How is sleep medication absorbed?

Can be different way and time.
Depends how they are covered.
If it is regular tablet,then will absorb much faster,then if it is in capsule.
Usually medications in capsules are done to be solved further then in stomach -in duodenum or sometimes in intestinal system.
Period of absorption can vary.
From 1 min up to 1 hr.
Injections work much faster.