The short version of 二肽基肽酶-4 fits in a sentence. The long version — which is the one that helps — is below.
Reviewed 2025-11-24. Anything still debated is marked as such rather than presented as settled.
Two principal therapeutic variants exist under separate regulatory filings, one indicated for glycemic control in type 2 diabetes and one for chronic weight management. Both use the same active molecule; differences lie in formulation strength, titration schedule, and labeling. Regulatory agencies in the United States and European Union approved injectable forms in 2017 and 2018 respectively. An oral tablet formulation received approval later, using a carrier molecule to enhance absorption across the gastric epithelium. Labeling differs by jurisdiction and by indication.
The distinction between established facts and open questions matters here. That the peptide binds the GLP-1 receptor and stimulates insulin release in a glucose-dependent manner is well documented. How individual variability in receptor density, gastric emptying rate, and gut microbiome composition shapes response remains an active research area. Long-term outcomes beyond five years of continuous use are not yet fully characterized in published trials, and several extension studies are ongoing.
Reverse-phase high-performance liquid chromatography is the standard method for purity assessment, separating the peptide from truncated or oxidized variants. Mass spectrometry confirms molecular mass and detects modifications, while ultraviolet absorbance near 280 nanometers supports concentration measurement through tryptophan and tyrosine residues. Circular dichroism can indicate secondary structure, though the peptide is largely helical in solution, and ion-exchange chromatography resolves charge variants. Purity values above 95 percent are typical for research-grade material. Stability studies track degradation over time under defined conditions.
Lyophilized semaglutide is typically stored at temperatures between minus 20 and minus 80 degrees Celsius for long-term preservation. Short-term storage at 2 to 8 degrees Celsius is common for working aliquots. Repeated freeze-thaw cycles can degrade the peptide and are usually avoided. The molecule is hygroscopic in its solid form, so containers should remain sealed with desiccant. Solutions are less stable than powders and are generally prepared fresh. Light exposure is limited because aromatic residues can undergo photo-oxidation.
| Property | Value | Notes |
|---|---|---|
| Molecular formula (free base) | C187H291N45O59 | Approximate; salt and hydrate forms differ |
| Molecular weight | ~4113.6 Da | Varies with counterion and hydration |
| Appearance | White to off-white powder | Lyophilized research material |
| Solubility class | Freely soluble in water | As formulated; native peptide less stable near neutral pH |
| Typical storage | 2 to 8 degrees Celsius | Protect from light; avoid repeated freeze-thaw |
The semaglutide sequence is a 31-residue analogue of human GLP-1, altered at three positions relative to the parent hormone. Aminoisobutyric acid replaces alanine at position 8, arginine replaces lysine at position 34, and a lipophilic diacid is attached to lysine 26 through a short linker. These features are reported consistently in the structural literature. The position 8 substitution blocks recognition by dipeptidyl peptidase-4, while the attached chain drives strong, reversible association with a carrier protein in blood.
Receptor activation raises intracellular cyclic AMP through Gs coupling, which promotes glucose-dependent insulin release and suppresses glucagon secretion when blood glucose is elevated. Effects outside the pancreas include slower gastric emptying and altered appetite signalling in the hypothalamus and hindbrain. The relative contribution of each tissue to overall metabolic outcomes remains an area of active investigation. Central mechanisms in particular are inferred mainly from animal models and indirect human measures rather than direct observation.
Serum protein binding dominates the pharmacokinetic profile. The attached chain associates strongly with albumin, shielding the peptide from enzymatic attack and slowing filtration by the kidney. This interaction extends the circulation half-life to roughly one week in humans, which supports weekly administration intervals. An oral version pairs the peptide with an absorption enhancer that transiently alters gastric epithelium, permitting limited uptake; bioavailability by that route is substantially lower than by injection.
The company that developed the compound filed it as a long-acting analogue, and it gained first approval in 2017 for type 2 diabetes. Later authorisations from several regulators extended the indication to chronic weight management, and the World Health Organization added the glucagon-like peptide-1 receptor agonist drug class to its model list of essential medicines in 2023. Production uses solid-phase peptide synthesis followed by side-chain conjugation and chromatographic purification. Supply constraints and cost differences across regions are well documented. Literature on long-term outcomes continues to grow, with many trials reporting surrogate endpoints rather than hard clinical endpoints.
