If you have been reading about lyophilization and want a single page that covers the useful parts, this is it: definitions, context, how it is studied, and the questions that come up repeatedly.
Last reviewed on 2025-09-29. Where a claim depends on a specific study, the study is described rather than over-claimed.
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。
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.
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 |
|---|---|---|
| 分子式 | C187H291N45O59 | 按主链与 C18 二酸侧链计算 |
| 分子量 | 约 4113.6 道尔顿 | 游离碱形式，随反离子略有差异 |
| 外观 | 白色至类白色冻干粉末 | 具吸湿性，需干燥保存 |
| 溶解性 | 微溶于水，易溶于碱性缓冲液 | 溶解性随 pH 升高而改善 |
| 等电点 | 约 5.4 | 影响缓冲液选择与聚集倾向 |
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.
Identity and purity are usually assessed by reverse-phase high-performance liquid chromatography coupled to mass spectrometry. Retention time and observed mass are compared against a reference standard run under identical conditions. Impurity profiles reveal deamidation products, oxidized methionine variants, and truncated fragments that arise during synthesis or storage. Peptide mapping through enzymatic digestion confirms the primary sequence, while amino acid analysis offers an independent check on overall composition.
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.
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.
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.
Reported molecular weight is approximately 4113.6 daltons for the free base, and the peptide is supplied as a lyophilized powder or in buffered liquid form depending on the intended use. It is freely soluble in water when formulated with appropriate excipients, though the unconjugated peptide shows limited stability at neutral pH over long periods. Analytical characterization typically relies on reversed-phase high-performance liquid chromatography and mass spectrometry. Purity specifications for research-grade material commonly exceed ninety-five percent by area. Isotopic and impurity profiles differ between suppliers.
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 primary target is the GLP-1 receptor, a class B G protein-coupled receptor expressed on pancreatic beta cells, in the gut, and in several brain regions. Receptor activation raises intracellular cyclic AMP, which potentiates glucose-dependent insulin secretion and lowers glucagon release when blood glucose is elevated. Signalling in the hypothalamus and brainstem is associated with reduced appetite and slower gastric emptying. Because the insulinotropic effect depends on prevailing glucose levels, the hypoglycaemic risk of the peptide alone is described as low in most study settings. The relative contribution of peripheral and central actions remains an active research question.
Large randomised trials in adults with type 2 diabetes and in adults with obesity have reported reductions in body weight and improvements in several cardiovascular risk markers. One outcome trial found a lower incidence of major adverse cardiovascular events in participants with diabetes and established cardiovascular disease. Gastrointestinal effects such as nausea and vomiting are the most frequently reported adverse events and often diminish over time. Changes in lean body mass during weight loss are an area of ongoing investigation. Effects in adolescents and in pregnancy are less well characterised, and current labelling advises against use during pregnancy.
Label-free quantification is a method in mass spectrometry that aims to determine the relative amount of proteins in two or more biological samples. Unlike other methods for protein quantification, label-free quantification does not use a stable isotope containing compound to chemically bind to and thus label the protein.
=== Writing career === After writing several short stories, a novella and book reviews, his debut crime novel, Dead I Well May Be, was published by Scribner in 2003. The book was followed by two sequels in what would become to be known as the Michael Forsythe Trilogy. Alongside these, McKinty wrote the three books in his Lighthouse Trilogy, a series of science fiction young adult novels set in New York City, his native Ireland, and the fictional planet Altair. In 2008 McKinty moved with his family to Melbourne, Australia, to become a full-time writer. He found his greatest success and critical acclaim with the Sean Duffy series, following the eponymous Royal Ulster Constabulary Sergeant during The Troubles, beginning with 2012's The Cold Cold Ground. In 2019, the author made this comment about that novel: "It didn't sell very well, but it ended up getting the best reviews of my career. I got shortlisted for an Edgar, won a couple of awards, and so then that set me on that path for the next six years of reluctantly, kind of being dragged into writing about Northern Ireland in the 1980s". The third Duffy book, In the Morning I'll Be Gone, won the 2014 Ned Kelly Award for Best Novel. McKinty has been an especially astute observer of class in fiction. He also began working as a writer and reviewer for a number of publications including The Guardian, The Sydney Morning Herald, The Washington Post, The Independent, The Australian, The Irish Times and Harpers.
