This is a working overview of 稳定性, written for readers who want more than a one-paragraph summary but less than a textbook.
Reviewed 2026-03-02. Anything still debated is marked as such rather than presented as settled.
At the receptor level, tirzepatide activates both the glucose-dependent insulinotropic polypeptide receptor and the glucagon-like peptide-1 receptor. Both belong to the class B family of G protein-coupled receptors and signal largely through cyclic AMP accumulation. The compound binds the two receptors with differing affinity, and the pattern of signaling at each site is described in the literature as biased rather than simply proportional to occupancy. Tissues carrying these receptors include pancreatic islets, adipose tissue, the central nervous system, and the gastrointestinal tract. The relative weight of each receptor population in producing metabolic effects continues to be studied.
Published work supports the view that engaging two incretin receptors produces changes in glucose handling and body weight larger than those seen with single-receptor activation. Why that difference arises is not fully settled. Open questions include how much of the observed weight effect depends on central versus peripheral signaling, and whether the two receptors form interacting complexes. Most reported findings come from controlled trials and animal models, and translation between species is imperfect. Further research is expected to refine these points over time.
Regulatory and quality discussions place the peptide within established guidance for synthetic peptides and biologics. Forced degradation studies, in which samples are exposed to heat, acid, base, peroxide, and light, identify likely degradation products and validate the selectivity of analytical methods. Reference standards allow comparison across laboratories and production batches. Purity specifications reported in the literature usually combine chromatographic purity with mass confirmation. Which impurity thresholds are meaningful for long-term behavior is still debated, and no single universal specification has been adopted across all jurisdictions.
Routine characterization of the peptide relies on reversed-phase high-performance liquid chromatography for purity assessment, usually with ultraviolet detection near 214 nanometers. Intact mass measurement by liquid chromatography coupled to mass spectrometry confirms molecular identity against a theoretical value. Sequence-level confirmation uses enzymatic digestion followed by tandem mass spectrometry, an approach known as peptide mapping. Amino acid analysis gives an independent check on composition. Circular dichroism spectra are used to estimate helical content in aqueous buffer.
| Property | Value | Notes |
|---|---|---|
| Molecular formula | C225H348N48O68 | 39-residue synthetic peptide |
| Average molecular mass | About 4813.5 Da | Free base form |
| Appearance | White to off-white powder | Solid after lyophilization |
| Solubility class | Freely soluble in water | Also soluble in neutral aqueous buffers |
| Typical storage | At or below -20 °C, desiccated | Protect from light and moisture |
当前公开资料把 tirzepatide 归为肠促胰素类受体双重激动剂。它并非激素天然变体，而是经过序列改造的工程化肽。其分子量、等电点与疏水性等基础参数已在药典和化学数据库中收录，可作为分析检测和质量研究的参照。
Tirzepatide 是一种由 39 个氨基酸组成的合成肽，分子结构上以 GIP 序列为骨架并引入脂肪酸侧链修饰，使其能够同时与葡萄糖依赖性促胰岛素多肽（GIP）受体和胰高血糖素样肽-1（GLP-1）受体结合。这种双重激动特性使它在同类肽类药物中区别于选择性 GLP-1 受体激动剂。该分子最早由一家制药公司在 2010 年代报道，随后进入糖尿病与体重管理领域的临床研究。
定量分析的主流方法是反相高效液相色谱联用紫外或质谱检测，利用肽在疏水固定相上的保留行为确定纯度与含量。对于生物基质中的浓度测定，常采用液相色谱串联质谱，并配合固相萃取或蛋白沉淀进行样品前处理。免疫分析法也可使用，但可能受到结构相关肽的交叉反应干扰。
纯度评估通常综合反相色谱、体积排阻色谱与质谱三方面信息：前者反映疏水性杂质，后者反映聚集体，质谱则确认分子量与主要降解产物。有关降解途径的完整图谱——例如脱酰胺、氧化与水解各占多大比例——在不同储存条件下仍有差异，属于需要逐案验证的问题。
质量控制环节关注外观、含量、纯度、有关物质、水分与微生物限度等项目。检测结果需要有对照品和系统适用性数据支持，单次测定不足以判定批次的稳定性。实验室之间方法转移时，色谱柱品牌与梯度差异常导致保留时间漂移，因此方法验证十分必要。
Tirzepatide is a synthetic peptide composed of 39 amino acids. It acts as a dual agonist at two incretin receptors, the glucose-dependent insulinotropic polypeptide receptor and the glucagon-like peptide-1 receptor. The molecule was designed by modifying the native sequence of glucose-dependent insulinotropic polypeptide to improve metabolic stability and extend its circulation time. Its structure includes several non-natural amino acid residues and a fatty acid side chain. These features distinguish it from earlier single-receptor incretin analogs studied in the same period.