Semaglutide is a synthetic peptide of thirty-one amino acids that shares roughly ninety-four percent sequence identity with human glucagon-like peptide-1. Two substitutions resist enzymatic cleavage by dipeptidyl peptidase-4, and a fatty diacid side chain attached through a linker promotes binding to serum albumin. That albumin binding slows renal clearance and extends the circulating half-life from minutes to approximately one week. The structural changes are well established in the published literature. Whether the same modifications affect receptor signalling bias in ways that matter clinically remains an open question.
Pharmacological activity arises from agonism at the glucagon-like peptide-1 receptor, a G protein-coupled receptor expressed in the pancreas, the gastrointestinal tract, and the brainstem. Receptor activation raises intracellular cyclic adenosine monophosphate and enhances insulin release in a glucose-dependent manner, an effect that diminishes when blood glucose concentration is low. Other effects include slowed gastric emptying and hypothalamic satiety signalling. These pathways are described well. Receptor desensitisation rates across tissues, relative to the endogenous hormone, are still under investigation, and reported findings differ between laboratories.
Storage at minus 20 degrees Celsius or lower in a desiccated container preserves the peptide for extended periods, while working solutions are commonly held at two to eight degrees Celsius for short intervals. Light exposure and repeated freeze-thaw cycles accelerate degradation, so dividing material into single-use aliquots is generally recommended. Adsorption to glass and plastic surfaces can lower the measured concentration of dilute solutions, particularly below one milligram per millilitre. The degradation routes most often reported for GLP-1 analogues are deamidation, methionine oxidation, and backbone hydrolysis. Relative rates under specific conditions are frequently described only for individual formulations.
Reverse-phase high-performance liquid chromatography with ultraviolet detection near 214 or 280 nanometres is widely used to assess purity and to resolve related impurities. Liquid chromatography coupled to mass spectrometry confirms identity through the protonated molecular ion and fragment ions formed in tandem experiments. Capillary electrophoresis and peptide mapping after enzymatic digestion supply complementary information on charge variants and modification sites. Circular dichroism and nuclear magnetic resonance can report on secondary structure in solution. Absolute quantification usually depends on an external standard, and reported purity depends on the detection wavelength and integration parameters chosen.
Lyophilised material appears as a white to off-white cake or powder that is hygroscopic, and containers are usually equilibrated to room temperature before opening to limit condensation. Dissolution is performed in water, phosphate-buffered saline, or a mildly alkaline buffer, since solubility rises above neutral pH. Gentle inversion or low-speed mixing is preferred, because vigorous vortexing can promote surface denaturation and aggregation. Complete dissolution may require several minutes, and brief sonication is sometimes applied. Passing the solution through a 0.22 micrometre membrane removes particulates but does not by itself sterilise the liquid.
序列层面的改动同时解决了两个问题，即酶解稳定性与肾脏清除速度。天然 GLP-1 在循环中的半衰期仅约两分钟，主要被二肽基肽酶-4 迅速灭活。酰化侧链与白蛋白的可逆结合形成循环储库，使分子缓慢释放并持续激活受体。这种设计思路后来被广泛用于同类长效肽的开发，属于该类药物化学改造的典型范式。
Semaglutide 是一种经结构修饰的胰高血糖素样肽-1 类似物，其主链与内源性 GLP-1(7-36) 约有百分之九十四的序列一致性。第 8 位丙氨酸被 α-氨基异丁酸取代，使二肽基肽酶-4 无法识别原有切割位点。第 34 位赖氨酸换为精氨酸，进一步降低酶解速率。第 26 位赖氨酸经间隔基连接一条含十八个碳的二酸脂肪链，该侧链赋予分子与血浆白蛋白结合的能力。
The mammalian cell production process, as used for most biopharmaceuticals, is divided into the four main steps: (1) Cultivation, or the reproduction of the cells; (2) Fermentation, or the actual production of the protein, typically in 10,000 Liter bioreactors; (3) Purification, or the separation of the cells from the culture medium and purification, mostly by chromatography; (4) Formulation, or the conversion of the sensitive proteins to a stable form. All steps are fully automated. The low productivity of the animal culture makes the technology expensive and vulnerable to contamination, as a small amount of bacteria would soon outgrow a larger population of animal cells. Its main disadvantages are low volume productivity and the animal provenance. It is conceivable that other technologies, particularly plant cell production, will gain importance in future. Given the fundamental differences between the two process technologies, plants for mammalian cell culture technologies have to be built ex novo. The pros and cons of an involvement of a fine chemical company in cell culture technology are listed below: Pros:
Myelofibrosis can be a late complication of other myeloproliferative disorders, such as polycythemia vera, and less commonly, essential thrombocythemia. In these cases, myelofibrosis occurs as a result of somatic evolution of the abnormal hematopoietic stem cell clone that caused the original disorder. In some cases, the development of myelofibrosis following these disorders may be accelerated by the oral chemotherapy drug hydroxyurea.
