A bulk drug --- also called active pharmaceutical ingredient
(API), are synthesized through chemical or biological process
(chemical change), they can not be directly taken. The medicines in
the markets in the "form" of tablets, capsules, syrups, drops,
intravenous fluids etc., are therefore "formulations." They can be
taken directly. Although most formulations contain only one bulk
drug, there are a large number of formulations containing more than
one bulk drug.