The short version of incretin mimetic fits in a sentence. The long version — which is the one that helps — is below.
This page was last updated on 2026-02-14 and is reviewed periodically as new material appears.
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.
Semaglutide belongs to the glucagon-like peptide-1 receptor agonist class, a group of synthetic peptides that imitate an incretin hormone released by intestinal L cells after food intake. Native GLP-1 circulates for only a few minutes because dipeptidyl peptidase-4 cleaves it rapidly. The hormone acts on pancreatic islets, the gastrointestinal tract, and several brain regions. Because the natural peptide is short-lived, development work concentrated on analogues that keep receptor activity while resisting enzymatic breakdown and renal clearance.
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.
Semaglutide is a synthetic peptide that acts as an agonist at the glucagon-like peptide-1 receptor. It is a structural analogue of human GLP-1(7-37), modified to resist enzymatic degradation by dipeptidyl peptidase-4. The peptide backbone contains alpha-aminoisobutyric acid at position 8, a substitution that stabilises the helix and slows cleavage. A fatty diacid side chain attached through a linker at lysine 34 promotes binding to serum albumin, which extends the circulating half-life. These two modifications together allow less frequent administration than native GLP-1 requires.
Activation of the GLP-1 receptor couples to Gs signalling and raises intracellular cyclic AMP in pancreatic beta cells. The resulting insulin release depends on prevailing glucose concentrations, so the effect is greater when glucose is elevated. Receptor engagement also suppresses glucagon secretion and slows gastric emptying, which flattens post-meal glucose excursions. In the central nervous system, signalling in hypothalamic and brainstem regions is associated with reduced appetite and lower energy intake. Studies continue to examine effects on cardiac, renal and hepatic endpoints; whether those benefits are independent of weight change remains an open question.
| Property | Value | Notes |
|---|---|---|
| Molecular class | Synthetic peptide, GLP-1 receptor agonist | 31 amino acid residues |
| Molecular formula | C187H291N45O59 | free peptide, no counter-ion |
| Approximate mass | 4114 Da | matches theoretical value |
| Receptor target | Glucagon-like peptide-1 receptor | Gs-coupled, cyclic AMP pathway |
| Circulation half-life | About one week in humans | extended by albumin association |
皮下注射后吸收相对缓慢，绝对生物利用度约为百分之八十九，血药浓度峰值通常出现在给药后一到三天。与白蛋白结合使清除减慢，终末半衰期约为一百六十五小时，接近一周。连续给药约四到五周后达到稳态暴露水平。表观分布容积约为每千克零点二五升，血浆蛋白结合率超过百分之九十九。代谢以蛋白水解切割和脂肪二酸侧链的 β-氧化为主，相关产物主要经尿液与粪便排出。
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。
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.
Semaglutide dissolves readily in water and in aqueous buffers near neutral pH. Solubility decreases near the isoelectric point, where net charge is minimal. Common laboratory solvents include phosphate-buffered saline and dilute ammonium bicarbonate. Strongly acidic or basic conditions may accelerate hydrolysis. Working concentrations are usually prepared by diluting a concentrated stock. Vial surfaces can adsorb small amounts of peptide at low concentrations, so carrier proteins or low-binding tubes are sometimes used.
Stability studies examine how temperature, pH, and moisture influence degradation rates over time. In aqueous solution, hydrolysis and deamidation accelerate as pH moves away from mildly acidic conditions. Light exposure and residual metal ions can also trigger oxidation of susceptible residues. Accelerated aging at elevated temperature is used to estimate shelf life, though extrapolation to room temperature carries uncertainty because individual degradation pathways do not always scale predictably.
Lyophilized semaglutide powder is typically held at minus twenty degrees Celsius for long-term storage. At that temperature, solid-state degradation reactions proceed slowly and the peptide remains intact for extended periods. Repeated freeze-thaw cycles are best avoided because they promote aggregation and can shift the proportion of monomeric peptide present. Working aliquots are often prepared so that each portion is thawed only once, and desiccant is placed inside the vial to limit moisture uptake.
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.