== History == Buspirone was first synthesized by a team at Mead Johnson in 1968 but was not patented until 1980. It was initially developed as an antipsychotic acting on the D2 receptor but was found to be ineffective in the treatment of psychosis; it was then used as an anxiolytic. In 1986, Bristol-Myers Squibb gained FDA approval for buspirone in the treatment of GAD. The patent expired in 2001, and buspirone is available as a generic drug.
=== Sludges and fecal materials from sanitation processes === In the area of sanitation, drying of sewage sludge from sewage treatment plants, fecal sludge or feces collected in urine-diverting dry toilets (UDDT) is a common method to achieve pathogen kill, as pathogens can only tolerate a certain dryness level. In addition, drying is required as a process step if the excreta based materials are meant to be incinerated.
==== Reactions of tyrosines ==== Tyrosine residues are relatively unreactive; therefore they have not been a popular targets for bioconjugation. Recent development has shown that the tyrosine can be modified through electrophilic aromatic substitutions (EAS) reactions, and it is selective for the aromatic carbon adjacent to the phenolic hydroxyl group. This becomes particularly useful in the case that cysteine residues cannot be targeted. Specifically, diazonium effectively couples with tyrosine residues (diazonium salt shown as reagent in the first reaction in Figure 3 below), and an electron withdrawing substituent in the 4-position of diazonium salt can effectively increase the efficiency of the reaction. Cyclic diazodicarboxyamide derivative like 4-Phenyl-1,2,4-triazole-3,5-dione (PTAD) were reported for selective bioconjugation on tyrosine residues (the second reaction in Figure 3 below). A three-component Mannich-type reaction with aldehydes and anilines (the last reaction in Figure 3) was also described to be relatively tyrosine-selective under mild optimised reaction conditions.
Sources: en.wikipedia.org
=== Volatiles === Cultivars of G. globosa vary in the identity of floral volatiles but the volatile compounds of nonanal, decanal, geranyl acetone, and 4,8,12-tetradecatrienal, 5,9,13-trimethyl, were commonly detected by chromatography-mass spectrometry analysis. The cultivar ‘Fireworks’ has a high abundance of volatile esters such as geranyl propionate, geranyl isovalerate, benzyl isovalerate, and benzyl tiglate. The floral volatile emission of this cultivar of G. globosa was found to exhibit a diurnal pattern independent of light. Emission of floral volatiles can be regulated by phytohormone and defense signaling molecules. Experimentally, the ethylene inhibitor silver thiosulphate increased volatile emission of molecules derived from the terpenoid pathway. Defense signaling molecules can have temporal effects on floral volatile emission such as increased emission after four hours and reduced emission of volatiles after 24 hours in time studies analyzed with chromatography-mass spectrometry.
Crocodiles are protected in many parts of the world, and are farmed commercially. Their hides are tanned and used to make leather goods such as shoes and handbags; crocodile meat is also considered a delicacy. The most commonly farmed species are the saltwater and Nile crocodiles. Farming has resulted in an increase in the saltwater crocodile population in Australia, as eggs are usually harvested from the wild, so landowners have an incentive to conserve their habitat. Crocodile leather is made into wallets, briefcases, purses, handbags, belts, hats, and shoes. Crocodile oil has been used for various purposes. Snakes are also farmed, primarily in East and Southeast Asia, and their production has become more intensive in the last decade. Snake farming has been troubling for conservation in the past as it can lead to overexploitation of wild snakes and their natural prey to supply the farms. However, farming snakes can limit the hunting of wild snakes, while reducing the slaughter of higher-order vertebrates like cows. The energy efficiency of snakes is higher than expected for carnivores, due to their ectothermy and low metabolism. Waste protein from the poultry and pig industries is used as feed in snake farms. Snake farms produce meat, snake skin, and antivenom. Turtle farming is another known but controversial practice. Turtles have been farmed for a variety of reasons, ranging from food to traditional medicine, the pet trade, and scientific conservation. Demand for turtle meat and medicinal products is one of the main threats to turtle conservation in Asia.
