| abstract |
The present invention in one embodiment relates to a compound of Formula (I); or a pharmaceutically acceptable salt thereof, wherein: each of R 1 and R 2 is independently selected from -CH 3 and -CD 3 ; R 3 is hydrogen or deuterium; each of Z 1 , Z 2 and Z 3 is independently selected from hydrogen and deuterium; each Z 4 is hydrogen or deuterium; each Z 5 is hydrogen or deuterium; and each Z 6 is hydrogen or deuterium. |