People take drugs to cure, diagnose, treat or prevent disease. Most drugs contain several ingredients. The most important is the API, which stands for active pharmaceutical ingredient. This is the actual substance in the drug that must work in your body.
For example, the API in aspirin is "acetylsalicylic acid". This API will try to fight the pain of your fever or headache. Some drugs carry the name of an API. For example, the API for paracetamol is "paracetamol". To make a pill, you need more ingredients than just the API. this is where the excipients come into play. These ingredients are used to give the pill, for example, volume, sweetness or color.
From natural medicines. Natural drugs are an important part of medicine. An example is artemisinin, the active antimalarial ingredient isolated from the Chinese herb Artemisia annua.
Existing drugs are used as first arrivals.
1) Discovery of drug active ingredients from drug side effects. For example, the phenothiazine antipsychotic chlorpromazine and its analogs were developed from the sedative side effects of the structurally similar antihistamine promethazine.
2) Obtained through drug metabolism studies. For example, the metabolites of the antidepressants promethazine and amitriptyline, norethindrone and norethindrone, have stronger antidepressant effects than the original drugs; oxazepam is the active metabolite of diazepam.
3) Use existing breakthrough drugs as a precursor. For example, lansoprazole and other razoles were studied with ah, omeprazole as a lead, which is more active than omeprazole activity.
Obtained by screening with pharmacological models. By the method of combinatorial chemistry, a large number of chemical libraries with different structures are constructed, and the separation of mixtures is not carried out, and the active compounds are separated after their components are found to be pharmacologically active by high-throughput screening, and the structures of the active compounds are determined.