Drug company badly need to contain source of inflammation (7)
I believe the answer is:
codeine
'drug' is the definition.
(codeine is a kind of drug)
'company badly need to contain source of inflammation' is the wordplay.
'company' becomes 'co' (abbreviation).
'badly' indicates an anagram.
'to contain' is an insertion indicator.
'source of' indicates taking the first letters.
The first letter of 'inflammation' is 'i'.
'need' with letters rearranged gives 'dene'.
'dene' enclosing 'i' is 'deine'.
'co'+'deine'='CODEINE'
(Other definitions for codeine that I've seen before include "Derivative of opium used as an analgesic" , "Mild narcotic used as a pain-killer" , "Common opium-based tablet used to relieve pain" , "Common painkiller" , "Analgesic drug" .)