Ok, I can usually find things using Google but no luck this time!
This is a film from around mid-90s I think, but could be +/- 10yrs.
Male lead, who I think gets a kind of lethal injection which has so long to take effect. Or it may be a disease which is killing him.
But either way - he has a few hours to achieve his objective.
One of the defining things is that as he gets weaker/the film progresses - the colour fades - so towards the end of the film it is more black and white than colour.