Drug from nitrogen and oxygen in polar region (8)
I believe the answer is:
narcotic
'drug' is the definition.
(I know that drug can be written as narcotic)
'nitrogen and oxygen in polar region' is the wordplay.
'nitrogen' becomes 'N' (N is the chemical symbol for nitrogen).
'and' says to put letters next to each other.
'oxygen' becomes 'O' (atomic symbol for oxygen).
'in' means one lot of letters goes inside another.
'polar region' becomes 'arctic' (I've seen this in another clue).
'o' placed into 'arctic' is 'arcotic'.
'n'+'arcotic'='NARCOTIC'
'from' is the link.
(Other definitions for narcotic that I've seen before include "Drug that induces drowsiness or stupor" , "this will induce numbness" , "Drug causing numbness and drowsiness" , "Addictive drug affecting mood or behaviour" , "A sleep-inducing drug" .)