This is a working overview of 反相色谱, written for readers who want more than a one-paragraph summary but less than a textbook.
Reviewed 2026-06-27. Anything still debated is marked as such rather than presented as settled.
稳定性研究一般关注脱酰胺、氧化与聚集三类降解路径。脱酰胺多发生在天冬酰胺残基上，氧化常涉及甲硫氨酸与色氨酸，聚集则与浓度、温度以及容器界面接触有关。强制降解实验用于识别分子中较敏感的位点。这些结果会直接影响储存条件的设定与有效期的判断。
冻干粉通常在低温环境下保存，复溶之后需要按指定条件在较短时间内使用。反复冻融和剧烈振荡可能促进聚集，低吸附容器则能减少多肽在管壁上的损失。批号、日期与处理条件的完整记录，是后续复核与问题追溯的基础。
供应环节涉及来源核实与文件审核两类工作。分析证书、批次记录以及第三方检测报告构成常见的可追溯材料。来源不清的样品很难确认身份与纯度，因此核实步骤在实际操作中具有明确意义。缺少方法细节的报告通常无法复核。
Identification and purity assessment typically rely on reversed-phase high-performance liquid chromatography, often paired with mass spectrometry. Mass measurement confirms the expected molecular mass and can reveal truncations or modifications. Peptide mapping and sequencing techniques provide sequence-level confirmation when needed. Because related peptide impurities can behave similarly in a single method, orthogonal techniques are usually combined. Reported purity values depend heavily on the method used and should be interpreted with that in mind.
Dissolution behavior depends on the amino acid sequence, the counterion content, and the buffer chosen. Many peptides disperse readily in water or mild aqueous buffers, while others require a small amount of organic co-solvent or a change in pH. Adsorption to plastic and glass surfaces can reduce the concentration of a solution over time, particularly at low concentrations. Filtration before analysis removes particulates, and aliquoting limits repeated freeze-thaw cycles that stress the material.
| Property | Value | Notes |
|---|---|---|
| 长期储存温度 | 约 -20°C 或更低 | 冻干粉常见保存条件 |
| 复溶溶剂 | 注射用水或指定缓冲液 | 按方案或说明书执行 |
| 容器材质 | 低吸附聚丙烯 | 减少多肽在管壁的吸附损失 |
| 主要降解路径 | 脱酰胺、氧化、聚集 | 由序列与工艺条件共同决定 |
| 追溯材料 | 分析证书与批次记录 | 用于来源与纯度核实 |
Clinical development has progressed through phase 2 trials in adults with obesity and type 2 diabetes, with phase 3 programs reported as ongoing. Reported outcomes include reductions in body weight and improvements in glycemic measures over defined treatment periods. Whether these effects translate into durable benefits after treatment ends remains an open question. Long-term safety data across broad populations are not yet complete, and regulatory decisions have not been announced.
Retatrutide is an investigational synthetic peptide engineered to activate three distinct hormone receptors within a single molecule. It targets the glucose-dependent insulinotropic polypeptide receptor, the glucagon-like peptide-1 receptor, and the glucagon receptor simultaneously. This triagonist design distinguishes it from earlier incretin-based compounds that act on one or two of these pathways. Structural modifications relative to native gut hormones extend its residence time in circulation. The molecule remains under clinical evaluation and is not approved for any indication.
Receptor activation produces downstream effects that differ by tissue. GLP-1 receptor signaling influences appetite regulation and insulin secretion in a glucose-dependent manner. GIP receptor activity contributes to metabolic handling of nutrients and may modulate adipose tissue. Glucagon receptor engagement raises energy expenditure and promotes hepatic lipid turnover, though the balance among these actions in humans is still being characterized. Preclinical models showed reductions in body weight and improved glycemic markers.
Quantification of the peptide in biological samples generally relies on liquid chromatography coupled with tandem mass spectrometry. This approach separates the analyte from matrix components and detects it by mass-to-charge transitions specific to the molecule. Immunoassays offer higher throughput but can cross-react with related peptides and metabolites, so mass spectrometric methods are preferred when structural confirmation is required. Method validation typically addresses accuracy, precision, selectivity, and stability under handling conditions.
