μL of saline to bring the volume to 1 mL.

Preparation of saline: Dissolve 0.9 g of sodium chloride in ddH₂O and bring the volume to 100 mL to obtain a clear saline solution.

Scheme 2

Add each solvent in sequence: 10% DMSO, 90% (20% SBE-β-CD in Saline)

Solubility: ≥ 2.5 mg/mL (4.57 mM); clear solution

This scheme yields a clear solution of ≥ 2.5 mg/mL (saturation unknown).

For example, to prepare 1 mL of working solution: add 100 μL of a 25.0 mg/mL clear DMSO stock solution to 900 μL of 20% SBE-β-CD in saline and mix well.

Dissolve 2 g of SBE-β-CD (sulfobutylether β-cyclodextrin) powder in saline and bring the volume to 10 mL until fully dissolved to a clear solution.

Scheme 3

Add each solvent in sequence: 10% DMSO, 90% Corn Oil

Solubility: ≥ 2.5 mg/mL (4.57 mM); clear solution

This scheme yields a clear solution of ≥ 2.5 mg/mL (saturation unknown). Use this scheme with discretion for animal studies lasting longer than half a month.

For example, to prepare 1 mL of working solution: add 100 μL of a 25.0 mg/mL clear DMSO stock solution to 900 μL of corn oil and mix well.

For the following dissolution schemes, prepare the working solution directly. It is recommended to prepare fresh and use as soon as possible within a short period. The percentages indicated for the following solvents refer to their volume proportion in the final solution. If precipitation or crystallization occurs during preparation, dissolution can be assisted by heating and/or sonication.

Scheme 1

Add each solvent in sequence: 0.5% CMC-Na/saline water

Solubility: 0.75 mg/mL (1.37 mM); clear solution; ultrasonic heating assisted dissolution.

Atrasentan exerts its therapeutic effects via antagonism of endothelin receptors. It is significantly (>1800-fold) more selective for endothelin A receptors (Ki = 0.034 nM) than endothelin B receptors (Ki = 63.3 nM).

The pathogenesis of IgA nephropathy begins with abnormal O-glycosylation of IgA, leading to increased levels of galactose-deficient IgA. The immune system then produces autoantibodies against these altered IgA molecules, forming circulating immune complexes. These complexes deposit in the kidney's mesangium, triggering mesangial cell activation, complement system involvement, and the release of inflammatory cytokines, leading to inflammation, protein deposition, and fibrosis within the kidneys. Amongst other downstream effects, the inflammation caused by immune complex deposition causes an upregulation in endothelin-1 (ET-1), which binds to endothelin A receptors (ETAR) on renal cells. The activation of ETAR has been implicated in podocyte damage, proteinuria, fibrosis, and further progression of kidney disease. Atrasentan is a selective antagonist of ETAR, preventing the binding of ET-1 and thereby reducing the associated detrimental downstream effects.