Tadalafil Powder Details Porduct Name:Tadalafil  English Name: Calais CAS No: 171596-29-5 Molecular formula:: C22H19N3O4 Molecular Weight: 389.41 Purity: 99.5% Appearance: white powder Chemical formula: Tadalafil is cyclic guanosine phosphate (cGMP) specific phosphodiesterase 5 (PDE5) selectivity and reversible inhibitor, when sexual stimulation leads to partial release nitric oxide, tadalafil inhibit PDE5, make the penis sponge body cGMP level, resulting in smooth muscle …