The Republic of Korea Armed Forces issues two types of field rations, Type I and Type II. Type I ration has ready-to-eat foods packed in foil-plastic trilaminate pouches, placed in turn inside a thin cardboard box. Typical contents include: 1 pouch (250 g) precooked white rice with meat and vegetables, plus a separate seasoning packet; 1 pouch (250 g) precooked rice with red beans; 1 packet (100 g) of 6 pork sausages in BBQ; 1 packet (100 g) kimchi; and 1 packet (50 g) cooked black beans. The Type II ration is a smaller, lighter, freeze-dried single-meal ration consisting of several small pouches packed inside a larger gray plastic pouch measuring 225 mm x 200 mm x 90 mm and weighing 278 g. Typical contents include: freeze dried rice (various flavors, usually with meat and vegetables included), a pouch of instant soup, flavored sesame oil, seasoning and spice packets, dried chives and chocolate.
== June 29, 1915 (Tuesday) == Battle of Ngaundere — British colonial forces captured the German-held town of Ngaoundéré, German Cameroon) during the Kamerun campaign. The association football club ABC was established in Natal, Rio Grande do Norte, Brazil and remains the oldest active club in the Brazilian state. The association football Serrano was formed Petrópolis, Rio de Janeiro state, Brazil. Born: Dizzy Trout, American baseball player, pitcher for the Detroit Tigers from 1939 to 1952; as Paul Howard Trout, in Sandcut, Indiana, United States (d. 1972) Died: Jeremiah O'Donovan Rossa, 83, Irish American Fenian leader, advocate for Irish independence through the Fenian Brotherhood and Irish Republican Brotherhood (b. 1831)
Sources: en.wikipedia.org
Diabetes Care. 16 (11): 1470–8. doi:10.2337/diacare.16.11.1470. PMID 8299436. S2CID 23783836. Haakens K., Hanssen K.F.; et al. (1990). "CSII, MDI and conventional insulin therapy in self-selecting insulin-dependent diabetic patients. A comparison of metabolic control acute complications and patient preferences". J Intern Med. 228 (5): 457–464. doi:10.1111/j.1365-2796.1990.tb00263.x. PMID 2254715. S2CID 20197231. Ludvigsson J; et al. (2003). "Continuous Subcutaneous Glucose Monitoring Improved Metabolic Control in Pediatric Patients With Type 1 Diabetes: A Controlled Crossover Study". Pediatrics. 111 (5): 933–8. doi:10.1542/peds.111.5.933. PMID 12728068. S2CID 30709714. Marcus A.O., Fernandez M.P. (1996). "Insulin pump therapy; acceptable alternative to injecting therapy". Postgraduate Medicine. 99: 3. Mudaliar S., Edelman S.V. (2001). "Insulin therapy in type 2 diabetes". Endocrinology and Metabolism Clinics. 39 (4): 935–82. doi:10.1016/s0889-8529(05)70222-x. PMID 11727406. Pitzer KR; et al. (2001). "Detection of Hypoglycemia With the GlucoWatch Biographer". Diabetes Care. 24 (5): 881–885. doi:10.2337/diacare.24.5.881. PMID 11347748. Tsui E.Y.L, Chiasson J.L; et al. (1998). "Counterregulatory hormone responses after long-term CSII with lispro insulin". Diabetes Care. 21 (1): 93–6. doi:10.2337/diacare.21.1.93. PMID 9538976. S2CID 21217439.
Kant thus concluded that even if people did not desire to leave anarchy, they ought to as a matter of duty to abide by universal laws. Kant also gave a short definition of anarchy in contrast to other forms of society:
==== Mechanical interlocking ==== The bioadhesives have the ability to diffuse and penetrate the pores and irregularities in the surface it is adhered to which forms a close interlock. This increases the contact area of the too surfaces and results in an increase in adhesive force. In bioinspired adhesive systems the application of Chitosan, was used as a bridging polymer in a 3D hydrogel network to perform topological wet adhesion. By creating strong physical bonds between synthetic materials, by creating non covalent bonds between H bonds. It was shown that Chitosan causes rapid cohesion 1000 J·m⁻² by 3 and 2000 J·m⁻² by 10 min. Chitosan diffuses and soaks which causes chitosan to move into the polyacrylamide mesh and weave themselves through. Chitosan penetrates deep as ~ 25 μm in tendon and skin after 10 min and 1h of compression respectively.
