The short version of 冻干粉 fits in a sentence. The long version — which is the one that helps — is below.
Reviewed 2025-10-25. Anything still debated is marked as such rather than presented as settled.
Long-term storage of the solid generally relies on temperatures at or below minus twenty degrees Celsius, while short-term working stocks may be held refrigerated. Light exposure is limited because photodegradation can alter side chains over extended periods. Solutions prepared for analysis are less stable than the dry powder and are typically used within the same working day. Buffer choice matters, since some aqueous conditions favor deamidation or oxidation at specific residues. Stability data are usually generated under defined accelerated conditions and then extrapolated with stated assumptions.
Identity and purity are established with reversed-phase high-performance liquid chromatography, often paired with mass spectrometry for confirmation of the expected mass. Peptide mapping after enzymatic digestion verifies the primary sequence and detects substitutions. Size-exclusion chromatography quantifies aggregates and fragments, which are the impurities most often tracked for peptides of this size. Residual solvents, counterions, and water content fall under separate tests described in pharmacopeial chapters. Circular dichroism or nuclear magnetic resonance may be used in research settings to probe secondary structure, though such methods are less common in routine release testing.
Structural work on the molecule centers on a C20 fatty diacid moiety attached through a linker to the peptide backbone. This side chain promotes reversible binding to serum albumin, which slows renal clearance and supports a prolonged action profile. The peptide backbone incorporates aminoisobutyric acid substitutions that limit recognition by digestive enzymes. Together these modifications produce a molecule that is stable enough for subcutaneous delivery but still dependent on careful manufacturing control. Analytical characterization of the active pharmaceutical ingredient typically follows the conventions used for other synthetic peptides.
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.
| Property | Value | Notes |
|---|---|---|
| Typical supplied form | Lyophilized powder | Hygroscopic, seal promptly after opening |
| Long-term storage temperature | At or below minus 20 C | Protect from repeated freeze-thaw |
| Working solution stability | Hours when refrigerated | Use within the same working day |
| Primary purity method | Reversed-phase HPLC | Often paired with mass spectrometry |
| Aggregate measurement | Size-exclusion chromatography | Reports high-molecular-weight species |
固体状态的 tirzepatide 通常以冻干粉形式保存，推荐在低温、避光、干燥条件下存放，常见区间为 2 至 8 摄氏度，长期保存可考虑更低温度并避免反复冻融。冻融循环会导致肽链聚集或析出，从而影响后续定量结果。容器密封性与湿度控制同样是稳定性研究中反复强调的因素。
溶解操作一般使用注射用水或适宜的水性缓冲液，必要时加入少量助溶剂以改善溶解速度，但应避免剧烈涡旋振荡，因为剪切力可能促进聚集。配制后的溶液在冷藏条件下的稳定时间通常短于固体形态，具体时限取决于浓度、缓冲体系与容器材质。是否加入防腐成分，则取决于用途是否为多次取样。
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。
在生理层面，GIP 与 GLP-1 均为肠道内分泌细胞分泌的肠促胰素，进食后参与胰岛素分泌调节与胃排空抑制。Tirzepatide 通过同时激活这两条信号通路，使胰岛素分泌的葡萄糖依赖性增强，并延缓冲胃排空、降低食欲信号。与单一 GLP-1 激动相比，双靶点作用在血糖控制和体重变化上的效应幅度更大，但具体贡献比例仍在研究之中。
脂肪酸侧链的存在使该肽与血浆白蛋白结合能力增强，从而延长循环半衰期，支持每周一次给药的用药间隔。白蛋白结合同时改变组织分布特征，减慢肾脏清除速度。该设计思路在多种长效肽类药物中被反复采用，属于既定的药代动力学策略。
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.
Stability depends strongly on physical form. The dry powder is generally regarded as stable for extended periods when held at or below minus twenty degrees Celsius in a sealed, desiccated container. In solution, degradation pathways include deamidation of asparagine and glutamine residues, oxidation of methionine, and aggregation. Reaction rates for these pathways rise with temperature. Repeated freezing and thawing of solutions promotes aggregation, and light exposure can accelerate some oxidative changes. Buffer composition and pH influence which pathway dominates at a given temperature.