The compound first appeared in the scientific literature as an investigational agent for type 2 diabetes. Clinical development proceeded through phase 1, phase 2, and phase 3 programs that measured glycemic control as a primary endpoint while recording body weight as a secondary outcome. Regulatory approval in the United States followed in 2022 for glycemic control, and a separate indication for chronic weight management was added later. Subsequent trials have examined cardiovascular outcomes in adults with elevated cardiovascular risk. Debates continue over how much of the observed effect derives from each receptor arm.
== See also == List of investigational drugs List of investigational generalized anxiety disorder drugs List of investigational panic disorder drugs List of investigational post-traumatic stress disorder drugs List of investigational anxiety disorder drugs List of investigational autism and pervasive developmental disorder drugs List of investigational aggression drugs
In any case, findings that bicalutamide helps to preserve body weight and lean body mass in castrated male rats also could not be explained by preservation of estrogen levels. Aside from muscle, bicalutamide has also been found to act not as an AR silent antagonist but as a weak partial agonist of the receptor with SARM-like activity in AR-positive MDA-MB-453 breast cancer cells. Whereas a pure AR antagonist should have no effect, bicalutamide regulated almost 50% of 189 DHT-responsive genes in this cell line and induced these genes around 25% as effectively as the highest tested concentration of DHT. DHT and SARMs like enobosarm and GTx-027 inhibit the proliferation of AR-expressing MDA-MB-231 breast cancer cells, whereas findings for bicalutamide are conflicting. Bicalutamide has also shown SARM-like or weak partial agonist activity in certain other in vitro AR bioassays. A very high (50 mg/kg) dose of bicalutamide has been found to suppress testosterone levels by about 91% in gonadally intact male mice, which was to a similar degree as the SARM MK-4541. These findings suggest that bicalutamide at very high doses may have antigonadotropic effects that may be mediated by SARM-like activity. Conversely however, lower doses of bicalutamide (1–25 mg/kg) have not been found to affect testosterone levels in gonadally intact male rats, and similar or higher doses of bicalutamide (20–100 mg/kg) did not affect testosterone levels in gonadally intact male dogs.
Illegal drugs can be counterfeited easily because no standards or regulations govern them or their packaging though some examples of illegal drugs are sold under "brand names" to indicate certain standards or dosage levels were being adhered to, as in the case of 1960s-era LSD, which was sold with patterns or logos printed on blotter paper. These illegal "brands" can also be counterfeited by drug dealers who want to be able to sell their products at higher prices. Counterfeit illegal and recreational drugs range from products which do not contain any active ingredients, as in cases where lactose powder is sold as heroin, or dried herbs such as oregano are sold as cannabis, to cases where the active ingredients are "cut" with a diluent (as in cases where cocaine is mixed with lactose powder), and cases where the claimed active ingredients are substituted by something cheaper (e.g., when methamphetamine is sold as cocaine). The use of diluents in illegal drugs reduces the potency of the drugs and makes it hard for users to determine the appropriate dosage level. Diluents include "foodstuffs (flour and baby milk formula), sugars (glucose, lactose, maltose, and mannitol), and inorganic materials such as powder." The diluents used, often depend on the way drug purchasers consume particular drugs. Drug dealers selling heroin to users who inject, dilute the drug with different products from dealers selling to users who smoke, or insufflate the drug. Diluents which can easily form a solution with water for injecting heroin can be problematic for users who are sniffing the powder.
