I had the same thing with pharma as well. I got the usual questions:
1. Experiences
2. Why should they give you the job?
3. Knowledge of the subject area, etc
4. Random questions out of left field. Usually utterly irrelevant.
Just be honest, that's the most important bit and feel free to offer your opinion. After all, they want someone who can think, not an automaton. My advice: don't worry about it, just go in, relax and take time to think about your answers!