Anyone could help me to provide a term for compounds mixed by pharmacy then served as a medicine? Could I still just use materia medica nowadays? Thanks.
Looking at my local dictionary's definition for material medica, it appears this is an acceptable usage:
material medica — 2. medicinal drugs: the substances used to make medicinal drugs
Aside from that, the more generic term is "drug":
A drug is a substance which may have medicinal, intoxicating, performance enhancing or other effects when taken or put into a human body or the body of another animal and is not considered a food or exclusively a food.
Drugs are then combined into medicines using pharamcology. An example of usage that is similar to your request (pulled from various Wikipedia articles):
New chemical entities are compounds which emerge from the process of drug discovery. [...] A new chemical entity is, according to the U.S. Food and Drug Administration, a drug that contains no active moiety that has been approved by the FDA.
This roughly implies that drugs are medicial compounds and it would appear appropriate to use the term as such. (You could also just use the word compounds as this was very common among the articles I browsed on the subject.)