Tomodachi no Papa - Hakui no Oji-Sama友達のパパ～白衣のオジサマ～

This series is about Rio, a college student who has been in love with her best friend's father, the pharmacist who runs Izumi Pharmacy, ever since she was a kid. As for Izumi-sensei, he's also attracted to Rio but has been holding back because his son is also in love with her!