No pepper spray is not edible.
Pepper spray is not just pepper but also the pepper spray contains dangerous and poisonous carrier chemicals and if ingested it can make you deathly sick.
Although pepper is edible including cayenne pepper the pepper spray used for self defense should never be eaten because you'll either die or get sick.
Pepper spray is bad enough to get sprayed into your eyes and if someone is attacking someone they deserve to be sprayed with pepper spray.
But you do not want to eat the pepper spray and should keep the pepper spray away from children.
The carrier chemicals that make pepper spray not edible are things including alcohol, cleaning fluid or a paint/grease stripper.