In my experience there are two things more potent than catnip - actinidia kolomikta (my avatar - Sam - goes mad for it in spring when it resurfaces) and weigela (ditto)
If your cat doesn't react to catnip. Try them on Cosmic, or better still Canadian bud much stronger than the UK types which include a lot of woody material. Best ready made catnip mice are the Zebedee ones