This was a Scifi I saw probably around '82-84 on tape, most likely in the era before home video in the UK was rated.
Somewhat similar to movies like Starcrash and Spacehunter: Adventures in the Forbidden Zone, but darker and more 'adult'.

Main plot I don't recall but it was a typical space opera good vs evil, the good guy being a swashbuckling Han Solo type, up against an evil empress whos 'hook' was that she would place slave girls into a transparent sarcophagus/iron maiden like device which would drain them of all their fluids, which she would somehow use in order to say young.

The movie ended with the 'Han Solo' rescuing his underappreciative female sidekick from that very fate before (probably) blowing up the Empresses flagship

I recall that when the victim was being exsanguinated you got the pre-cert gratuitous booby shot, but when it was the leading ladies turn she was fully clothed, so must have been an actress with at least some reputation or standing if she wasn't willing to bare all.

Hopefully someone has a clue as to what it is.

Cheers