Several questions remain unresolved. It is not yet known whether the compound reduces cardiovascular events or mortality, because outcome studies require long follow-up. The durability of weight reduction after treatment withdrawal is uncertain, and rebound has been observed with other incretin-based therapies. Long-term safety data covering several years are limited. Effects in adolescents, in pregnancy, and in people with significant kidney or liver impairment have not been characterized in published reports.
Clinical studies have reported notable reductions in body weight among participants. Early trials measured safety and explored several dose levels, and later studies tracked body-weight change over months of treatment. Investigators also monitor effects on glycemic markers, liver fat, and blood lipids. Because the compound is still in development, questions about long-term safety, cardiovascular outcomes, and durability after treatment ends remain open.
The three-receptor design places retatrutide in a distinct category relative to older incretin-based therapies. Single agonists target one receptor, and dual agonists target two. Adding a third target broadens the pharmacological footprint and introduces new trade-offs among efficacy, tolerability, and glucose control. How these trade-offs resolve in large trials is a central focus of current research.
Prior to 1919 only atomic weights averaged over a very large number of atoms was available. In that year, Francis Aston built the first mass spectrograph, an improved form of a device built by J. J. Thomson to measure the deflection of positively charged atoms by electric and magnetic fields. Aston was then able to separate the isotopes of many light elements including neon, 20Ne and 22Ne. Aston discovered the isotopes matched William Prout's whole number rule: the mass of every isotope is a whole number multiple of hydrogen. Significantly, the one exception to this whole number rule was hydrogen itself, which had a mass value of 1.008. The excess mass was small, but well outside the limits of experimental uncertainty. Aston and others realized this difference was due to the binding energy of atoms. When a number of hydrogen atoms are bound into an atom, that atom's energy must be less than the sum of the energies of the separate hydrogen atoms. That lost energy, according to the mass-energy equivalence principle, means the atomic mass will be slightly less than the sum of the masses of its components. Aston's work on isotopes won him the 1922 Nobel Prize in Chemistry for the discovery of isotopes in a large number of non-radioactive elements, and for his enunciation of the whole number rule.
=== Immune dysfunction === Arsenic exposure in small children distorts the ratio of T helper cells (CD4) to cytotoxic T cells (CD8), which are responsible for immunodepression. In addition, arsenic also increases the number of inflammatory molecules being secreted through macrophages. The excess amount of granulocytes and monocytes lead to a chronic state of inflammation, which might result in cancer development.
Algae that form aggregations that have been described as turfs include diatoms, cyanobacteria, chlorophytes, phaeophytes and rhodophytes. Turfs are often composed of numerous species at a wide range of spatial scales, but monospecific turfs are frequently reported. Turfs can be morphologically highly variable over geographic scales and even within species on local scales and can be difficult to identify in terms of the constituent species. Turfs have been defined as short algae, but this has been used to describe height ranges from less than 0.5 cm to more than 10 cm. In some regions, the descriptions approached heights which might be described as canopies (20 to 30 cm).
It is likely bloodletting was an antecedent to acupuncture. According to historians Lu Gwei-djen and Joseph Needham, there is substantial evidence that acupuncture may have begun around 600 BC. Some hieroglyphs and pictographs from that era suggests acupuncture and moxibustion were practised. However, historians Lu and Needham said it was unlikely a needle could be made out of the materials available in China during this time period. It is possible that bronze was used for early acupuncture needles. Tin, copper, gold and silver are also possibilities, though they are considered less likely, or to have been used in fewer cases. If acupuncture was practised during the Shang dynasty (1766 to 1122 BC), organic materials like thorns, sharpened bones, or bamboo may have been used. Once methods for producing steel were discovered, it would replace all other materials, since it could be used to create a very fine, but sturdy needle. Lu and Needham noted that all the ancient materials that could have been used for acupuncture and which often produce archaeological evidence, such as sharpened bones, bamboo or stones, were also used for other purposes. An article in Rheumatology said that the absence of any mention of acupuncture in documents found in the tomb of Mawangdui from 198 BC suggest that acupuncture was not practised by that time.
