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. http://www.guidechem.com/cas-251/2516-96-3.html 2-Chloro-5-nitrobenzoic acid is used as an intermediate for Bulk Drugs & Dyes and Pigments.