ACTH 片段 is one of those subjects where the details matter more than the headlines. This page pulls together the background, the mechanisms, and the practical points readers ask about most.
Last reviewed on 2025-12-25. Where a claim depends on a specific study, the study is described rather than over-claimed.
Stability depends heavily on physical state. Lyophilized powder held dry, cold and dark retains its content over long periods, whereas dissolved peptide begins to change within days at room temperature. The most cited degradation route is oxidation of the methionine residue, which converts the peptide to a sulfoxide form that elutes differently on chromatography. Hydrolysis of amide bonds and adsorption onto container walls contribute smaller losses. Buffers that exclude oxygen from the headspace slow the oxidation pathway, but no single condition prevents all change indefinitely.
Practical handling follows from those properties. Bulk material is best divided into single-use portions soon after receipt, because each thaw exposes the whole container to moisture and temperature cycling. Vials should be allowed to reach room temperature before opening to prevent condensation on the powder. Low-binding plasticware reduces loss of dilute solutions, and sterile filtration is used when a preparation must remain free of microbial growth. Records of batch number, reconstitution date and storage history are what allow a later analytical result to be interpreted meaningfully.
Semax is a synthetic seven-amino-acid peptide whose sequence extends the ACTH(4-10) fragment with a C-terminal proline-glycine-proline tripeptide. The commonly cited sequence is Met-Glu-His-Phe-Pro-Gly-Pro, giving a molecular formula near C37H51N9O10S and a molecular weight close to 813.9 g/mol. It belongs to the broader class of synthetic ACTH fragments studied for central nervous system effects rather than for adrenal steroid stimulation. In practice the material appears as a lyophilized white powder for laboratory work or as a dilute saline solution in clinical settings.
Development is attributed to researchers at the Institute of Molecular Genetics in Moscow during the early 1980s, building on earlier Soviet work with ACTH fragments. Russian regulatory approval followed for intranasal use, and the compound has remained commercially available there for decades. Most published human data originate from Russian and, later, some Eastern European clinical reports, which are not always accessible in English translation. Outside that region the material is generally handled as a research chemical rather than a licensed medicine.
Regulatory status differs sharply between jurisdictions. In Russia the peptide is registered as a prescription nasal preparation, while agencies such as the United States Food and Drug Administration have not approved it for any indication. Products sold elsewhere are typically labeled for laboratory research only, and such labels shift responsibility for safe handling to the purchaser. Because the same name covers pharmaceutical-grade nasal drops and bulk research powder, identity and purity documentation becomes the main practical concern when comparing sources.
| Property | Value | Notes |
|---|---|---|
| Typical purity specification | ≥ 95 % of peak area by HPLC | Some suppliers quote 98 % or higher |
| Identity confirmation | Mass spectrometry (electrospray or MALDI) | Observed mass is compared with the calculated mass |