==== Transplastomic plants ==== Recently, chloroplasts have caught attention by developers of genetically modified crops. Since, in most flowering plants, chloroplasts are not inherited from the male parent, transgenes in these plastids cannot be disseminated by pollen. This makes plastid transformation a valuable tool for the creation and cultivation of genetically modified plants that are biologically contained, thus posing significantly lower environmental risks. This biological containment strategy is therefore suitable for establishing the coexistence of conventional and organic agriculture. While the reliability of this mechanism has not yet been studied for all relevant crop species, recent results in tobacco plants are promising, showing a failed containment rate of transplastomic plants at 3 in 1,000,000.
With the army unmobilised and the headquarters thus unprotected, on 22 December protesters stormed the building and Victor Stănculescu convinced the Romanian leader to flee with his wife via helicopter. Denounced afterward by Stănculescu, they suddenly found themselves as fugitives and thus seemingly guilty of accused crimes, and a manhunt was declared. Captured in Târgoviște, they were tried by a drumhead military tribunal on charges of genocide, damage to the national economy, and abuse of power to execute military actions against the Romanian people. They were convicted on all charges, sentenced to death, and immediately executed on Christmas Day 1989. They were the last people to be condemned to death and executed in Romania, as capital punishment was abolished soon after. For several days after Ceaușescu fled, many would be killed in the crossfire between civilians and armed forces personnel which believed the other to be Securitate 'terrorists'. Although news reports at the time and modern media often makes reference to the Securitate fighting against the revolution, there has never been any evidence supporting the claim of an organised effort. Hospitals in Bucharest were treating as many as thousands of civilians. Following an ultimatum, many Securitate members turned themselves in on 29 December with the assurance they would not be tried. Present-day Romania has unfolded in the shadow of the Ceaușescus along with its Communist past, and its tumultuous departure from it.
Balancing and buck passing are the main strategies for preserving the balance of power and preventing a potential hegemon's rise. Instead of balancing against an aggressor, some states instead choose to "pass the buck" whereby instead of taking action to prevent a potential rise, it will pass the responsibility on to another state. John Mearsheimer, a prominent offensive realist, claims that threatened states can take four measures to facilitate buck passing, including: seeking good diplomatic relations with the aggressor in the hope that it will divert its attention to the "buck-catcher"; maintaining cool relations with the buck-catcher so as not to get dragged into the war with the buck-catcher and as a result possibly increase positive relations with the aggressor; increasing military strength to deter the aggressive state and help it focus on the buck-catcher; and facilitating the growth in power of the intended buck-catcher. In the case that a state is an enemy with both the aggressor and the intended buck-catcher, a buck-passer can implement a bait and bleed strategy whereby the state causes two rivals to engage in a protracted war while the baiter remains on the sideline. This form of buck passing enables the state to increase in relative strength at the expense of the two rivals. Bloodletting, a further variant whereby a state does what it can to increase the cost duration of the conflict can further increase the buck-passer's relative power.
The 2011 census stated that a majority of the population were Christians (71.93%); 51.48% of the total population were members of the Protestant Church in Germany, 18.34% were Catholics, 2.11% were members of other Christian denominations, 2.27% were members of other religions. 25.8% have no denomination. Even though there is a high level of official belonging to a Christian denomination, the people – especially in the cities – are highly secular in behaviour. As of 2020, the Protestant Church in Germany was the faith of 41.1% of the population. It is organised in the five Landeskirchen named Evangelical Lutheran State Church in Brunswick (comprising the former Free State of Brunswick), Evangelical Lutheran Church of Hanover (comprising the former Province of Hanover), Evangelical Lutheran Church in Oldenburg (comprising the former Free State of Oldenburg), Evangelical Lutheran Church of Schaumburg-Lippe (comprising the former Free State of Schaumburg-Lippe), and Evangelical Reformed Church (covering all the state). Together, these member churches of the Protestant Church in Germany gather a substantial part of the Protestant population in Germany. The Catholic Church was the faith of 16.3% of the population in 2020. It is organised in the three dioceses of Osnabrück (western part of the state), Münster (comprising the former Free State of Oldenburg) and Hildesheim (northern and eastern part of the state). The Catholic faith is mainly concentrated to the regions of Oldenburger Münsterland, the region of Osnabrück, the region of Hildesheim and in the Western Eichsfeld.
