Catalog No.S6749

For research use only.

ASP-9521 is a selective, orally bioavailable inhibitor of 17beta-hydroxysteroid dehydrogenase type 5 (17β-HSD5).

ASP-9521 Chemical Structure

CAS No. 1126084-37-4

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Biological Activity

Description ASP-9521 is a selective, orally bioavailable inhibitor of 17beta-hydroxysteroid dehydrogenase type 5 (17β-HSD5).
17β-HSD5 [1]
In vitro

In vitro, ASP9521 inhibited the conversion of androstenedione into testosterone by recombinant human and cynomolgus monkey AKR1C3 in a concentration-dependent manner, with IC50 values of 11 and 49 nmol/L, respectively. In contrast, ASP9521 did not inhibit the conversion by rat and mouse homologues (AKR1C1 and AKR1C6, respectively) up to a concentration of 10 μmol/L. ASP9521 showed moderately high selectivity (>100-fold) for human AKR1C3 (IC50: 120 nmol/L) over the human isoform AKR1C2 (IC50: >20,000 nmol/L)[1].

In vivo

In murine models harbouring CWR22R xenograft tumours, single oral administration of ASP9521 suppressed AD-induced intratumoural testosterone production in a dose-dependent manner. This inhibitory effect was maintained for 24 h after single oral administration of ASP9521. Over this 24 h period, ASP9521 concentration rapidly decreased in plasma from 771.8 ng/mL (mean) to undetectable levels, while its intratumoural concentration reached its maximal level within 15 min after administration of ASP9521 and remained stable for 24 h. In nude mice bearing HEK293 tumours with or without AKR1C3 expression, after single oral administration of ASP9521, plasma concentrations of ASP9521 reached maximum values within 0.25 h (mean: 767.3 ng/mL and 648.2 ng/mL for HEK293 and HEK293-AKR1C3 cells, respectively), but decreased rapidly thereafter. Accumulation of ASP9521 in tumour tissue may depend on AKR1C3 expression. After single oral administration of 1 mg/kg ASP9521 to rats, dogs and monkeys, the drug was rapidly absorbed. The bioavailability values were 35 %, 78 %, and 58 %, respectively. After iv administration of ASP9521 to rats, dogs and monkeys, plasma concentrations of the drug declined with t1/2 values of 0.2, 1.7 and 5.8 h, respectively[1].

Protocol (from reference)

Cell Research:


  • Cell lines: LNCaP-AKR1C3 cells stably expressing human AKR1C3
  • Concentrations: 0.3-100 nmol/L
  • Incubation Time: 24 h or 6 days
  • Method:

    LNCaP-AKR1C3 cells stably expressing human AKR1C3 were seeded in 96-well plates at 1x 104 cells/100 μL/well in RPMI-1640 medium supplemented with heat-inactivated charcoal-dextran-stripped FBS (1 % for the PSA expression assay and T measurement and 5 % for the cell proliferation assay). After 24 h incubation, AD was added to each well with or without ASP9521 (0.3-100 nmol/L). The cell culture media were collected 24 h after administration of AD to measure T concentration and 6 days after administration of AD to measure either PSA levels or cell proliferation.

  • (Only for Reference)
Animal Research:


  • Animal Models: Male Balb/c athymic nude mice (4-6 weeks old) with CWR22R tumours
  • Dosages: 1, 3 or 10 mg/kg
  • Administration: oral administration
  • (Only for Reference)

Solubility (25°C)

In vitro

DMSO 66 mg/mL
(199.74 mM)
Ethanol 66 mg/mL
(199.74 mM)
Water Insoluble

* Please note that Selleck tests the solubility of all compounds in-house, and the actual solubility may differ slightly from published values. This is normal and is due to slight batch-to-batch variations.

Chemical Information

Molecular Weight 330.42


CAS No. 1126084-37-4
Storage 3 years -20°C powder
2 years -80°C in solvent
Smiles CC(C)(CC1CCN(CC1)C(=O)C2=CC3=C(N2)C=CC(=C3)OC)O

In vivo Formulation Calculator (Clear solution)

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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.

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Tech Support

Answers to questions you may have can be found in the inhibitor handling instructions. Topics include how to prepare stock solutions, how to store inhibitors, and issues that need special attention for cell-based assays and animal experiments.

Handling Instructions

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