Pharmaceutical APIs (Active Pharmaceutical Ingredients), also known as drug substances, are the biologically active components responsible for the therapeutic effects of a drug. They are the main active compounds that provide the desired pharmacological action in the body. APIs are typically derived from natural sources or synthesized through chemical processes. Here are some key examples:

• Enzymes: Enzyme APIs are biocatalysts that facilitate biochemical reactions in the body. They are used in various therapeutic settings, diagnostics, and industrial processes. Enzyme APIs may include thrombolytic enzymes used to treat blood clots, digestive enzymes for enzyme replacement therapy, and enzyme-based diagnostic reagents for detecting specific biomarkers.
• Hormones: Hormonal APIs are substances that mimic or regulate the functions of natural hormones in the body. They are used for hormonal replacement therapy, contraception, fertility treatment, and various endocrine disorders. Hormonal APIs include insulin, estrogen, progesterone, testosterone, and thyroid hormones.
• Macromolecules and Biologics: These APIs are larger molecules, often derived from living organisms and manufactured using biotechnological processes. They include proteins, peptides, antibodies, and nucleic acids. Macromolecule APIs may have complex structures and are used to treat various diseases, such as insulin for diabetes, monoclonal antibodies for cancer treatment, and interferons for antiviral therapy.
• Small Molecules: This group comprises most traditional drugs in the pharmaceutical market. Small molecule APIs have a low molecular weight and are chemically synthesized. They often target specific receptors or enzymes in the body to exert their therapeutic effect. Examples include aspirin (acetylsalicylic acid), paracetamol (acetaminophen), ibuprofen, and statins used in cholesterol management.
• Vaccines: Vaccines are preparations containing weakened or killed microorganisms, antigens, or recombinant proteins that help stimulate the immune system and provide immunity against infectious diseases. Examples of vaccine APIs include those used for influenza, hepatitis, measles, mumps, rubella, and more. The composition of vaccine APIs can vary widely depending on the specific disease they target.