Small bottle found in a drug smuggler containing cannabis, mostly (7)
I believe the answer is:
ampoule
'small bottle' is the definition.
(an ampoule is a small container)
'a drug smuggler containing cannabis mostly' is the wordplay.
'drug smuggler' becomes 'mule' (I've seen this in another clue).
'containing' is an insertion indicator.
'cannabis' becomes 'pot' (synonyms).
'mostly' means to remove the last letter.
'pot' with its last letter removed is 'po'.
'mule' enclosing 'po' is 'mpoule'.
'a'+'mpoule'='AMPOULE'
'found in' acts as a link.
(Other definitions for ampoule that I've seen before include "Glass capsule" , "Sealed glass container for injection solution" , "Glass container for hypodermic dose" , "Capsule containing injection dose" , "Vessel holding liquid for injection" .)