Science Fiction - Abduction Return on Distant Planet

[John]

I think this is adult science fiction, but it just might be very creepy YA science fiction. It starts with a boy and a girl being held hostage by a criminal who, it is strongly implied, rapes them both regularly. The boy has been kidnapped from a sort of walled city where the ruling class lives. The girl has been taken from the lower classes.

The boy is returned at some point (or walks in?) and the guard recognizes from, I think, his retinal scan though it might be DNA or something else.

The upper classes in this society live by providing some sort of life extension drug to their society. They hold a monopoly on natural sources of the drug. The drug can be artificially produce more cheaply, but every time someone tries, they drop the price of the natural drug until the competitor goes out of business.

[Lobstergirl, au gratin]

When did you read it or about when was it published?

[John]

I don't know. Likely sometime in the second half of the 20th century.

[Lobstergirl, au gratin]

John, are you still looking for this or did you find it?

[John]

Haven't found it yet.