Alpha synuclein, having no single, well-defined tertiary structure, is an intrinsically disordered protein, with a pI value of 4.7, which, under certain pathological conditions, can misfold in a way that exposes its core hydrophobic residues to the intracellular milieu, thus providing the opportunity for hydrophobic interactions to occur with a similar, equally exposed protein. This could lead to self assembly and subsequent aggregation into large, insoluble fibrils known as amyloids. The conversion of soluble alpha synuclein into highly ordered, cross-β sheet, fibrillar structures does not, as previously thought, follow a two-step mechanism, rather, occurs through a series of transient, soluble oligomeric intermediates. In 2011, two groups published their findings that unmutated α-synuclein forms a stably folded tetramer that resists aggregation, asserting that this folded tetramer represented the relevant in vivo structure in cells, thereby relieving alpha synuclein of its disordered status. Proponents of the tetramer hypothesis argued that in vivo cross-linking in bacteria, primary neurons and human erythroleukemia cells confirmed the presence of labile, tetrameric species. However, despite numerous in-cell NMR reports demonstrating that alpha synuclein is indeed monomeric and disordered in intact E. coli cells, it is still a matter of debate in the field despite an ever growing mountain of conflicting reports.
While giving evidence under oath, former Post Office chairman Henry Staunton tells a parliamentary hearing on the Horizon IT scandal that current Post Office chair Nick Read is under internal investigation. 28 February The Duke of Sussex loses a High Court challenge against the UK government's decision to downgrade his security status when he stopped being a working royal. A study in the British Medical Journal links ultra-processed foods to 32 negative health impacts, including a higher risk of heart disease, cancer, type 2 diabetes, adverse mental health and early death. Following a trial at the High Court in Glasgow, Iain Packer is found guilty of the April 2005 murder of Emma Caldwell, a sex worker whose body was found in woods five weeks after she disappeared from Glasgow. Packer, who is also convicted of 32 other offences against women, including rapes and sexual assaults, is sentenced to at least 36 years in prison, the second longest prison sentence to be handed out by a Scottish court. 29 February 2024 Rochdale by-election: In an unusually chaotic by-election, former MP George Galloway resoundingly wins for the Workers Party of Britain, marking his return to parliament. Independent candidate David Tully comes second, with the Conservative candidate Paul Ellison coming third. Both the Labour and Green Party candidates were disowned by their respective parties. Angiolini Inquiry: The public inquiry into the murder of Sarah Everard finds that her killer Wayne Couzens should never have been a police officer, and that opportunities to detect his offending were missed.
Sources: en.wikipedia.org
Actin, alpha 1 Actinin, alpha 1 Adaptor-related protein complex 2, alpha 1 Aldehyde dehydrogenase 3 family, member A1 Aldehyde dehydrogenase 4 family, member A1 Aldehyde dehydrogenase 5 family, member A1 Aldehyde dehydrogenase 6 family, member A1 Aldehyde dehydrogenase 9 family, member A1 Aldehyde dehydrogenase 18 family, member A1 Aldo-keto reductase family 1, member A1 Alpha-1-microglobulin/bikunin precursor Apolipoprotein A1 and ApoA-1 Milano ATPase, H+ transporting, lysosomal V0 subunit a1 ATPase, Na+/K+ transporting, alpha 1 ATP synthase, H+ transporting, mitochondrial F1 complex, alpha 1 BCL2-related protein A1 Butyrophilin, subfamily 1, member A1 Butyrophilin, subfamily 3, member A1 Capping protein (actin filament) muscle Z-line, alpha 1 Carboxypeptidase A1 Casein kinase 1, alpha 1 