Interest in Gladstone for example (3)
I believe the answer is:
bag
I believe this clue is a double definition.
'interest in' is the first definition.
(I've seen this before)
'gladstone for example' is the second definition.
(gladstone is a kind of bag)
(Other definitions for bag that I've seen before include "Flexible container for carrying things" , "Flexible container for shopping" , "Container for holding or carrying" , "Valise" , "Sack" .)