The short version of lyophilisation fits in a sentence. The long version — which is the one that helps — is below.
This page was last updated on 2026-07-28 and is reviewed periodically as new material appears.
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。
Storage guidance for the finished injectable product distinguishes the unused state from the in-use state. Before first use, pens are kept refrigerated between 2 and 8 degrees Celsius, protected from light, and never frozen, since freezing can disrupt the peptide or the device. After first use, label instructions in several markets permit storage at room temperature up to about 30 degrees Celsius for a limited number of days. Solid research-grade material is normally held at or below minus 20 degrees Celsius, often with desiccant, and allowed to equilibrate before opening.
Quantification and purity assessment rely on separation methods coupled to optical or mass detection. Reversed-phase high-performance liquid chromatography resolves the intact peptide from related impurities and is the standard assay technique. Size-exclusion chromatography measures aggregates, while ion-exchange chromatography separates charge variants produced by deamidation. Mass spectrometry confirms identity and detects mass shifts of a few daltons. In biological matrices, liquid chromatography with tandem mass spectrometry is often used because immunoassays can cross-react with endogenous GLP-1 or with circulating fragments.
| 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.
Degradation proceeds along several parallel routes. Deamidation of asparagine and glutamine residues generates charged variants that shift retention time in chromatographic analysis. Oxidation targets methionine and can be accelerated by trace metals or dissolved oxygen. Non-covalent aggregation produces dimers, oligomers, and larger species that are difficult to reverse. Isomerisation at aspartate residues is slower but measurable under thermal stress. The distribution among these pathways depends on pH, buffer composition, ionic strength, and the presence of excipients such as sugars or surfactants.
Reverse-phase high-performance liquid chromatography with ultraviolet detection near 214 nm is the standard purity method, reported as area percent. Mass spectrometry, usually with electrospray ionisation, confirms identity and reveals covalent modifications. Size-exclusion chromatography quantifies aggregates and fragments. Peptide mapping after enzymatic digestion localises changes to specific sequence regions. Circular dichroism and infrared spectroscopy report on secondary structure, while light scattering tracks particle formation in liquid formulations. No single technique captures every quality attribute.
Quality control relies on pharmacopoeial monographs where they exist, combined with in-house specifications for identity, purity, water content, and counter-ion composition. Reference standards allow calibration across laboratories, although certified materials for every analogue are not universally obtainable. Batch records, chromatograms, and mass spectra form the documentation trail. Regulatory classification varies by jurisdiction and intended use, and research-grade material differs from pharmaceutical-grade material in testing scope. Analytical uncertainty is often expressed as relative standard deviation across replicate injections.
In 1937, Szent-Györgyi was awarded the Nobel Prize in Physiology or Medicine for his discovery. In 1943, Edward Adelbert Doisy and Henrik Dam were awarded the Nobel Prize in Physiology or Medicine for their discovery of vitamin K and its chemical structure. In 1938, Richard Kuhn was awarded the Nobel Prize in Chemistry for his work on carotenoids and vitamins, specifically B2 and B6. Five people have been awarded Nobel Prizes for direct and indirect studies of vitamin B12: George Whipple, George Minot and William P. Murphy (1934), Alexander R. Todd (1957), and Dorothy Hodgkin (1964). In 1967, George Wald, Ragnar Granit and Haldan Keffer Hartline were awarded the Nobel Prize in Physiology and Medicine "...for their discoveries concerning the primary physiological and chemical visual processes in the eye." Wald's contribution was discovering the role vitamin A had in the process.
At Survivor Series on November 19, Triple H aimed to run Austin down again during their match but his plot failed when Austin lifted Triple H's car with a forklift, then let it drop 20 feet. Austin won his third Royal Rumble match on January 21, 2001, last eliminating Kane. His rivalry against Triple H ended at No Way Out on February 25 in a Three Stages of Hell match, with Triple H defeating Austin two falls to one. With The Rock defeating Angle for the WWF Championship at No Way Out, Austin was again set to face him at WrestleMania X-Seven on April 1. In the weeks leading up to WrestleMania, animosity grew between Austin and The Rock, stemming from Austin's wife, Debra, being assigned to be The Rock's manager by McMahon. The match at WrestleMania was made a no disqualification match. During the match, McMahon came to the ring, preventing The Rock from pinning Austin on two separate occasions and giving Austin a steel chair. Austin then hit The Rock several times with the chair before pinning him to win the WWF Championship for the fifth time. After the match, Austin shook hands with McMahon, turning heel for the first time since 1997. During a steel cage match with The Rock in a rematch for the WWF Championship the following night on Raw is War, Triple H came down to the ring with a sledgehammer. After teasing siding with The Rock, Triple H instead aligned himself with Austin and McMahon, attacking The Rock and put him out of action.
social: criminal groups seek to develop social control in relation to particular communities; economic: seek to exert influence by means of corruption and by coercion of legitimate and illegitimate praxis; and, political: criminal groups use corruption and violence to attain power and status. Contemporary organized crime may be very different from traditional Mafia style, particularly in terms of the distribution and centralization of power, authority structures and the concept of 'control' over one's territory and organization. There is a tendency away from centralization of power and reliance upon family ties towards a fragmentation of structures and informality of relationships in crime groups. Organized crime most typically flourishes when a central government and civil society is disorganized, weak, absent or untrustworthy. This may occur in a society facing periods of political, economic or social turmoil or transition, such as a change of government or a period of rapid economic development, particularly if the society lacks strong and established institutions and the rule of law. The dissolution of the Soviet Union and the Revolutions of 1989 in Eastern Europe that saw the downfall of the Communist Bloc created a breeding ground for criminal organizations. The newest growth sectors for organized crime are identity theft and online extortion. These activities are troubling because they discourage consumers from using the Internet for e-commerce.