Sources: en.wikipedia.org
But its first session only materialised in 1869 when, after the 1866 Prussian annexation of the Kingdom of Hanover, the Hanoverian Lutherans desired a representative body separate from Prussian rule, though it was restricted to Lutheran matters only. After the Prussian conquest in 1866, on 19 September 1866, the day before the official Prussian annexation took place and with the last summus episcopus, King George V of Hanover, in exile, the Kingdom's six consistories joined to form today's still-existing church body, the Lutheran State Church of Hanover. An all-Hanoverian consistory, the Landeskonsistorium (state consistory), was formed with representatives from the regional consistories. While the Calvinist congregations in formerly-Prussian East Frisia had a common roof organisation with the Lutherans there ("Coetus") and the Reformed Church in the former County of Bentheim, then being the state church, had fully established church bodies for Bentheim only (German: Königlich-Großbrittanisch-Hannoverscher Ober-Kirchenrath, English: Royal British-Hanoverian Supreme Church Council), the Calvinist congregations elsewhere in Hanover were in a somewhat sorry state. However, some Calvinist congregations of Huguenot origin were organised in the Lower Saxon Confederation (German: Niedersächsische Konföderation). The Lutheran church, being the state church of Hanover, also supervised the Calvinist diaspora parishes outside East Frisia and Bentheim.
Aquacultured shellfish include various oyster, mussel, and clam species. These bivalves are filter and/or deposit feeders, which rely on ambient primary production rather than inputs of fish or other feed. As such, shellfish aquaculture is generally perceived as benign or even beneficial. Depending on the species and local conditions, bivalve molluscs are either grown on the beach, on longlines, or suspended from rafts and harvested by hand or by dredging. In May 2017 a Belgian consortium installed the first of two trial mussel farms on a wind farm in the North Sea. Abalone farming began in the late 1950s and early 1960s in Japan and China. Since the mid-1990s, this industry has become increasingly successful. Overfishing and poaching have reduced wild populations to the extent that farmed abalone now supplies most abalone meat. Sustainably farmed molluscs can be certified by Seafood Watch and other organizations, including the World Wildlife Fund (WWF). WWF initiated the "Aquaculture Dialogues" in 2004 to develop measurable and performance-based standards for responsibly farmed seafood. In 2009, WWF co-founded the Aquaculture Stewardship Council with the Dutch Sustainable Trade Initiative to manage the global standards and certification programs. After trials in 2012, a commercial "sea ranch" was set up in Flinders Bay, Western Australia, to raise abalone. The ranch is based on an artificial reef made up of 5000 (As of April 2016) separate concrete units called abitats (abalone habitats). The 900 kg abitats can host 400 abalone each.
== Political effects == The Napoleonic Wars brought radical changes to Europe, but the reactionary forces returned and restored the Bourbon house to the French throne. Napoleon had succeeded in bringing most of Western Europe under one rule. In most European countries, subjugation in the French Empire brought with it many liberal features of the French Revolution including democracy, due process in courts, abolition of serfdom, reduction of the power of the Catholic Church, and demand for constitutional limits on monarchs. The increasing voice of the middle classes with rising commerce and industry meant that restored European monarchs found it difficult to restore pre-revolutionary absolutism and had to retain many of the reforms enacted during Napoleon's rule. Institutional legacies remain to this day in the form of civil law, with clearly defined codes of law—an enduring legacy of the Napoleonic Code.
Sources: en.wikipedia.org
差别集中在三处：第 8 位残基被非天然氨基酸取代，第 34 位换成精氨酸，第 26 位增加一条脂肪酸侧链。前两处改动降低酶解速率，侧链则通过白蛋白结合延长循环时间。综合结果是半衰期从约两分钟延长到约一周。
胰岛素释放需要细胞内环腺苷酸与钙信号升高，同时依赖葡萄糖代谢产生的协同信号。血糖水平较低时协同信号不足，分泌增强有限。这一机制在降糖效果与低血糖风险之间提供了缓冲。
白蛋白结合是主要原因，它减少肾小球滤过并保护分子免受蛋白酶降解。序列修饰带来的酶解抵抗同样不可忽略，二者共同作用。脂肪链的疏水性还会影响组织分布，但其对总半衰期的贡献程度仍在研究之中。
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.