Immediate-release oxycodone (OxyFast, OxyIR, OxyNorm, Roxicodone, Shortec) Controlled-release oxycodone (OxyContin, Xtampza ER, Oxypro) – 10–12 hour duration Oxycodone tamper-resistant (OxyContin OTR) Immediate-release oxycodone with paracetamol (acetaminophen) (Percocet, Endocet, Roxicet, Tylox) Immediate-release oxycodone with aspirin (Endodan, Oxycodan, Percodan, Roxiprin) Immediate-release oxycodone with ibuprofen (Combunox) Controlled-release oxycodone with naloxone (Targin, Targiniq, Targinact) – 10–12 hour duration Controlled-release oxycodone with naltrexone (Troxyca) – 10–12 hour duration
Israel say the refusal was because they intended to spread hate speech against Israel. Elin Jones confirms she will stand down as Llywydd of the Senedd following the next election. 8 April – Downing Street declines calls to officially back a campaign to buy British goods in the wake of the introduction of US trade tariffs, arguing that the UK is "an open-trading nation" and the government is "not going to tell people where they buy their stuff". The European Court of Human Rights rules that businessman Sir Philip Green's human rights were not breached when he was named in the House of Lords in relation to misconduct allegations in 2018. He was named in Parliament under the rule of Parliamentary privilege, which allows Members of Parliament and peers to speak without the threat of legal repercussions. 9 April King Charles gives a speech to the Italian Parliament. He and Queen Camilla also have a private meeting with Pope Francis at Vatican City. Leader of the Fire Brigades Union Steve Wright calls on Labour MPs to reject benefit cuts. Councillor for Talbot and Branksome Woods on Bournemouth, Christchurch and Poole Council Karen Rampton resigns from the Conservative Party. The Welsh Government confirms that the Senedd will vote on whether the Terminally Ill Adults (End of Life) Bill should apply to Wales if it successfully passes through the Westminster parliament. 10 April – The Cabinet Office is to lose a third of its posts as part of government reforms to the civil service, with 2,100 of the 6,500 positions to be cut.
Often described as a de facto one-party state because of its uncommon longevity for a nominal liberal democracy, some activists and opposition politicians view the PAP government's tight regulation of political and media activities, along with its stringent laws, as an infringement on political rights. In response, the PAP introduced several significant political changes, including the creation of the Non-constituency Members of Parliament (NCMPs) scheme from the 1984 election, which allowed a limited number of the best performing losing opposition candidates to be appointed as MPs. Group representation constituencies (GRCs) were subsequently introduced in the 1988 election as multi-member electoral divisions intended to guarantee minority representation in parliament, although the opposition has accused the scheme of enabling gerrymandering. In addition, Nominated Members of Parliament (NMPs) were introduced in 1990 to allow non-elected and non-partisan representatives from diverse professional fields to serve in parliament. The constitution was amended in 1991 to provide for an elected president with veto powers over the use of past reserves and key public service appointments. The first such election was held in 1993. In 1990, Goh Chok Tong succeeded Lee and became Singapore's second prime minister, leading the PAP into the 1991 election. During Goh's tenure, the country went through the 1997 Asian financial crisis and the 2002–2004 SARS outbreak. In 2004, Lee Hsien Loong, the eldest son of Lee Kuan Yew, became the country's third prime minister.
Sources: en.wikipedia.org
Because the Apollo 13 Moon landing was aborted, its RTG rests in the South Pacific Ocean, in the vicinity of the Tonga Trench. The Curiosity and Perseverance Mars rover designs selected RTGs to allow greater flexibility in landing sites and longer lifespan than the solar-powered option, as used in prior generations of rovers. RTGs were also used for the Nimbus, Transit and LES satellites. By comparison, only a few space vehicles have been launched using full-fledged nuclear reactors: the Soviet RORSAT series and the American SNAP-10A. In addition to spacecraft, the Soviet Union built 1,007 RTGs to power uncrewed lighthouses and navigation beacons on the Soviet Arctic coast by the late 1980s. Many different types of RTGs (including Beta-M type) were built in the Soviet Union for a wide variety of purposes. The lighthouses were not maintained for many years after the dissolution of the Soviet Union in 1991. Some of the RTG units disappeared during this time—either by looting or by the natural forces of ice/storm/sea. In 1996, a project was begun by Russian and international supporters to decommission the RTGs in the lighthouses, and by 2021, all RTGs had been removed. As of 1992, the United States Air Force also used RTGs to power remotely-located Arctic equipment, and the US government has used hundreds of such units to power remote stations globally. Sensing stations for Top-ROCC and SEEK IGLOO radar systems, predominantly located in Alaska, use RTGs.