Casein kinase 2, alpha 1 Catenin (cadherin-associated protein), alpha 1 Centaurin, alpha 1 Cholinergic receptor, nicotinic, alpha 1 Coagulation factor XIII, A1 polypeptide collagen, type I, alpha 1 collagen, type II, alpha 1 Collagen, type III, alpha 1 Collagen, type IV, alpha 1 Collagen, type V, alpha 1 Collagen, type VI, alpha 1 Collagen, type VII, alpha 1 Collagen, type VIII, alpha 1 Collagen, type IX, alpha 1 Collagen, type X, alpha 1 Collagen, type XI, alpha 1 Collagen, type XII, alpha 1 Collagen, type XIII, alpha 1 Collagen, type XIV, alpha 1 Collagen, type XV, alpha 1 Collagen, type XVI, alpha 1 Collagen, type XVII, alpha 1 Collagen, type XVIII, alpha 1 Collagen, type XIX, alpha 1 Collagen, type XXV, alpha 1 Collagen, type XXVII, alpha 1 Crystallin, beta A1 Cyclic nucleotide-gated channel alpha 1 Cyclin A1 Cytochrome P450, family 1, member A1 Defensin, alpha 1 Dystrophin-associated protein A1 Ephrin A1 Eukaryotic translation elongation factor 1 alpha 1 Family with sequence similarity 13, member A1 Family with sequence similarity 19 (chemokine (C-C motif)-like), member A1 Gamma-aminobutyric acid (GABA) A receptor, alpha 1 Gap junction protein, alpha 1 GDNF family receptor alpha 1 Glutathione S-transferase A1 Glycine receptor, alpha 1 Heat shock protein 90kDa alpha (cytosolic), member A1 Hemoglobin, alpha 1 Heterogeneous nuclear ribonucleoprotein A1 Homeobox A1 Immunoglobulin heavy constant alpha 1 Importin alpha 1 Interferon, alpha 1 Interleukin 13 receptor, alpha 1 Karyopherin alpha 1 Laminin, alpha 1 Major histocompatibility complex, class II, DP alpha 1 Major histocompatibility complex, class II, DQ alpha 1 Myosin light chain A1, an actin-binding protein NADH dehydrogenase (ubiquinone), alpha 1 Nucleolar protein, member A1 PCDHA4 Phospholipase A1 Phosphorylase kinase, alpha 1 Plexin A1 Polymerase (DNA directed), alpha 1 Potassium large conductance calcium-activated channel, subfamily M, alpha 1 Proteasome (prosome, macropain) subunit, alpha 1 Protein kinase, AMP-activated, alpha 1 Protein tyrosine phosphatase, receptor type, f polypeptide (PTPRF), interacting protein (liprin), alpha 1 Protocadherin alpha 1 Pulmonary surfactant-associated protein A1 Pyruvate dehydrogenase (lipoamide) alpha 1 RNA binding motif protein, Y-linked, family 1, member A1 Replication protein A1 S100 calcium binding protein A1 Sec61 alpha 1 Serum amyloid A1 Solute carrier family 35 (CMP-sialic acid transporter), member A1 Spectrin, alpha 1 Sperm protein associated with the nucleus, X-linked, family member A1 Syntrophin, alpha 1 Transient receptor potential cation channel, member A1 UDP glucuronosyltransferase 1 family, polypeptide A1 Urea Transporter A1 a gene found in the maize encoding for the dihydroflavonol 4-reductase (reducing dihydroflavonols into flavan-4-ols) in the phlobaphene metabolic pathway proteins
== Clinical trials == Sulanemadlin is notable as the first stapled peptide, a novel pharmaceutical strategy, to enter clinical trials. Despite its preclinical promise, concerns about side effects, including severe neutropenia, have terminated Phase 1B clinical trials early in at least one trial.
Camptocormia, also known as bent spine syndrome (BSS), is a symptom of a multitude of diseases that is most commonly seen in the elderly. It is identified by an abnormal thoracolumbar spinal flexion, which is a forward bending of the lower joints of the spine, occurring in a standing position. In order to be classified as BSS, the anterior flexion (the lower back bending) must reach 45 degrees anteriorly. This classification differentiates it from a similar syndrome known as kyphosis. Although camptocormia is a symptom of many diseases, there are two common origins: neurological and muscular. Camptocormia is treated by alleviating the underlying condition causing it through therapeutic measures or lifestyle changes.
