Sildenafil Citrate

For research use only.

Catalog No.S1431

15 publications

Sildenafil Citrate Chemical Structure

CAS No. 171599-83-0

Sildenafil Citrate, a selective inhibitor of cyclic guanosine monophosphate (cGMP)-specific phosphodiesterase type 5 (PDE5), is a well-tolerated and highly effective treatment for erectile dysfunction.

Selleck's Sildenafil Citrate has been cited by 15 publications

3 Customer Reviews

  • T24 cells were treated with vehicle, SIL (2 uM), DOX (200 nM) as indicated. Cells were isolated 6 and 12 hours after exposure, and the phosphorylation of γH2AX was determined, with the fold increase in phosphorylation shown.

    Mol Pharmacol 2014 5(3), 408-19. Sildenafil Citrate purchased from Selleck.

  • BT549 and HOSS1 cells in 96 well plates were treated with celecoxib (CEL 5.0 uM) and/or sildenafil (SIL, 2.0 uM). Six h after treatment cells were fixed to the plate and immunohistochemistry performed to determine the plasma membrane levels of CD95. The upper images obtained using the Hermes Wiscan imaging system is representative of the data. The intensity of CD95 immunostaining was determined using the Wisoft data analysis package (n = 3 +/- SEM). * p < 0.05 value greater than celecoxib treatment alone.

    J Cell Physiol 2014 10.1002/jcp.24843. Sildenafil Citrate purchased from Selleck.

  • ADOR lung cancer cells (a July 2015 PDX model) were transfected with an empty vector plasmid or plasmids to express GRP78 and HSP27 together. Twenty-four hours after transfection cells were treated with vehicle control or with OSU-03012 (2.0mM) sildenafil (2mM) for 6 h after which cells were fixed in place and permeabilized using 0.5% Triton X100. Immuno-fluorescence was performed to detect the expression levels of Calnexin; glucosidase I; and glucosidase IIa at 10 magnification using a Hermes WiScan system.

    J Cell Physiol, 2016, 231(10):2286-302. . Sildenafil Citrate purchased from Selleck.

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Biological Activity

Description Sildenafil Citrate, a selective inhibitor of cyclic guanosine monophosphate (cGMP)-specific phosphodiesterase type 5 (PDE5), is a well-tolerated and highly effective treatment for erectile dysfunction.
PDE5 [1]
(Cell-free assay)
PDE6 [1]
(Cell-free assay)
3.5 nM 33 nM
In vitro

Sildenafil citrate is a potent PDE type 5 reversible and selective inhibitor that blocks cGMP hydrolysis effectively (Ki ∼3 nM). Sildenafil exhibited high affinity for PDE type 5 and type 6 with inhibition constants (Ki) of ∼3.5 and 33 nM, respectively. Sildenafil enhances sodium nitroprusside- or transmural electrical stimulation-induced relaxation of precontracted corpus cavernosum muscle strips in organ baths, suggesting that sildenafil augments the activity of NO-mediated relaxation. Sildenafil citrate increases intracellular cGMP concentrations in cultured smooth muscle cells treated with sodium nitroprusside and in rabbit corpus cavernosum in vitro. Sildenafil is metabolized in the liver by cytochrome P450 and is converted into an active metabolite with characteristics similar to the parent compound. [1]

Methods Test Index PMID
Western blot
HIF-1α / HIF-2α ; 

PubMed: 23065129     

Sildenafil up-regulated HIF-1α and HIF-2α in a dose-dependent manner. Human small airway epithelial (HSAEp-C) cells were incubated with the indicated concentrations of sildenafil for 16 hours, and the expression of HIF-1/2α was evaluated by Western blotting. 

VEGF / PDK1 / CA9 ; 

PubMed: 23065129     

Semiquantitative RT-PCR of HIF-target gene transcripts in HSAEp-C cells. Cells were incubated with 100 μM sildenafil for the indicated times, and total RNAs were extracted. The mRNA concentrations of VEGF, pyruvate dehydrogenase kinase (PDK), carbonic anhydrase 9 (CA9), and HIF-1α were analyzed by RT-PCR with deoxycytidine 5′-[α-32P] triphosphate and autoradiographed. The result is representative of three experiments.

p-AKT / AKT / p-mTOR / mTOR ; 

PubMed: 23065129     

Sildenafil activated the AKT/mTOR signaling pathway. HSAEp-C cells were incubated with 100 μM sildenafil for the indicated times, and then harvested to determine protein concentrations by Western blotting. 

In vivo Sildenafil citrate enhances erectile function following pelvic nerve stimulation in anesthetized dogs as measured by increased intracavernosal pressure. [1] Sildenafil citrate significantly reverses impaired carbachol-stimulated relaxation and inhibits superoxide formation by cavernosal tissue from hypercholesterolaemic rabbits. [2] Sildenafil improves erectile function in a time- and dose-dependent fashion with maximization of erectile function recovery occurring with daily 20 mg/kg at the 28-day time point in Sprague-Dawley rats. Sildenafil use results in smooth muscle-collagen ratio protection and CD31 and eNOS expression preservation in Sprague-Dawley rats. Sildenafil reduces apoptotic indices significantly compared with control, and increases phosphorylation of akt and eNOS in Sprague-Dawley rats. [3]


Solubility (25°C)

In vitro DMSO 20 mg/mL warmed (29.99 mM)
Water Insoluble
Ethanol Insoluble
In vivo Add solvents to the product individually and in order(Data is from Selleck tests instead of citations):
30% PEG400+0.5% Tween80+5% propylene glycol
For best results, use promptly after mixing.
30 mg/mL

* 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 666.7


CAS No. 171599-83-0
Storage powder
in solvent
Synonyms N/A
Smiles CCCC1=NN(C2=C1N=C(NC2=O)C3=C(C=CC(=C3)S(=O)(=O)N4CCN(CC4)C)OCC)C.C(C(=O)O)C(CC(=O)O)(C(=O)O)O

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% DMSO % % Tween 80 % ddH2O

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Mass Concentration Volume Molecular Weight

Clinical Trial Information

NCT Number Recruitment interventions Conditions Sponsor/Collaborators Start Date Phases
NCT03417492 Recruiting Drug: Sildenafil Citrate Traumatic Brain Injury|Mild Traumatic Brain Injury|Post-Concussion Syndrome University of Pennsylvania|Boston University March 1 2018 Phase 1
NCT03177824 Unknown status Drug: Sildenafil Citrate 25Mg Tab|Drug: Placebo Oral Tablet Fetal Growth Restriction Ain Shams University March 30 2017 Phase 3
NCT03262961 Unknown status Drug: Sildenafil 20 MG|Drug: Placebo Oral Tablet Pre-Eclampsia; Mild Assiut University September 15 2016 Phase 2|Phase 3
NCT00165295 Completed Drug: Sildenafil citrate (Viagra) Waldenstrom''s Macroglobulinemia Dana-Farber Cancer Institute|Beth Israel Deaconess Medical Center September 2005 Phase 2

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PDE Signaling Pathway Map

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Cell Lines Assay Type Concentration Incubation Time Formulation Activity Description PMID