Sources: en.wikipedia.org
=== Post‑marketing surveillance and safety signals === Following the launch of the once‑monthly paliperidone palmitate formulation (Xeplion) in Japan on 19 November 2013, the Early Post‑Marketing Phase Vigilance (EPPV) system detected a signal of increased mortality: 32 deaths were reported among an estimated 11,000 patients during the six‑month EPPV period. The most common causes of death were sudden cardiac death (12 confirmed and 4 suspected cases), suicide (7 cases), and neuroleptic malignant syndrome (4 cases). Of the 32 deaths, 59.4% were in patients over 50 years of age, 71.9% had cardiovascular risk factors, and 78.1% were receiving antipsychotic polypharmacy. Earlier in the EPPV period, in April 2014, it had been reported that 21 Japanese people who had received shots of the long-acting injectable paliperidone palmitate had died, out of 10,700 individuals prescribed the drug. An observational study of the French pharmacovigilance database identified 13 deaths and 14 life‑threatening events among 473 paliperidone palmitate-related adverse drug reaction reports between 1 January 2013 and 31 December 2019. The reactions were primarily cardiorespiratory, with cardiac arrests and sudden unexpected deaths often occurring 10–14 days after a once‑monthly injection (or 11–24 days after a three‑monthly injection), consistent with peak plasma drug levels, leading the authors to hypothesize that supratherapeutic drug levels may underlie these events. A 2025 real‑world pharmacovigilance study using the U.S.
== History == The first generation of MMP inhibitors were based on the structure of the collagen molecule. This group of inhibitors contain a hydroxamate (-CONHOH) group that binds the zinc atom in the active site of the MMP enzyme. The first MMP inhibitors that were tested in patients were Ilomastat and Batimastat, hydroxamate-based MMP inhibitors. However, neither compound showed good oral bioavailability. Thus far, Periostat (active ingredient is doxycycline hyclate) is the only MMP inhibitor that has been approved by the U.S. Food and Drug Administration (FDA). It is used for the treatment of periodontitis. Other MMP inhibitors have exhibited serious side effects during preclinical trials. These side effects are caused by insufficient selectivity. Most MMP inhibitors are unable to target specific MMPs connected to specific pathological conditions. Instead, they inhibit multiple MMPs, some of which have protective functions or are not related to pathology. MMPs have been regarded as promising targets for cancer therapy. Preclinical studies investigating the efficacy of MMP suppression in tumor models were encouraging. Following these results, clinical studies were conducted but turned out to be disappointing. Recent studies have shown that MMPs may even have paradoxical roles in tumor progression. MMPs seem to have tumor-promoting effects as well as tumor suppressive effects dependent on different contexts.
== Uses == Thorium has been suggested for use in thorium-based nuclear power. In many countries the use of thorium in consumer products is banned or discouraged because it is radioactive. It is currently used in cathodes of vacuum tubes, for a combination of physical stability at high temperature and a low work energy required to remove an electron from its surface. It has, for about a century, been used in mantles of gas and vapor lamps such as gas lights and camping lanterns.
=== Other mechanisms === Bimagrumab, an experimental drug, works by inhibiting the action of myostatin, which limits the size of skeletal muscle. The drug has shown the ability to increase lean mass simultaneously to decreasing fat mass in obese humans, which is beneficial because it preserves or increases energy expenditure while reducing risks associated with excess fat. Orlistat (Xenical) and cetilistat are lipase inhibitors that reduce intestinal fat absorption by inhibiting pancreatic lipase, an enzyme that breaks down triglycerides in the intestine. Without this enzyme, triglycerides from the diet are prevented from being hydrolyzed into absorbable free fatty acids and are excreted undigested. Frequent oily bowel movements steatorrhea is a possible side effect of using orlistat. Originally available only by prescription, it was approved by the FDA for over-the-counter sale in February 2007. SGLT2 inhibitors cause the loss of 60–100 grams (2.1–3.5 oz) glucose in the urine each day and are associated with a modest, sustained weight loss of 1.5–2 kilograms (3.3–4.4 lb) in people with type 2 diabetes. The weight loss is less than expected due to compensatory increases in energy intake, but is additive when combined with GLP-1 receptor agonists.
