Drug featured in musical item the writer’s set around university (5)
I believe the answer is:
opium
'drug' is the definition.
(opium is a kind of drug)
'musical item the writer's set around university' is the wordplay.
'musical item' becomes 'op' (I can't explain this - if you can you should give a lot more credence to this answer).
'the writer's' becomes 'I'm' (both could mean 'the crossword setter is').
'set around' is an insertion indicator.
'university' becomes 'U' (abbreviation for university).
'im' going around 'u' is 'ium'.
'op'+'ium'='OPIUM'
'featured in' is the link.
Can you help me to learn more?
(Other definitions for opium that I've seen before include "analgesic" , "justification for war once?" , "Poppy drug" , "De Quincey confessed to eating it" , "Dried juice of white poppy" .)