21CFR50.3: Code of Federal Regulations, Title 21--Food and Drugs, Chapter I--Food and Drug Administration, Department of Health and Human Services, Part 50--Protection of Human Subjects, Subpart A--General Provisions, Sec. 50.3 Definitions 21CFR312.3: Code of Federal Regulations, Title 21--Food and Drugs, Chapter I--Food and Drug Administration, Department of Health and Human Services, Part 312--Investigational New Drug Application, Subpart A--General Provisions, Sec. 312.3 Definitions and Interpretations, archived from the original on June 26, 2003 ICH E6: Guidance for Industry - E6 Good Clinical Practice: Consolidated Guidance (PDF), U.S. Department of Health and Human Services, Food and Drug Administration, April 1996, archived from the original (PDF) on July 9, 2009 ICH E9: Guidance for Industry - E9 Statistical Principles for Clinical Trials (PDF), U.S. Department of Health and Human Services, Food and Drug Administration, September 1998, archived from the original (PDF) on July 10, 2009 NCI: Dictionary of Cancer Terms, National Cancer Institute, archived from the original on 2008-10-25, retrieved 2008-10-05 NLM: Glossary of Clinical Trials Terms, U.S. National Library of Medicine, archived from the original on 2011-09-02, retrieved 2008-10-05
=== Therapeutic evaluation === Several investigations correlate the Bristol stool scale in response to medications or therapies, in fact, in one study was also used to titrate the dose more finely than one drug (colestyramine) in subjects with diarrhoea and faecal incontinence. In a randomised controlled study, the scale was used to study the response to two laxatives: Macrogol (polyethylene glycol) and psyllium (Plantago psyllium and other species of the same genus) of 126 male and female patients for a period of 2 weeks of treatment; failing to show the most rapid response and increased efficiency of the former over the latter. The primary outcomes were the number of weekly bowel movements, stool consistency according to the Bristol stool scale, time to defecation, overall effectiveness, difficulty in defecating, and stool consistency. From 2010, several studies have used the scale as a diagnostic tool validated for recognition and evaluation of response to various treatments, such as probiotics, moxicombustion, laxatives in the elderly, preparing Ayurvedic poly-phytotherapy filed TLPL/AY, psyllium, mesalazine, methylnaltrexone, and oxycodone/naloxone, or to assess the response to physical activity in athletes.
== History == Carbamazepine was discovered by chemist Walter Schindler at J.R. Geigy AG (now part of Novartis) in Basel, Switzerland, in 1953. It was first marketed as a drug to treat epilepsy in Switzerland in 1963 under the brand name Tegretol; its use for trigeminal neuralgia (formerly known as tic douloureux) was introduced at the same time. It has been used as an anticonvulsant and antiepileptic in the United Kingdom since 1965, and has been approved in the United States since 1968. Carbamazepine was studied for bipolar disorder throughout the 1970s.
Sources: en.wikipedia.org
biofilm A community of symbiotic microorganisms, especially bacteria, where cells produce and embed themselves within a slimy, sticky extracellular matrix composed of various high-molecular weight biopolymers, adhering to each other and sometimes also to a substratum, which may be a biotic or abiotic surface. Many bacteria can exist either as independent single cells or switch to a physiologically distinct biofilm phenotype; those that create biofilms often do so in order to shelter themselves from harmful environments. Cells residing within biofilms can easily share nutrients and communicate, and subpopulations of cells may differentiate to perform specialized functions supporting the whole biofilm.
