1. Metabolic Enzyme/Protease
  2. Phosphodiesterase (PDE)

Sildenafil citrate (Synonyms: UK-92480 citrate)

Cat. No.: HY-15025A Purity: 99.84%
Handling Instructions

Sildenafil citrate is a potent phosphodiesterase type 5 (PDE5) inhibitor with IC50 of 5.22 nM.

For research use only. We do not sell to patients.
Sildenafil citrate Chemical Structure

Sildenafil citrate Chemical Structure

CAS No. : 171599-83-0

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Free Sample (0.5-1 mg)   Apply now  
10 mM * 1 mL in DMSO USD 66 In-stock
10 mg USD 60 In-stock
50 mg USD 114 In-stock
100 mg USD 156 In-stock
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Other Forms of Sildenafil citrate:

  • Biological Activity

  • Protocol

  • Technical Information

  • Purity & Documentation

  • References


Sildenafil citrate is a potent phosphodiesterase type 5 (PDE5) inhibitor with IC50 of 5.22 nM.

IC50 & Target

IC50: 5.22 nM (PDE 5)[1]

In Vitro

Pretreatment with 1 μM Sildenafil citrate potentiates the phosphorylation of ERK1/ERK2, an increase in the percentage of cells in S phase and cell proliferation, compared with serotonin stimulation alone (P<0.05). Pretreatment with 1 μM Sildenafil citrate followed by serotonin stimulation leads to dramatic increase in OD value to 0.33, significantly different compared with serotonin stimulation alone (P<0.05). 1 μM Sildenafil obviously enhances the upregulation of ERK1/ERK2 phosphorylation induced by serotonin[2].

In Vivo

In the dog model of erection, Sildenafil citrate significantly increases ICP and ICP/BP but shows no significant effect on BP compared with vehicle[1]. Sildenafil treatment significantly decreases the number of TL+-cells at 10 but not 0.5 mg/kg. At this time point, cells positive for the M1-like marker COX-2+ are found in the ischemic core in PBS-treated animals, whereas they are mostly observed in the penumbra in 10 mg/kg (but not 0.5 mg/kg) Sildenafil-treated animals. In contrast, 8 days after pMCAo the number of microglia/macrophages stained by Iba-1 are significantly reduced by Sildenafil treatment (0.5 and/or 10 mg/kg dose)[3]. Sildenafil citrate has been reported to decrease flap necrosis in preclinical animal models by increasing the secretion of growth factors (FGF and VEGF), and histologically is shown to be effective in rat cavernous nerve architecture[4].

Clinical Trial
Preparing Stock Solutions
Concentration Volume Mass 1 mg 5 mg 10 mg
1 mM 1.4999 mL 7.4996 mL 14.9992 mL
5 mM 0.3000 mL 1.4999 mL 2.9998 mL
10 mM 0.1500 mL 0.7500 mL 1.4999 mL
Please refer to the solubility information to select the appropriate solvent.
Cell Assay

Sildenafil is prepared in DMSO and stored, and then diluted with appropriate medium before use[2].

Cells at approximately 90% confluence are harvested with 0.1% trypsin/0.01% ethylene diamine tetraacetic acid (EDTA) solution and seeded into a 96-well plate at a density of 2×104 cells/well and grown in RPMI-1640 containing 10% FBS for three days, followed by serum starvation for three days. Cells are then incubated for different time with various concentration of serotonin or 1 μM Sildenafil followed by serotonin with or without U0126, as indicated. Control cells are treated in the same way except sterile PBS replaced the drug. After treatment, medium is changed to fresh medium, and cells are incubated with 5 g/L of MTT for four hours. MTT is then dissolved with 150 μL of 10% DMSO for 20 minutes. The optical densities (OD) in the 96-well plates are determined using a microplate reader at 570 nm[2]. MCE has not independently confirmed the accuracy of these methods. They are for reference only.

Animal Administration

Sildenafil citrate is prepared in PBS.

Ischemia is induced in C57Bl/6 mice on postnatal (P) day 9 by permanent middle cerebral artery occlusion (pMCAo), and followed by either PBS or Sildenafil intraperitoneal (i.p.) injections. In the first set of experiments, animals are randomly divided into five groups and treated with either PBS or a single dose of Sildenafil citrate (0.5, 2.5, 10, and 15 mg/kg), given intraperitoneally (i.p.) 5 min after pMCAo. In the second set of experiments, animals are randomly divided into three groups and treated with either PBS or a single dose of Sildenafil citrate (0.5 and 10 mg/kg, i.p.) 5 min after pMCAo.
Thirty male Sprague-Dawley rats weighing between 210 and 240 g are used. Rats from all groups are anesthetized with xylazine + ketamine and then a crush injury is created by using a one-minute long vascular clamp to the right sciatic nerve. One day before the procedure, rats from Group 1 are started on a 28-day treatment consisting of a daily dose of 20 mg/kg body weight Sildenafil given orally via nasogastric tube, while the rats from Group 2 are started on an every-other-day dose of 10 mg/kg body weight Sildenafil citrate. Rats from Group 3 did not receive any drugs. Subjects in all 3 groups are fed ad libitum with normal rat chow and tap water. Forty-two days after the nerve damage is created, the rats underwent a static sciatic index (SSI) test, sedation and motor coordination tests, and accelerated rotarod tests. Rats are sacrificed under anesthesia and their sciatic nerves are removed surgically. Histopathologic analyses of the nerves and bone densitometry evaluation of the extremities are then performed. MCE has not independently confirmed the accuracy of these methods. They are for reference only.

Molecular Weight






Powder -20°C 3 years
  4°C 2 years
In solvent -80°C 6 months
  -20°C 1 month

Room temperature in continental US; may vary elsewhere

Solvent & Solubility

DMSO: ≥ 29 mg/mL

* "<1 mg/mL" means slightly soluble or insoluble. "≥" means soluble, but saturation unknown.

Purity: 99.84%

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