=== United States herbalism fraud === Over the years 2017–2021, the US Food and Drug Administration (FDA) issued warning letters to numerous herbalism companies for illegally marketing products under "conditions that cause them to be drugs under section 201(g)(1) of the Act [21 U.S.C. § 321(g)(1)], because they are intended for use in the diagnosis, cure, mitigation, treatment, or prevention of disease and/or intended to affect the structure or any function of the body" when no such evidence existed. During the COVID-19 pandemic, the FDA and US Federal Trade Commission issued warnings to several hundred American companies for promoting false claims that herbal products could prevent or treat COVID-19 disease.
Sources: en.wikipedia.org
where lw is the activity coefficient of water and xw is the mole fraction of water in the aqueous fraction. Relationship to relative humidity: The relative humidity (RH) of air in equilibrium with a sample is also called the Equilibrium Relative Humidity (ERH) and is usually given as a percentage. It is equal to water activity according to
An insulin port functions as a medication delivery channel directly into the subcutaneous tissue (the tissue layer located just beneath the skin). When applying the injection port, an insertion needle guides a soft cannula (a small, flexible tube) under the skin. Once applied, the insertion needle is removed and only the soft cannula remains below the skin, acting as the gateway into the subcutaneous tissue. To inject through an insulin port the needle of a syringe or insulin pen is used. It is usually used to deliver insulin through the use of an insulin pump. The needle remains above the surface of the skin, while the medication is immediately delivered through the soft cannula and into the subcutaneous tissue.
The hypothalamic–pituitary–somatotropic axis (HPS axis), or hypothalamic–pituitary–somatic axis, also known as the hypothalamic–pituitary–growth axis, is a hypothalamic–pituitary axis which includes the secretion of growth hormone (GH; somatotropin) from the somatotropes of the pituitary gland into the circulation and the subsequent stimulation of insulin-like growth factor 1 (IGF-1; somatomedin-1) production by GH in tissues such as, namely, the liver. Other hypothalamic–pituitary hormones such as growth hormone-releasing hormone (GHRH; somatocrinin), growth hormone-inhibiting hormone (GHIH; somatostatin), and ghrelin (GHS) are involved in the control of GH secretion from the pituitary gland. The HPS axis is involved in postnatal human growth. Individuals with growth hormone deficiency or Laron syndrome (GHRTooltip growth hormone receptor insensitivity) show symptoms like short stature, dwarfism and obesity, but are also protected from some forms of cancer. Conversely, acromegaly and gigantism are conditions of GH and IGF-1 excess usually due to a pituitary tumor, and are characterized by overgrowth and tall stature.
Sources: en.wikipedia.org
Exercise programs, either at home or supervised Low intensity aerobic exercise, e.g. Pilates Spa-exercise therapy Aquatic physical therapy Proprioceptive neuromuscular facilitation (PNF) Heat therapy Cryotherapy in conjunction with exercise
Removal of the Wall began on the evening of 9 November 1989 and continued over the following days and weeks, with people nicknamed Mauerspechte (wallpeckers) using various tools to chip off souvenirs, demolishing lengthy parts in the process, and creating several unofficial border crossings. In the season holidays this became a sort of international action. People from all over the western world went to West Berlin and local youth provided a range of appropriate demolition tools. Television coverage of citizens demolishing sections of the Wall on 9 November was soon followed by the East German regime announcing ten new border crossings, including the historically significant locations of Potsdamer Platz, Glienicker Brücke, and Bernauer Straße. Crowds gathered on both sides of the historic crossings waiting for hours to cheer the bulldozers that tore down portions of the Wall to reconnect the divided roads. While the Wall officially remained guarded at a decreasing intensity, new border crossings continued for some time. Initially the East German Border Troops attempted repairing the damage done by the "wallpeckers"; gradually these attempts ceased, and guards became laxer, tolerating the increasing demolitions and "unauthorized" border crossing through the holes.
== Enzymology == 5-HEDH is an NADPH dehydrogenase oxidoreductase enzyme. It transfers a hydrogen cation (or hydron) H+ from 5(S)-hydroxy (i.e. 5(S)-OH) residues of its fatty acid targets to nicotinamide adenine dinucleotide phosphate+ (NADP+) to form 5-oxo (i.e. 5-O=) counterparts of its targets plus reduced NADP+, i.e. NADPH. The reaction (where R indicates a long chain [14 or more carbons] fatty acid) is:
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。
Ice formation concentrates solutes and can mechanically stress the peptide or damage the delivery device. Thawing afterwards may leave aggregates that are not visible to the eye. Refrigeration keeps the solution above its freezing point while slowing chemical degradation.