In the late 1970s and in the 1980s, the Socialist International had extensive contacts and held discussion with the two powers of the Cold War, the United States and the Soviet Union, regarding the relations between the East and West, along with arms control. Since then, the Socialist International has admitted as member parties the Nicaraguan Sandinista National Liberation Front and the left-wing Puerto Rican Independence Party as well as former communist parties such as the Italian Democratic Party of the Left and the Front for the Liberation of Mozambique. The Socialist International aided social democratic parties in re-establishing themselves after right-wing dictatorships were toppled in Portugal and Spain, respectively in 1974 and 1975. Until its 1976 congress in Geneva, the Socialist International had few members outside Europe and no formal involvement with Latin America. In the United States, the Social Democrats, USA, an association of reformist social democrats and democratic socialists, was founded in 1972. The Socialist Party of America had stopped running independent presidential candidates and begun reforming itself towards democratic socialism. Consequently, the party's name was changed because it had confused the public. With the name change in place, the Social Democrats, USA clarified its vision to Americans who confused democratic socialism with Marxism–Leninism, harshly opposed by the organisation.
Pharmacology has become increasingly sophisticated; modern biotechnology allows drugs targeted towards specific physiological processes to be developed, sometimes designed for compatibility with the body to reduce side-effects. Genomics and knowledge of human genetics and human evolution is having increasingly significant influence on medicine, as the causative genes of most monogenic genetic disorders have now been identified, and the development of techniques in molecular biology, evolution, and genetics are influencing medical technology, practice and decision-making. Evidence-based medicine is a contemporary movement to establish the most effective algorithms of practice (ways of doing things) through the use of systematic reviews and meta-analysis. The movement is facilitated by modern global information science, which allows as much of the available evidence as possible to be collected and analyzed according to standard protocols that are then disseminated to healthcare providers. The Cochrane Collaboration leads this movement. A 2001 review of 160 Cochrane systematic reviews revealed that, according to two readers, 21.3% of the reviews concluded insufficient evidence, 20% concluded evidence of no effect, and 22.5% concluded positive effect.
=== Characterization and analysis === Esters are generally identified by gas chromatography, taking advantage of their volatility. IR spectra for esters feature an intense sharp band in the range 1730–1750 cm−1 assigned to νC=O. This peak changes depending on the functional groups attached to the carbonyl. For example, a benzene ring or double bond in conjunction with the carbonyl will bring the wavenumber down about 30 cm−1.
The trade and Hong Kong concessions were a result of the 1841 Convention of Chuenpi (signed by Qishan and Charles Elliot and the 1842 Treaty of Nanking (signed by Henry Pottinger, Keying, and Yilibu). The opium trade incurred intense enmity from the later British Prime Minister William Ewart Gladstone. As a member of Parliament, Gladstone called it "most infamous and atrocious" referring to the opium trade between China and British India in particular. Gladstone was fiercely against both of the Opium Wars Britain waged in China in the First Opium War initiated in 1840 and the Second Opium War initiated in 1857, denounced British violence against Chinese, and was ardently opposed to the British trade in opium to China. Gladstone lambasted it as "Palmerston's Opium War" and said that he felt "in dread of the judgments of God upon England for our national iniquity towards China" in May 1840. A famous speech was made by Gladstone in Parliament against the First Opium War. Gladstone criticized it as "a war more unjust in its origin, a war more calculated in its progress to cover this country with permanent disgrace". His hostility to opium stemmed from the effects of opium brought upon his sister Helen. Due to the First Opium war brought on by Palmerston, there was initial reluctance to join the government of Peel on part of Gladstone before 1841.
Sources: en.wikipedia.org
It is a modified version of the natural hormone, with three amino acid changes and a fatty acid side chain added. These edits extend its half-life from minutes to about one week. The core receptor activity is retained.
Both deliver the same active peptide and act on the same receptor. The tablet includes an absorption enhancer because peptides are poorly taken up intact from the gut. Bioavailability of the oral route is substantially lower, so the two are not dose-equivalent.
No, it is entirely synthetic and does not occur in nature. Native GLP-1 is produced in the gut and pancreas, but the analog is manufactured by chemical synthesis or recombinant methods. Traces of the analog are not expected in people who never received it.
Long-term storage is usually at minus 20 to minus 80 degrees Celsius in a sealed, desiccated container. Working aliquots can be held briefly at 2 to 8 degrees Celsius.