CAS Number: 139755-83-2 Formulae chemica: C22H19N3O4 Molecular Weight: 389.4 Content: 99.5% Sildenafil citrate, Viagra Solubility: Leviter solutum in aqua, methanol; very slightly soluble in ethanol, chloroform Appearance: White crystallinum pulveris at: shading, inclusi conservationem. Consuetudinem: Viagra (Sildenafil citrate) is a drug used to treat erectile dysfunction (impotence) in males and pulmonary arterial hypertension (PAH).