API stands for Active Pharmaceutical Ingredient, which is the main active ingredient in a drug that produces the intended therapeutic effect. Pharmaceutical intermediates, on the other hand, are chemical compounds that are used in the process of manufacturing APIs. They are the building blocks of APIs and are synthesized through a series of chemical reactions.

APIs are used to treat specific diseases or medical conditions, and they must meet certain quality and safety standards. Pharmaceutical intermediates, on the other hand, are not used directly in the treatment of diseases, but they are critical components in the process of synthesizing APIs.

In summary, APIs are intended to provide pharmacological activity or other direct effects in the diagnosis, cure, mitigation, treatment, or prevention of a disease, or to affect the structure or function of the body, while pharmaceutical intermediates are the compounds that are used to manufacture APIs.