== The Human Growth Hormone, Creutzfeld Jakob Disease Controversy == Wilhelmi was an important researcher involved in harnessing human grown hormone from cadavers in the 1960s and 1970s. Early studies conducted in 1958 by Maurice Raben at Tufts University School of Medicine showed it was possible to cause children with pituitary dwarfism to grow by injecting them with human growth hormone. In 1961, the National Institutes of Health (NIH) formed the National Pituitary Agency to organize collection and redistribution of human endocrine glands to three universities for processing into growth hormone: Emory University, Tufts University and Cornell University. For the first 14 of these years, Wilhelmi supervised the Emory laboratory, which was the largest seat of hormone production. In 1985, however, two patients who previously had received the exogenous hormone treatment died in the United States. That caused the NIH to suspend the human growth hormone program and launch an investigation. The deaths were attributed to Creutzfeldt–Jakob disease (CJD) transmitted by impurities in the hormone injected into the patients years earlier using the Wilhelmi protocol. As of 2000, there had been 22 CJD deaths among American recipients of unfiltered hormone prior to 1977.
Sources: en.wikipedia.org
Can resolve fine-scale variations in chemical elements. Can be used to identify the presence and distribution of different phases in materials. Requires less sample material and therefore can provide information on microscopic objects. Handling of small quantities is not always simple. Higher accuracy of weighing is necessary (e.g. use of accurate balance). Sample surface preparation can have a major impact on measurement results.
Tuberculin, known in its modern form as purified protein derivative (PPD), is a combination of proteins that are used in the diagnosis of tuberculosis by injection into the skin. Common side effects include redness, itchiness (pruritus), and pain at the site of injection. Allergic reactions may occasionally occur. Use is safe in pregnancy. The original tuberculin, a glycerin extract of Mycobacterium tuberculosis, was discovered in 1890 by Robert Koch. Koch, best known for his work on the etiology (cause, origin) of tuberculosis (TB), laid down various rigorous guidelines that aided the establishment between a pathogen and the specific disease that followed that were later named Koch's postulates. Although he initially believed it would cure tuberculosis, this was later disproved. PPD was invented in 1934 by Florence B. Seibert, greatly improving the reliability of the skin test over Koch's extract. PPD is on the World Health Organization's List of Essential Medicines.
He made one of his final TV appearances during season 5 on Oprah: Where Are They Now? He voiced characters in the television series Captain Planet and the Planeteers, Fish Police, and Happily Ever After: Fairy Tales for Every Child. He was known for the voice of Rafiki in the movie The Lion King and its sequels and spin-offs. He lent his deep tenor voice as Mr. Thicknose in The Land Before Time VIII: The Big Freeze. He also supplied the voice for Eli Vance in the 2004 video game Half-Life 2 and its episodic sequels.
16 October An overview of detecting life on Earth from distant star-based systems is published. Scientists propose a new law of evolution, extending the established Darwinian ones, and described as the "law of increasing functional information". 21 species in the United States are declared extinct by the US Fish and Wildlife Service. These are one mammal, ten birds, two fish, and eight mussels. Scientists report the facial reconstruction of Pierolapithecus catalaunicus, a 12 million years old great ape. 19 October Astronomers report that FRB 20220610A, a Fast Radio Burst, took 8 billion years to reach Earth. Astronomers report the finding, for the first time, of Ultra-Fast Radio Bursts lasting millionths of a second. A new edge-based computer processor called NorthPole is developed by IBM Research, able to run AI-based image recognition apps 22 times faster than chips currently on the market. A study links a large marine macrofauna population collapse mortality event, the death of ~10 billion snow crabs around 2018, to marine heatwaves that caused mass starvation. 20 October – A study reports evidence of recent plant adaptive evolution, involving a leaf color change from green to red of a woodsorrel, due to urban heat islands. It provides information regarding evolutionary dynamics of climate change and human adaptation. 23 October – A significant breakthrough in treating cervical cancer is reported, with participants in a Phase III trial seeing a 35% reduction in the risk of both mortality or the disease returning.