(CH2CH2)O + HCl → HO–CH2CH2–Cl The reaction with these acids competes with the acid-catalyzed hydration of ethylene oxide; therefore, there is always a by-product of ethylene glycol with an admixture of diethylene glycol. For a cleaner product, the reaction is conducted in the gas phase or in an organic solvent. Ethylene fluorohydrin is obtained differently, by boiling hydrogen fluoride with a 5–6% solution of ethylene oxide in diethyl ether. The ether normally has a water content of 1.5–2%; in absence of water, ethylene oxide polymerizes. Halohydrins can also be obtained by passing ethylene oxide through aqueous solutions of metal halides:
Rosalyn Higgins, Baroness Higgins (born 2 June 1937); author of several influential works on international law, including Problems and Process: International Law and How We Use It (1994); former president of International Court of Justice (ICJ); was first female judge elected to the ICJ, and was elected to three-year term as president in 2006; became Queen's Counsel (QC) in 1986, and is bencher of the Inner Temple; served on the UN Human Rights Committee for 14 years; resigned from the Human Rights Committee when she was elected to the International Court of Justice on 12 July 1995, re-elected on 6 February 2000, and ended her second term on 6 February 2009. Her professional appointments include Specialist in International Law, Royal Institute of International Affairs, 1963–1974; Visiting Fellow, London School of Economics, 1974–1978;Professor of International Law, University of Kent at Canterbury, 1978–1981; Professor of International Law, University of London (London School of Economics), 1981–1995; Vice President, British Institute of International and Comparative Law; Member of the UN Human Rights Committee. David Hirsh (born 29 September 1967) author and scholar; professor in Sociology at Goldsmiths, University of London, and co-founder of Engage, a campaign against the academic boycott of Israel. Eric Hobsbawm Marxist historian of Viennese Jewish origin. Anthony Horowitz works include the Alex Rider series Eva Ibbotson (née Wiesner; 21 January 1925 – 20 October 2010) was an Austrian-born British novelist, known for her children's literature.
== Scientific references == Aller, Raymond D.; Salazar, Vincent (2016), "Microbiology Laboratory Information Systems", Manual of Commercial Methods in Clinical Microbiology, John Wiley & Sons, Inc, pp. 377–385, doi:10.1002/9781119021872.ch20, ISBN 978-1-119-02187-2 Burkhartsmeier, Gary (June 2007), "HIPAA: Where are we now", Research Gate, vol. 39, no. 6, p. 28, PMID 17691704 De Rienzo, Assunta; Cook, Robert W.; Wilkinson, Jeff; Gustafson, Corinne E.; Amin, Waqas; Johnson, Clare E.; Oelschlager, Kristen M.; Maetzold, Derek J.; Stone, John F.; Feldman, Michael D.; Becich, Michael J.; Yeap, Beow Y.; Richards, William G.; Bueno, Raphael (2017-01-01), "Validation of a Gene Expression Test for Mesothelioma Prognosis in Formalin-Fixed Paraffin-Embedded Tissues", The Journal of Molecular Diagnostics, 19 (1): 65–71, doi:10.1016/j.jmoldx.2016.07.011, PMC 5225306, PMID 27863259 Turgeon, Mary Louise (2015-02-10), "Linne & Ringsrud's Clinical Laboratory Science - E-Book: The Basics and Routine Techniques", Elsevier Health Sciences, ISBN 978-0-323-37061-5 "Association of Pathology Chairs", Academic Pathology. 5: 2374289518788096, vol. 5, 2018-07-09, doi:10.1177/2374289518788096, ISSN 2374-2895, PMC 6039897
Sources: en.wikipedia.org
TAB2 in turn serves as a beacon for the recruitment of MEKK1 which then dismisses the N-CoR complex and derepresses its target gene, in effect converting bicalutamide into an AR agonist. This mechanism does not rely on mutations in the LBD of the AR.
