Powder in hospital container (4)
I believe the answer is:
talc
'powder' is the definition.
(I know that talc is a type of powder)
'in hospital container' is the wordplay.
'in' indicates the answer is hidden within the clue.
'TALC' is hidden within 'hospital container'.
(Other definitions for talc that I've seen before include "soother" , "Magnesium silicate powder" , "Softest mineral on Mohs hardness scale" , "After-bath powder" , "Cosmetic powder" .)