Definition 

Biotechnology is the exploitation of biological processes for industrial and other purposes, especially the genetic manipulation of microorganisms for the production of antibiotics, hormones etc.

Biomedical science combines biology and medicine in order to focus on the health of both humans and other organisms.

Scope

Biotechnology has areas of application like healthcare, waste management, agriculture, pollution control, environment etc. One works with DNA, microorganisms, tissues, viruses and complex proteins.

Biomedical science has applications in vaccines, cloning, biofuels, enzymes and drugs. Areas of employment mainly include medical equipment manufacturing, research and health services.

Salaries

Usually quite similar for both ie a fresh graduate may earn 25,000-35,000 per month in India.

Duration

Same for both courses ie 4 years for a BTech degree.

Both courses are quite similar but choose according to your interest. If you want a field that covers a broader scope in natural sciences, choose biotechnology. If you want more focus on medical and engineering principles, opt for biomedical.