A polyprotic acid is a compound which may lose more than 1 proton. Stepwise dissociation constants are each defined for the loss of a single proton. The constant for dissociation of the first proton may be denoted as Ka1 and the constants for dissociation of successive protons as Ka2, etc. Phosphoric acid, H3PO4, is an example of a polyprotic acid as it can lose three protons.
==== Oligoarticular arthritis (Oligoarthritis) ==== Oligoarticular (or pauciarticular) JIA is the most common JIA subtype, and occurs when there are up to four joints involved during the first six months of disease. Two subtypes of oligoarticular arthritis exist: persistent oligoarthritis, where no more than four joints are affected throughout the whole disease course; and extended oligoarthritis, where more than four joints are affected after the first six months of disease. Patients in this subtype are often young, typically aged between 1 and 5 years, and are female preponderant. The most commonly involved joint is the knee, but other affected joints may include the ankles, wrists, elbows, and others. 50% of cases involve mono-arthritis, only involving the knee. The anti-nuclear antigen (ANA) is positive in up to 80% of patients with oligoarthritis and is associated with a higher risk of associated eye disease (uveitis), particularly in younger patients. There is no adult counterpart disease to oligoarticular JIA. The prefixes oligo- and pauci- mean 'few'.
Nitric acid (HNO3) is by far the most important and the most stable of the nitrogen oxoacids. It is one of the three most used acids (the other two being sulfuric acid and hydrochloric acid) and was first discovered by alchemists in the 13th century. It is made by the catalytic oxidation of ammonia to nitric oxide, which is oxidised to nitrogen dioxide, and then dissolved in water to give concentrated nitric acid. In the United States of America, over seven million tonnes of nitric acid are produced every year, most of which is used for nitrate production for fertilisers and explosives, among other uses. Anhydrous nitric acid may be made by distilling concentrated nitric acid with phosphorus pentoxide at low pressure in glass apparatus in the dark. It can only be made in the solid state, because upon melting it spontaneously decomposes to nitrogen dioxide, and liquid nitric acid undergoes self-ionisation to a larger extent than any other covalent liquid as follows:
Grand Master Filema Duarte then stripped former Grand Master Urquía Carreño of all his Masonic rights, and referred him to appear in front of the Supreme Court of Masonic Justice, so that they could review the case. On September 10, 2024, Urquía Carreño was then arrested and taken into custody by the National Revolutionary Police at Zanja y Dragones Police Station, the same police station which had launched the theft investigation on January 12. His official charge was the embezzlement of $MN754,410.54 and US$2,700. Urquía Carreño and Airam Cervera were given a travel limit by the Cuban government, prevented from leaving the island with any potential stolen cash. In 2025, Urquía Carreño gave an interview on a YouTube channel associated with the Cuban government in which he denied all wrongdoing, and reiterated his belief that Viñas Alonso was the leader of an anti-government conspiracy alongside Gerardo Cepero and Ángel Santiesteban to remove him from office. He insisted that everything had been orchestrated by this group, beginning with the theft and ending with Urquía Carreño's eventual resignation.
Sources: en.wikipedia.org
It is a synthetic peptide of 31 amino acids, built to resemble the natural incretin hormone GLP-1. Because of its size and composition it is handled analytically like other therapeutic peptides, using chromatographic and mass spectrometric methods rather than the techniques typical of small organic drugs.
The substitution at position 8 removes the site recognised by dipeptidyl peptidase-4, the enzyme that destroys the native hormone within minutes. The linked lipophilic chain then binds circulating albumin, which further limits access by degradative enzymes and reduces renal loss. Together these features lengthen the effective circulation time considerably.
It acts at the glucagon-like peptide-1 receptor, a G protein-coupled receptor that signals mainly through cyclic AMP. Activation is glucose dependent, meaning insulin release is stimulated more strongly when blood glucose is already elevated. Other tissues carrying the same receptor respond as well, which explains effects beyond glucose control.
It belongs to the incretin mimetic class and acts as a long-acting glucagon-like peptide-1 receptor agonist. The class includes several peptides with different half-lives and routes of administration.