As nouns the difference between relaxant and immobilon
is that relaxant is something which promotes relaxation while immobilon is a mixture of etorphine and a tranquilizer, used in veterinary medicine as a muscle relaxant.
relaxant
English
Noun
(
en noun)
Something which promotes relaxation.
References
* OED2
----
immobilon
English
Noun
(-)
A mixture of etorphine and a tranquilizer, used in veterinary medicine as a muscle relaxant