In road transport, the Emission Performance Regulation 2019 says manufacturers of "new passenger cars" should not allow emissions to exceed 95 grams of CO2 per kilometre, and 147 grams of CO2 per kilometre for new light commercial vehicles, but this is merely an "EU fleet-wide target" rather than requirements for each vehicle. Manufacturers can agree to pool their production quotas, so as to meet their targets on average, but there is no legal sanction for failure to meet the target. Member states are simply required to record the relevant success or failure, and manufacturers' performance is published. By contrast the Vehicles Emissions Regulation 2007 sets the "Euro 6" standards in maximum emissions that car manufacturers can have. Since the 'Euro 1' standard was introduced in 1992, standards became cleaner each 4 to 5 years, but recently stalled. Article 2 states this applies to vehicles under 2,610 kilograms, while the Heavy Vehicle Emission Regulation 2019 applies to heavier vehicles, with looser CO2 limits. Article 4 states manufacturers must 'demonstrate that all new vehicles sold, registered or put into service in the Community are type approved in accordance with this Regulation'. Article 6 requires manufacturers to 'provide unrestricted and standardised access to vehicle repair and maintenance information' should there be any non-compliance. Article 13 requires penalties imposed by member states for breach are 'effective, proportionate and dissuasive', and breaches include any 'false declarations' as well as 'use of defeat devices'.
In January 2023, Vice President Geraldo Alckmin met with Vice President Frans Timmermans of the EU Commission in Brasília. During his visit to Brazil, Timmermans said that President Lula's efforts to end destruction in the Amazon deserves support and cooperation from the European Union, adding that the EU could donate up to €750,000 to help the Yanomami people facing a humanitarian crisis. In March 2023, the EU's commissioner for competition Margrethe Vestager met with Vice President Alckmin and other Brazilian officials during a meeting in Brasília to unveil the EU-Brazil bilateral Investment Map. In June 2023, Lula met with EU president Ursula von der Leyen to discuss areas such as environment, science and technology and trade, namely the EU-Mercosur trade deal. Lula expressed concerns over a European Union's side letter proposal of sanctioning Mercosur goods in case they fail to meet environmental goals saying that "between partners there should be mutual confidence not mistrust and sanctions" and that the sanctions could hurt genuine Brazilian green efforts. During the meeting the European Union pledged to donate 20 million euros to the Amazon Fund. In July 2023, numerous Latin American, Caribbean and European leaders, including Lula, attended the III EU-CELAC summit in Brussels to discuss topics such as global hunger, inequalities, poverty and climate change. On the sidelines of the summit, Lula made the case for the EU-Mercosur trade deal and expressed concern for protectionist policies in the agreement.
Sources: en.wikipedia.org
This occurred due to DOM being publicly distributed for free in the form of high-dose tablets by LSD distributor Owsley Stanley, who had personally learned of DOM from Shulgin. It is unclear why Shulgin provided information about DOM to Stanley, since doing so had the potential to risk Shulgin's professional career and the DOET clinical studies. One possibility is that Dow Chemical Company was not further looking into DOM and Shulgin thought that it was a promising drug that would otherwise be forgotten. In any case, street use of DOM was short-lived because the tablets caused a public health crisis due to them often producing very long durations (up to 3–4 days), intense experiences, worrying physical side effects, and hospitalizations. DOM was first reported on in the media and scientific literature in 1967 as a result of the crisis. DOM became illegal in the United States in 1968. Dow Chemical Company terminated its clinical research program on DOET due to the DOM public health crisis. DOET was subsequently first described in the literature by Snyder and colleagues in 1968. Snyder continued to be interested in DOET as a potential medicine, but it was never further developed. Snyder also described 2,5-dimethoxyamphetamine (2,5-DMA), which had been synthesized and tested by Shulgin, in the literature in 1968. DOM and DOET were further described in the scientific literature by Shulgin in 1969. In addition, Shulgin discussed DOM, DOET, TMA-2, and 2,5-DMA in a book chapter on hallucinogens published in 1970.
