Polypeptides can be said to be widely found in biological systems, signaling molecules, transmission molecules, and digestive molecules. As a signal molecule, the polypeptide controls the biological functions of organisms such as cell division, mating, chemotaxis, pain, growth and immunity, and peptide synthesis has become the most potent tool for biochemistry, pharmacology, immunology and biophysical research As a transport molecule, the polypeptide can promote the passage of ions through the cell membrane pathway; as a digestive molecule, the polypeptide plays an important role in the nutrient uptake of cells and intact organisms. In addition, the polypeptide can also be used as a protective agent, such as antibiotics with excellent antibacterial and antiviral properties. Now, peptides are important business entities that have been used in different therapeutic areas such as diabetes, allergies, anti-infectives, obesity, diagnostics, cancer, arthritis and cardiovascular disease.
Because peptide drugs are mainly derived from endogenous peptides or other natural peptides, usually, its structure is clear, the mechanism of action is clear, many properties are often between the small molecule chemical drugs and macromolecule protein / antibody between, such as small Molecular chemicals, half-life is generally very short, unstable, easy to be rapidly degraded in the body, the preparation of unstable to be cryopreserved, the cost of small molecular high drug (especially long chain polypeptide), and so on; and macromolecular protein phase Better stability, less dosage, higher unit activity, lower cost, and chemical synthesis of peptides mature technology, easy to separate from impurities or by-products, high purity.
Some of the shortcomings of the above-mentioned problems, such as stability problems, some of the peptides can be modified by modification or with other materials to form a stable complex; cost problems, with advances in technology, equipment updates and process improvement, the cost has been better control. Peptide drugs the biggest problem, in fact, can not be oral, mainly because it is easy to be degraded and difficult to pass through the intestinal mucosa, but there are also a variety of other alternative routes such as subcutaneous injection, nasal jet and so on.