Everything below concerns lyophilised powder. We keep the language plain, cite what the science says, and separate well-supported claims from open questions.
Last reviewed on 2025-10-19. Where a claim depends on a specific study, the study is described rather than over-claimed.
多数实验室与市售的 Semax 以冻干粉形式提供。冻干粉通常建议保存在 -20 °C 或更低温度下，同时避免光照与反复升温。短期运输有时采用冷藏条件，但长期保存仍以冷冻为主。分包操作应尽量减少开盖次数，以降低吸湿和微生物污染的风险。开封后若未一次用完，建议在干燥环境中密封并尽快放回低温储存。
溶液状态的稳定性明显低于冻干粉。肽类在水溶液中可能经历水解、氧化与聚集，其中甲硫氨酸和天冬酰胺等残基常是敏感位点。Semax 含有甲硫氨酸，因此氧化风险相对突出。工作液一般主张现配现用，或冷藏并在数日内用尽。缓冲液种类、pH 和离子强度都会影响降解速率，而关于最佳条件的公开数据并不统一。
Development of the compound took place in the Soviet Union during the 1980s, largely through peptide research groups affiliated with the Shemyakin-Ovchinnikov Institute and Moscow State University. Investigators screened fragments of adrenocorticotropic hormone for activity on the central nervous system while attempting to separate cognitive effects from hormonal ones. The shortened sequence was selected because it retained behavioral activity in animal models without stimulating corticosteroid release. Early publications described the molecule as an ACTH(4-10) analog.
Published research on this peptide originates mainly from Russian laboratories, and the wider international literature is comparatively thin. Studies have used rodent models of stroke, hypoxia, and memory tasks, with a smaller number of human trials reported. Reported outcomes include changes in attention and memory measures, along with effects on neurotrophic factor expression in some experiments. Small sample sizes, inconsistent dosing protocols, and limited independent replication are widely noted limitations, so the strength of the clinical evidence remains an open question.
| Property | Value | Notes |
|---|---|---|
| 外观 | 白色至类白色粉末 | 常见于冻干制剂 |
| 溶解度 | 易溶于水 | 在极性溶剂中一般也可溶 |
| 建议储存温度 | -20 °C | 冻干粉，避光密封 |
| 常见分析手段 | 反相高效液相色谱 | 常与质谱联用 |
| 主要降解路径 | 水解与氧化 | 溶液状态更显著 |
Dissolution is normally performed in water, phosphate-buffered saline, or normal saline, since the peptide is freely soluble in aqueous media and is rarely handled with strong organic solvents. Solution pH should be kept near neutral, because extreme acidity or alkalinity accelerates backbone hydrolysis and encourages oxidation of the methionine side chain. Once dissolved, the material is less stable than the dry powder and is commonly divided into single-use portions and frozen. Buffers containing primary amines, such as Tris, are often avoided because of possible side reactions.
Purity assessment relies mainly on reversed-phase high-performance liquid chromatography, which separates the target heptapeptide from truncated sequences, deletion analogues, and oxidised forms. Mass spectrometry, usually coupled to liquid chromatography, confirms identity through the expected molecular ion and reveals modifications such as methionine sulfoxide formation. Amino acid analysis can verify composition, and tandem mass spectrometry supports sequence confirmation. Ultraviolet detection near 254 to 280 nanometres is convenient because the phenylalanine and histidine residues absorb in that region. Nuclear magnetic resonance is rarely used for routine release testing.
Common degradation pathways include oxidation of the methionine side chain, hydrolysis of the peptide backbone, and aggregation under unfavourable pH or concentration. Stability studies typically monitor the main peak by chromatography and report total related substances as a percentage. Because no official monograph exists, acceptance criteria vary between laboratories, and reported purity values are not directly comparable across suppliers. Analysts therefore document the method, column, and detection wavelength alongside each result, and open questions remain about how much biological activity the oxidised forms retain.