== Human exposure == A person can be exposed to uranium (or its radioactive daughters, such as radon) by inhaling dust in air or by ingesting contaminated water and food. The amount of uranium in air is usually very small; however, people who work in factories that process phosphate fertilizers containing uranium impurities, live near government facilities that made or tested nuclear weapons, live or work near a modern battlefield where depleted uranium weapons have been used, or live or work near a coal-fired power plant, facilities that mine or process uranium ore, or enrich uranium for reactor fuel, may have increased exposure to uranium. Houses or structures that are over uranium deposits (either natural or man-made slag deposits) may have an increased incidence of exposure to radon gas. The health impacts of natural and of depleted uranium are chemical rather than due to radiation. The Occupational Safety and Health Administration (OSHA) has set the permissible exposure limit for uranium exposure in the workplace as 0.25 mg/m3 over an 8-hour workday. The National Institute for Occupational Safety and Health (NIOSH) has set a recommended exposure limit (REL) of 0.2 mg/m3 over an 8-hour workday and a short-term limit of 0.6 mg/m3. At 10 mg/m3, uranium is immediately dangerous to life and health. Most ingested uranium is excreted during digestion. Only 0.5% is absorbed when insoluble forms of uranium, such as its oxide, are ingested, whereas absorption of the more soluble uranyl ion can be up to 5%.
=== European Union === The European Union-funded project SYNBIOSAFE has issued reports on how to manage synthetic biology. A 2007 paper identified key issues in safety, security, ethics, and the science-society interface, which the project defined as public education and ongoing dialogue among scientists, businesses, government and ethicists. The key security issues that SYNBIOSAFE identified involved engaging companies that sell synthetic DNA and the biohacking community of amateur biologists. Key ethical issues concerned the creation of new life forms. A subsequent report focused on biosecurity, especially the so-called dual-use challenge. For example, while synthetic biology may lead to more efficient production of medical treatments, it may also lead to synthesis or modification of harmful pathogens (e.g., smallpox). The biohacking community remains a source of special concern, as the distributed and diffuse nature of open-source biotechnology makes it difficult to track, regulate or mitigate potential concerns over biosafety and biosecurity. COSY, another European initiative, focuses on public perception and communication. To better communicate synthetic biology and its societal ramifications to a broader public, COSY and SYNBIOSAFE published SYNBIOSAFE, a 38-minute documentary film, in October 2009. The International Association Synthetic Biology has proposed self-regulation. This proposes specific measures that the synthetic biology industry, especially DNA synthesis companies, should implement.
Adam LeBor (1961); author, journalist; foreign correspondent from 1991; now based in London; also lived in Ramat HaShofet kibbutz, Israel, Berlin and Paris; reported from the former Yugoslavia; covered collapse of Communism and Yugoslav wars for The Independent ;currently contributes to The Times, the Financial Times, where he reviews thrillers, The Critic, Monocle; works as editorial trainer and writing coach at Financial Times, Citywire and Monocle; former contributor to Harry's Place; has written eight non-fiction books, including Hitler's Secret Bankers, shortlisted for the Orwell Prize, a biography of Slobodan Milosevic, and City of Oranges, an account of Jewish and Arab families in Jaffa, shortlisted for the Jewish Quarterly Prize. Sir Sidney Lee (1859–1926), biographer and literary scholar Joseph Leftwich, writer, one of the Whitechapel Boys Antony Lerman (born 11 March 1946); author advocating One-state solution in Israel and Palestine; critic of the concept of the New antisemitism; explores meaning of Zionism and Anti-Zionism; from 2006 to early 2009, was Director of the Institute for Jewish Policy Research. David Levi, writer on Jewish subjects Amy Levy (10 November 1861 – 9 September 1889) was an English essayist, poet, and novelist best remembered for her literary gifts; her experience as the second Jewish woman at Cambridge University, and as the first Jewish student at Newnham College, Cambridge.
Sources: en.wikipedia.org
It is a synthetic peptide and a dual agonist of two incretin receptors. It is not a small molecule, and it is not structurally related to the older single-receptor peptide agonists.
The C20 fatty diacid promotes tight binding to serum albumin. That binding reduces renal clearance and extends circulation time compared with an unmodified peptide of similar length.
It is not fully established. Studies indicate that both receptors contribute to the observed effects, but the exact split between the two signaling pathways in humans remains an open question.
Peptide mapping with tandem mass spectrometry is the standard approach. The peptide is digested with an enzyme such as trypsin, and the resulting fragments are matched against the expected sequence.