Polypeptide and protein drugs With the rapid development of biotechnology, peptide and protein drugs continue to emerge. Currently, 35 important therapeutic drugs are on the market, and the development of biotechnology and biopharmaceutical companies is becoming increasingly global. The focus of biotechnology drug research is the application of DNA recombinant technology to develop peptides, proteins, enzymes, hormones, vaccines, cell growth factors and monoclonal antibodies that can be used clinically. According to Parexl's Pharmaceutical R&D Statistical Source Book, 723 biotech drugs are currently undergoing FDA review (including Phase I to III clinical and FDA evaluation), and 700 drugs are in early research stages (research and preclinical). There are more than 200 drugs that have entered the final stage of approval (Phase III clinical and FDA evaluation). The basic dosage form of biotech drugs is lyophilized. Although the efficacy of conventional preparations has been clinically proven for a long time, due to their short half-life, they require long-term and frequent injections. These are unacceptable problems from the perspective of the patient's psychological and economic burden. To this end, scholars from various countries mainly focus on research and development of convenient and reasonable administration routes and new preparations from two aspects: ① implants and sustained-release injections. ②Non-injection dosage forms, such as respiratory inhalation, rectal administration, nasal cavity, oral and transdermal administration, etc. Injectable preparations of sustained-release biotech drugs are new dosage forms with great application prospects. Some varieties, such as luteinizing hormone-releasing hormone (LHRH) analog microsphere injections that can be sustained-released for 1 to 3 months, are already on the market. This article focuses on such preparations. 1 Main types of sustained-release preparations for polypeptide and protein drugs The research and development of sustained-release preparations for polypeptide and protein drugs are mainly divided into two categories: implants and microsphere injections in terms of development process and dosage forms. 1.1 Implant 1.1.1 Thin rod type implant The shape of the implant is a hollow micro-thin rod, with one end closed and the other end open. The rod is made of non-biodegradable polymers such as polytetrafluoroethylene. A mixture of drug and silica gel (silastic, polydimethylsiloxane) is poured into the cavity. The implant is embedded under the skin of the human body, and the drug is slowly released through the opening of the silicone matrix. The American Physician's Handbook (PDR) lists the implant with the trade name Norplant?, and the drug is levo-18 ethyl norethindrone, which is used for family planning. Each of the preparations has a diameter of 2.4 mm and a length of 34 mm. The doctor surgically implants 6 thin rods on the inside of the patient's upper arm. The drug can be released in the body in zero-level mode for 5 years. After the drug is released, it can be removed through surgery. . 1.1.2 Micro-osmotic pump implant. In the 1970s, Alza Company of the United States developed an implant that looks like a capsule. This preparation is implanted under the skin or other parts. Body fluids can penetrate through the shell, dissolve the interlayer electrolyte, and expand the volume. The interlayer presses against the plastic inner cavity, prompting the drug solution to be released from the opening at a constant rate. There are many reports on in vivo and in vitro animal studies of biological macromolecule drugs, such as insulin, heparin, nerve growth factor, etc. as model drugs. Implants have positive significance in the treatment of chronic patients who require long-term medication, but they have the following shortcomings: ① They must be implanted through surgery. ②The matrix material of the preparation is non-biodegradable polymer, which needs to be removed surgically after drug release. ③The preparation may cause irritation and discomfort in local tissues. Evaluation methods for polypeptide and protein drugs: 1. Liquid chromatography 2. Spectroscopy 3. Electrophoresis 4. Biological activity determination and immunoassay The general prescription composition of polypeptide and protein drugs: the protein drug injections currently used in clinical applications, one type is solvent-based injections , the other type is freeze-dried powder injection. Solvent type is easy to use, but needs to be stored at low temperature (2-8 degrees Celsius).