| Common analytical method | Reversed-phase HPLC on a C18 column | Acetonitrile and water gradients with trifluoroacetic acid |
| Primary degradation route | Oxidation of the methionine residue | Yields a sulfoxide that separates cleanly on chromatography |
| Storage of dissolved material | Aliquoted and frozen at −20 °C or below | Single-use aliquots avoid repeated temperature cycling |
稳定性主要由水解与氧化两条路径支配。肽键在中性或弱酸性条件下相对稳定，遇到强碱或长时间高温则明显断裂；甲硫氨酸侧链容易被氧化成亚砜，使主峰前移并拉低实际含量。金属离子、光照和反复冻融会进一步促进降解或聚集。冻干粉在低温避光条件下可存放较长时间，配制后的水溶液通常需要冷藏并尽快用完。
纯度评估以反相高效液相色谱为主，通过主峰面积百分比给出粗略结果，再配合电喷雾质谱核对分子量。氨基酸分析可验证组成比例，手性色谱或毛细管电泳用于检查残基构型。常见杂质包括缺失序列的短肽、氧化产物与二聚体。由于多数市售品不附带完整检验报告，独立第三方检测常被用来核实标称值。
从分子层面看，Semax 是线性七肽，没有二硫键、糖基或脂链修饰，N 端为游离氨基，C 端为游离羧基。分子含组氨酸与谷氨酸侧链，因此在水和甲醇等极性溶剂中溶解良好，在非极性溶剂中溶解有限。计算分子量约为 814 Da，与其质子化离子的质荷比吻合，可用于质谱确认。
Semax 是人工设计的七肽，序列为 Met-Glu-His-Phe-Pro-Gly-Pro，骨架取自促肾上腺皮质激素片段 ACTH(4-10)。它于二十世纪八十年代在苏联的分子遗传学研究机构内合成。设计目标是保留该片段与注意力和记忆相关的活性，同时剔除促皮质激素释放等内分泌作用。此后俄罗斯将其登记为药品并进入临床使用。
当时的短肽研究普遍关注能否穿越血脑屏障、在低剂量下产生中枢效应，Semax 属于这一路线。鼻内给药是其主要使用方式，俄语文献报道的适应症涵盖缺血性卒中、短暂性脑缺血发作、认知功能减退以及视神经病变。这些研究大多发表在当地期刊上，样本规模与终点设置同西方试验惯例存在差异，国际同行对其临床证据的强度看法不一。
各国监管态度分化明显。俄罗斯按处方药管理，部分东欧国家留有使用记录；欧盟与美国未批准其作为药物上市，市面流通品通常标注为研究用化学品。身份差异意味着标示含量、纯度与无菌性缺少统一核查。体育领域还牵涉反兴奋剂名录，跨境携带则受目的地药品法规约束。
== Further reading == Ezzati M, Carr BR (January 2015). "Elagolix, a novel, orally bioavailable GnRH antagonist under investigation for the treatment of endometriosis-related pain". Women's Health. 11 (1): 19–28. doi:10.2217/whe.14.68. PMID 25581052. Melis GB, Neri M, Corda V, Malune ME, Piras B, Pirarba S, Guerriero S, Orrù M, D'Alterio MN, Angioni S, Paoletti AM (May 2016). "Overview of elagolix for the treatment of endometriosis". Expert Opin Drug Metab Toxicol. 12 (5): 581–8. doi:10.1517/17425255.2016.1171316. PMID 27021205. S2CID 28684228. Alessandro P, Luigi N, Felice S, Maria PA, Benedetto MG, Stefano A (April 2017). "Research development of a new GnRH antagonist (Elagolix) for the treatment of endometriosis: a review of the literature". Arch. Gynecol. Obstet. 295 (4): 827–832. doi:10.1007/s00404-017-4328-6. PMID 28255765. S2CID 26422467. Perricos A, Wenzl R (September 2017). "Efficacy of elagolix in the treatment of endometriosis". Expert Opin Pharmacother. 18 (13): 1391–1397. doi:10.1080/14656566.2017.1359258. PMID 28737050. S2CID 32467159. Surrey E, Taylor HS, Giudice L, Lessey BA, Abrao MS, Archer DF, Diamond MP, Johnson NP, Watts NB, Gallagher JC, Simon JA, Carr BR, Dmowski WP, Leyland N, Singh SS, Rechberger T, Agarwal SK, Duan WR, Schwefel B, Thomas JW, Peloso PM, Ng J, Soliman AM, Chwalisz K (July 2018). "Long-Term Outcomes of Elagolix in Women With Endometriosis: Results From Two Extension Studies". Obstet Gynecol. 132 (1): 147–160. doi:10.1097/AOG.0000000000002675. PMID 29889764. Taylor HS (July 2018). "Use of Elagolix in Gynaecology".
=== Primary === The development of osteoarthritis is correlated with a history of previous joint injury and with obesity, especially with respect to the hips and knees. Osteoarthritis of the hips and knees is twice as common in those with obesity. Changes in sex hormone levels may play a role in the development of osteoarthritis, as it is more prevalent among post-menopausal women than among men of the same age. Women also tend to have more severe symptoms and imaging findings for hip and knee osteoarthritis as compared to men. Conflicting evidence exists for the differences in hip and knee osteoarthritis in African Americans and Caucasians.
