what can i study after b.pharmacy.
Depends entirely on you, If you want to make money,apply for passport immediately and prepare for IELTS /TOEFL exams so that you can go to countries like US, Canada, Saudi.
There are additional exams to get entry as a registered pharmacist in these countries, you can get everything on net.
If you want to stay in India along with your family, better get in touch with a good doctor and open a medical store near his clinic, as immediately after B.Pharm you can go to manufacturing dept. (which initially offers very less salary, around 5000 Rs per month in Baddi, Himanchal Pradesh. You can easily get carried away by the fact that MRs make huge money, but that job is mostly dominated by non-science graduates and the targets may be very hard to achieve as you have to please all the 3 namely, the Doctor, the Chemist and the Stockist.
Opting for M.Pharm may be another option but you will land in the same situation after 2 yrs. but you can easily get teaching job in any private college.
If you want to apply for Drug inspector after B.Pharm then go for Pharma manufacturing and spend at least 18 months in a firm that manufactures Schedule C drugs, as this is the minimum eligibility to apply for D.I.