Innerspace

Innerspace is a 1987 science fiction comedy film. It's a take-off of Fantastic Voyage in that people are miniaturized and injected into someone. It stars Dennis Quaid, Meg Ryan, Martin Short, Robert Picardo (who has a Star Trek connection), William Schallert and Henry Gibson (yes, that Henry Gibson).

Youtube has it online in 12 parts. Part 1:

part 2, part 3, part 4, part 5, part 6, part 7, part 8, part 9, part 10, part 11, part 12

Moria says it's "just a chaotic comedy that never came to life". Roger Ebert calls it "an absurd, unwieldy, overplotted movie that nevertheless is entertaining". The New York Times has a review.