If you want to do regulatory affairs, why are you pursuing an MBA? To keep your options open? Or because of genuine interest in business? Regulatory has very little to do with commercial, and a Master's in regulatory affairs (some schools do offer it) would help you more. Not easy to get into Reg Affairs right out of school with a PharmD. Unless you do a fellowship, you may be out of luck. You cost too much to be hired for the very lowest worker bee level, and anything else requires at least one year of direct experience. Even transferring internally into regulatory can be quite a feat, they tend to be suspicious of anyone coming down from the commercial side, in my experience (and an MBA smells of sulfur commercial). Coming to them from the Med Affairs side may be easier, especially if you work on promotional materials review a lot and can get really good working relationship with your regulatory partners.