Yakuchu! ~Tadaima Biyaku Kaihatsuchuu~

Main character is a 4th year student at the medical college. But he is also a genius who secretly studies new drugs in the laboratory. It's high time for him to do job hunting, but he misses the best season for it. His acquaintance invites him to a hospital that has majority of staff left due to director getting ill. It's only a matter of time until this facility closes down, but it's a perfect opportunity to test different drugs and maybe even a pharmaceutical company as a result.

[From vndbreview]