In winemaking, the term "wild yeast" has multiple meanings. In its most basic context, it refers to yeast that has not been introduced to the must by intentional inoculation of a cultured strain. Instead, these "wild yeasts" often come into contact with the must through their presence on harvest equipment, transport bins, the surface winemaking equipment and as part of the natural flora of a winery. Very often these are strains of Saccharomyces cerevisiae that have taken residence in these places over the years, sometimes being previously introduced by inoculation of prior vintages. In this context, these wild yeasts are often referred to as ambient, indigenous or natural yeast as opposed to inoculated, selected or cultured yeast. Wineries that often solely rely on these "in-house" strains will sometimes market their wines as being the product of wild or natural fermentations. The (c. 304) Nanfang Caomu Zhuang has the earliest description of winemaking using "herb ferment" (cǎoqū 草麴) wild yeast with rice and various herbs, including the poisonous Gelsemium elegans (yěgé 冶葛). Another use of the term "wild yeast" refers to the non-Saccharomyces genera of yeasts that are present in the vineyard, on the surface of grapevines and of the grapes themselves. Anywhere from 160 to 100,000 colony forming units of wild yeasts per berry could exist in a typical vineyard. These yeasts can be carried by air currents, birds and insects through the vineyard and even into the winery (such as by fruit flies).
Sources: en.wikipedia.org
=== In medicine === Medical use of alkaloid-containing plants has a long history, and, thus, when the first alkaloids were isolated in the 19th century, they immediately found application in clinical practice. Many alkaloids are still used in medicine, usually in the form of salts widely used including the following:
People known to be highly allergic may carry around epinephrine (adrenaline) in the form of a self-injectable EpiPen for the treatment of an anaphylactic shock. For people who experience severe or life-threatening reactions to insect stings, allergy injections composed of increasing concentrations of naturally occurring venom may provide protection against future insect stings.
The grafts are obtained in one or both of the two primary methods of surgical extraction, follicular unit transplantation, colloquially referred to as "strip harvesting", or Follicular Unit Extraction (FUE), in which follicles are transplanted individually. In FUT, a strip of skin containing many follicular units is extracted from the patient and dissected under a stereoscopic microscope. The site of the strip removal is stitched closed. Once divided into follicular unit grafts, each unit is individually inserted into small recipient sites made by an incision in the bald scalp. In the newer technique, roots are extracted from the donor area and divided into strips for transplantation. The strip, two to three millimeters thick, is isolated and transplanted to the bald scalp. After surgery, a bandage is worn for two days to protect the stitched strip during healing. A small strip scar remains after healing, which can be covered by scalp hair growing over the scar.
=== 1960s–1990s === In 1960, Tom Monaghan and his brother, Jim, took over the operation of DomiNick's, an existing location of a small pizza restaurant chain that had been owned by Dominick DeVarti, at 507 Cross Street (now 301 West Cross Street) in Ypsilanti, Michigan, near Eastern Michigan University. The deal was secured by a $500 down payment, after which the brothers borrowed $900 to pay for the store. The brothers planned to split the work hours evenly, but Jim did not want to quit his job as a full-time postman to keep up with the demands of the new business. Within eight months, Jim traded his half of the business to Tom for the Volkswagen Beetle they used for pizza deliveries. By 1965, Tom Monaghan had purchased two additional pizzerias; he now had a total of three locations in the same county. Monaghan wanted the stores to share the same branding, but the original owner forbade him from using the DomiNick's name. One day, an employee, Jim Kennedy, returned from a pizza delivery and suggested the name "Domino's". Monaghan immediately loved the idea and officially renamed the business to Domino's Pizza, Inc. in 1965. The company logo originally had three dots (🁀), representing the three stores in 1965. Monaghan planned to add a new dot with the addition of every new store, but this idea quickly faded, as Domino's experienced rapid growth. Domino's Pizza opened its first franchise location in 1967 and by 1978, the company had expanded to 200 stores.
Sources: en.wikipedia.org
常用质谱测定分子量，再结合肽图或序列分析验证一级结构。单一检测手段一般难以排除结构相近的类似物。多种方法相互印证更为可靠。
低温可以降低水解与聚集的速率，从而延缓降解进程。温度反复波动本身也可能造成相变与样品损失。稳定的储存条件是可重复结果的前提。
分析证书、批次编号、所用检测方法与结果，以及标称储存条件。缺少方法细节的报告难以独立复核。记录完整性决定了追溯能否成立。
Mass spectrometry provides a mass value that can be compared with the expected value, while peptide mapping examines fragmentation patterns. Together these techniques support identity claims better than a single measurement can.