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.)
I don't think there is a single word for "compounds mixed by pharmacy then served as a medicine."
The term is compounded drug, compounded medication, or bespoke medication, which you can have made to order at a compounding pharmacy (US) or compounding chemist (UK).
What is compounding?
Drug compounding is often regarded as the process of combining, mixing, or altering ingredients to create a medication tailored to the needs of an individual patient. Compounding includes the combining of two or more drugs. Compounded drugs are not FDA-approved. FDA; "Compounding and the FDA"
There are about 56,000 community-based pharmacies in the U.S. Of them, about 7,500 pharmacies offer compounding services. WebMD; "What is a compounding pharmacy?"
Compounded medications aren’t the same as regular prescription drugs. They’re custom-made formulations that are specific to your needs. They’re usually prescribed when a medication, dose, or dosage form isn’t commercially available.
Not all pharmacies can make compounded medications, especially if it’s an injection or an eye drop. Specialized, accredited compounding pharmacies are your best bet for filling these prescriptions. goodrx.com; "Pharmacist Answers to 6 Common Questions About Compounded Medications"