As to the original question, just request some time to speak and say you're leaving for an opportunity you can't pass up. Trust me, they'll understand. I think they are fully aware that more than a few CVS pharmacists are open to other opportunities. There may even be some that cheer you on and ask you to keep them in mind for any future openings.
Congrats to you. PV is a steep learning curve, but if you choose to continue within PV there are plenty of opportunities for continuous learning and career growth. Or, it's a foot in the door to industry if you want to explore another function. If you're starting within PV Operations, try to do your best and learn the regulations to the T...and look for ANY opportunities to branch out from Ops and gain experience in project management, quality/compliance, clinical safety, risk management, signal detection, and aggregate reporting. Those are going to be where the more valued PV experience lies and sought after. If you're into programming and the tech side, safety data management is pretty high in demand - more and more companies are looking for this unique combination of skills and there aren't many people who have this experience relative to demand.