5-[5-[(3S,5R)-3,5-dimethylpiperazin-1-yl]sulfonyl-2-ethoxyphenyl]-1-methyl-3-propyl-4H-pyrazolo[4,3-d]pyrimidin-7-one;Methisosildenafil;Aildenafil;MethisosildenafilSolution,100ppm;7H-Pyrazolo[4,3-d]pyrimidin-7-one,5-[5-[[(3R,5S)-3,5-dimethyl-1-piperazinyl]sulfonyl]-2-ethoxyphenyl]-1,6-dihydro-1-methyl-3-propyl-,rel-;5-(5-(((3S,5R)-3,5-dimethylpiperazin-1-yl)sulfonyl)-2-ethoxyphenyl)-1-methyl-3-propyl-1H-pyrazolo[4,3-d]pyrimidin-7(6H)-one;SildenafilImpurity69;Ailidenafil