=== Homocysteine === Homocysteine, a non-protein amino acid and analogue to the protein amino acid cystine, has been shown to have negative effects on bone health. Higher homocysteine concentrations are likely a result of folate, vitamin B12 B6 deficiencies. In addition, it was found that homocysteine concentration was significantly affected by physical activity. The stimulation of the skeleton through physical activity promotes positive bone remodelling and decreases levels of homocysteine, independently from nutritional intake. Four methods have been proposed regarding the interaction of homocysteine and bone; increase in osteoclast activity, decrease in osteoblast activity, decrease in bone blood flow, and direct action of homocysteine on bone matrix. Homocysteine inhibits lysyl oxidase which is responsible for post-translational modifications of collagen, a key component to bone structure
Sources: en.wikipedia.org
In Australia, ketamine is listed as a Schedule 8 controlled drug under the Poisons Standard (October 2015). In Canada, ketamine has been classified as a Schedule I narcotic since 2005. In December 2013, the government of India, in response to rising recreational use and the use of ketamine as a date rape drug, added it to Schedule X of the Drug and Cosmetics Act, requiring a special license for sale and maintenance of records of all sales for two years. In the United Kingdom, it was labeled a Class B drug on 12 February 2014. In 2025, the Home Office requested a review of the classification with a view to changing it to Class A, based on an increase in recreational use and the negative health consequences. The increase in recreational use prompted ketamine to be placed in Schedule III of the United States Controlled Substances Act in August 1999.
=== Canada === In March 2002, Whirlpool announced it would close its last manufacturing facility in Canada, the Inglis plant in Montmagny, Quebec, by 2004, terminating 500 workers and shifting production to facilities in Tulsa, Oklahoma and Oxford Mississippi.
== Sources == Katz, Arie; Nambi, Sridhar S.; Mather, Kieren; Baron, Alain D.; Follmann, Dean A.; Sullivan, Gail; Quon, Michael J. (2000-07-01). "Quantitative Insulin Sensitivity Check Index: A Simple, Accurate Method for Assessing Insulin Sensitivity In Humans". The Journal of Clinical Endocrinology & Metabolism. 85 (7): 2402–2410. doi:10.1210/jcem.85.7.6661. ISSN 0021-972X. PMID 10902785. Source as above - Katz et al. Also data for unusually healthy individuals derived from those practicing caloric restriction. See CR Society for details.
==== G6PDH inhibitor ==== DHEA is an uncompetitive inhibitor of G6PDHTooltip glucose-6-phosphate dehydrogenase (Ki = 17 μM; IC50 = 18.7 μM), and is able to lower NADPHTooltip nicotinamide adenine dinucleotide phosphate levels and reduce NADPH-dependent free radical production. It is thought that this action may possibly be responsible for much of the antiinflammatory, antihyperplastic, chemopreventative, antihyperlipidemic, antidiabetic, and antiobesic, as well as certain immunomodulating activities of DHEA (with some experimental evidence to support this notion available). However, it has also been said that inhibition of G6PDH activity by DHEA in vivo has not been observed and that the concentrations required for DHEA to inhibit G6PDH in vitro are very high, thus making the possible contribution of G6PDH inhibition to the effects of DHEA uncertain.
Sources: en.wikipedia.org
Water promotes hydrolysis and deamidation, so removing it slows degradation during transport and storage. The dry solid is also less prone to microbial growth than a solution. Reconstitution is therefore performed close to the point of use.
Reversed-phase high-performance liquid chromatography is the standard method for purity and related substances. It separates the main peak from deletion sequences and oxidation products. Mass spectrometry is frequently used alongside it to confirm molecular identity.
Aggregates, truncated sequences, and oxidation products receive the most attention. Size-exclusion chromatography covers aggregates, while reversed-phase methods resolve many chemical variants. Limits are set according to the route of administration and the expected exposure.
It activates both the glucose-dependent insulinotropic polypeptide receptor and the glucagon-like peptide-1 receptor. This dual activity separates it from agents that act on only one of the two receptors. The relative contribution of each receptor to clinical effects remains an open area of study.