=== Commercial production === Industrial production of vitamin B12 is achieved through fermentation of selected microorganisms. As noted above, the completely synthetic laboratory synthesis of B12 was achieved by Robert Burns Woodward and Albert Eschenmoser in 1972, though this process has no commercial potential, requiring more than 70 steps and having a yield well below 0.01%.
Sources: en.wikipedia.org
The Council of Common Interests (CCI) (Urdu: مشترکہ مفادات ہیئتِ, romanized: Muśtarkāh Mufādāt He'at) is an eight-member federal constitutional body in the government of Pakistan. It is appointed by the president on the prime minister's advice, and resolves the disputes of power sharing between the federation and its provinces (with chief ministers representing their respective provinces). The Council works under the Ministry of Inter Provincial Coordination and is responsible to both houses of the Parliament, the Senate and the National Assembly.
== Scope and terminology == The Food and Agriculture Organization describes the food industry as a broad group of activities connected with the production, processing, supply and distribution of food. Food processing is narrower and concerns the transformation or preservation of food for consumption, while agro-processing can also cover agricultural products outside the food sector. In Bangladesh, official and institutional studies frequently measure the manufacture of food products and beverages rather than the entire food industry. The SEIP labour-market study, for example, restricted its calculations to manufacturing enterprises related to food products and beverages. Market-size, employment and export figures therefore depend on the definition used by the source.
Another common example is the reaction of a primary amine or secondary amine with a carboxylic acid or with a carboxylic acid derivative to form an amide. This reaction is widely used, especially in the synthesis of peptides. On the simple addition of an amine to a carboxylic acid, a salt of the organic acid and base is obtained. To overcome this, the carboxylic acid first needs to be "activated". This is usually done by converting the acid into a more reactive derivative (i.e. anhydride, acid halide) or by using a coupling agent. In some cases, high temperatures (>200 °C) can overcome salt formation by driving off water, without the need for "activation" of the carboxyl group. The downside to this simple reaction is that the compounds may decompose at these elevated temperatures. The carboxylic acid derivatives can be esters, anhydrides, acid halides or any other activated species. The choice of activated carboxyl group or coupling agent can be very important in peptide synthesis, as using the wrong one can lead to racemization.
Of these, humins give the most reliable date as they are insoluble in alkali and less likely to contain contaminants from the sample's environment. A particular difficulty with dried peat is the removal of rootlets, which are likely to be hard to distinguish from the sample material. Soil contains organic material, but because of the likelihood of contamination by humic acid of more recent origin, it is very difficult to get satisfactory radiocarbon dates. It is preferable to sieve the soil for fragments of organic origin, and date the fragments with methods that are tolerant of small sample sizes. Other materials that have been successfully dated include ivory, paper, textiles, individual seeds and grains, straw from within mud bricks, and charred food remains found in pottery.
Sources: en.wikipedia.org
Suppliers normally quote a percentage of total chromatographic peak area, most often from reversed-phase HPLC. That figure says nothing about what the remaining percentage contains, and it depends on the detection wavelength used. A mass spectrometry result is a separate and stronger check on identity.
The methionine residue at the start of the chain is vulnerable to oxidation, producing a sulfoxide variant. Amide bonds can also hydrolyze, though more slowly under neutral conditions. Cold storage, oxygen exclusion and minimization of freeze-thaw cycles slow both processes but do not stop them.
A purity number on a certificate does not establish that a powder is the same product as a registered nasal medicine. Counter-ion content, residual solvents and peptide-related impurities may differ between the two. Independent verification is the only way to narrow that gap.
It is a short synthetic peptide built from seven amino acids: methionine, glutamic acid, histidine, phenylalanine and three prolines. The sequence derives from the 4-10 fragment of adrenocorticotropic hormone with an added proline-glycine-proline tail. No plant or animal extract is involved; the material is produced by solid-phase peptide synthesis.