Sildenafil citrate

Sildenafil is a potent inhibitor of phosphodiesterase 5 (PDE5) with IC₅₀ values of 3.6 and 3 nM for PDE5 activity in isolated rabbit platelets and human corpus cavernosum, respectively. It is selective for PDE5 over PDE1 and PDE3 (IC₅₀s = 0.26 and 65 μM, respectively). Sildenafil reverses glucose-induced decreases in angiopoietin 1 (ANG1) expression and reduction of capillary-like tube formation by mouse dermal endothelial cells in vitro and increases the number of functional blood vessels and regional blood flow in the sciatic nerve in a db/db mouse model of diabetic peripheral neuropathy. It increases the ratio of maximum intracavernosal pressure to mean arterial blood pressure (ICP/MAP), a measure of erectile function, in castrated rats when administered at a dose of 20 mg/kg per day. Sildenafil (0.5 mg/kg) also reduces cardiac arrest and resuscitation-induced increases in angiotensin II , angiotensin converting enzyme (ACE), ACE2, and various angiotensin receptors and increases survival in a porcine model of ischemia/reperfusion injury. Formulations containing sildenafil have been used in the treatment of erectile dysfunction, pulmonary arterial hypertension, and high-altitude pulmonary edema associated with altitude sickness.

Sildenafil citrate is a white to off-white crystalline powder soluble in DMF, acetic acid and slightly soluble in methanol. Solubility of sildenafil citrate is pH dependent and it decreases with increase of pH. pH ranges between 3.7 and 3.8 and the pKa from 8.2 to 9.6.

Sildenafil citrate is an orally active selective type 5 cgmp phosphodiesterase inhibitor that is used in the treatment of erectile dysfunction and primary pulmonary hypertension.

ChEBI: Sildenafil citrate is the citrate salt of sildenafil. It has a role as a vasodilator agent and an EC 3.1.4.35 (3',5'-cyclic-GMP phosphodiesterase) inhibitor. It contains a sildenafil.

Sildenafil Citrate is the citrate salt form of sildenafil, an orally bioavailable pyrazolopyrimidinone derivative structurally related to zaprinast, with vasodilating and potential anti-inflammatory activities. Upon oral administration, sildenafil selectively targets and inhibits cyclic guanosine monophosphate (cGMP)-specific phosphodiesterase type 5 (PDE5), thereby inhibiting the PDE5-mediated degradation of cGMP found in smooth muscle and increasing cGMP availability. This results in prolonged smooth muscle relaxation in the corpus cavernosum of the penis, thereby causing vasodilation, blood engorgement and a prolonged penile erection.  In the smooth muscle of the pulmonary vasculature, the increase in cGMP results in smooth muscle relaxation, vasodilation of the pulmonary vascular bed, relieving pulmonary hypertension and increasing blood flow in the lungs. In addition, sildenafil may reduce airway inflammation and mucus production.

Orally active, potent inhibitor of phosphodiesterase 5 (PDE5) (IC 50 = 4 nM). Enhances nitric oxide-dependent relaxation of human corpus cavernosum in vitro .

Analysis of Middle Eastern data (mean ± SD) revealed Cmax = 398.9 ± 107.7 ng/ml; Tmax = 1.84 ± 0.22 h; t1/2 = 2.66 ± 0.97 h; AUC0–24 = 1475 ± 515.3 ng.h/ml; AUC0-∞ = 1556 ± 567.58 ng.h/ml.

The more common side effects of sildenafil citrate include: headache, skin flushing, indigestion, abnormal vision, nasal congestion, back pain, nausea, dizziness, rash, etc.

A poison by ingestion. Human systemic effects. When heated to decomposition it emits toxic vapors of NOx and SOx.