Laboratory descriptions of the material are consistent across suppliers. It appears as a white to off-white lyophilized powder that dissolves readily in water and in polar organic solvents such as dimethyl sulfoxide. Aqueous solutions are clear and colorless at low concentrations. Because the peptide contains methionine, oxidation at the sulfur atom is a recognized degradation pathway, and handling notes usually call for protected, desiccated storage. Reported purity for research-grade lots is generally above 95 percent as measured by reversed-phase high-performance liquid chromatography.
The compound is registered in Russia as a pharmaceutical product, most commonly formulated as a nasal solution, and has been used in that setting since the 1990s. Outside that jurisdiction it is generally handled as a research chemical rather than an approved medicine. Regulatory status therefore differs sharply between countries, and material sold internationally may not correspond to the Russian pharmaceutical formulation. Documentation with commercial samples is typically limited to a certificate of analysis covering purity and identity, not clinical status or local legal classification.
Semax is a synthetic heptapeptide with the sequence Met-Glu-His-Phe-Pro-Gly-Pro. It corresponds to the ACTH(4-7) fragment extended at the C-terminus by a Pro-Gly-Pro tripeptide, an addition intended to slow enzymatic breakdown. The molecular formula is C37H51N9O10S and the molecular mass is approximately 814 daltons. In the literature it is often described as an ACTH(4-10) analog, although that label reflects a naming convention as much as a precise structural relationship. The compound was developed in Russia and remains most closely associated with that research tradition.
The 1988 US presidential elections lent new urgency to the negotiations, which had recently stalled after six consecutive rounds of talks in Brazzaville. Angola and Cuba had gambled heavily on a victory for Michael Dukakis and the Democratic Party during the US elections, hoping that this would spell the end of US aid to UNITA and a harder line on South Africa. At the time of the Geneva Protocol, dos Santos had commented that "if the Democrats had won the elections, there would be a readjustment in US policy, particularly on Southern Africa". The election of Republican candidate George H. W. Bush had the effect of persuading the Angolan and Cuban delegations to be more flexible. Crocker reiterated on several occasions that a new US administration meant changes in personnel and basic policy review, and pressed them not to waste months of effort. Three days after the US election results were released, the parties reconvened in Geneva and within the week had agreed to a phased Cuban withdrawal over the course of twenty seven months. In exchange, South Africa pledged to begin bestowing independence on South West Africa by 1 November 1989. On 13 December 1988, South Africa, Angola, and Cuba signed the Brazzaville Protocol, which affirmed their commitment to these conditions and set up a Joint Military Monitoring Commission (JMMC) to supervise the disengagement in Angola. The JMMC was to include Soviet and US observers. All hostilities between the belligerents, including PLAN, were to formally cease by 1 April 1989.
nitrogenous base Sometimes used interchangeably with nucleobase or simply base. Any organic compound containing a nitrogen atom that has the chemical properties of a base. Five particular nitrogenous bases – adenine (A), guanine (G), cytosine (C), thymine (T), and uracil (U) – are especially relevant to biology because they are components of nucleotides, which are the primary monomers that make up nucleic acids.
==== Quantification ==== Polyphenolic content in vitro can be quantified by volumetric titration. An oxidizing agent, permanganate, is used to oxidize known concentrations of a standard tannin solution, producing a standard curve. The tannin content of the unknown is then expressed as equivalents of the appropriate hydrolyzable or condensed tannin. Some methods for quantification of total polyphenol content in vitro are based on colorimetric measurements. Some tests are relatively specific to polyphenols (for instance the Porter's assay). Total phenols (or antioxidant effect) can be measured using the Folin–Ciocalteu reaction. Results are typically expressed as gallic acid equivalents. Polyphenols are seldom evaluated by antibody technologies. Other tests measure the antioxidant capacity of a fraction. Some make use of the ABTS radical cation which is reactive towards most antioxidants including phenolics, thiols and vitamin C. During this reaction, the blue ABTS radical cation is converted back to its colorless neutral form. The reaction may be monitored spectrophotometrically. This assay is often referred to as the Trolox equivalent antioxidant capacity (TEAC) assay. The reactivity of the various antioxidants tested are compared to that of Trolox, which is a vitamin E analog. Other antioxidant capacity assays which use Trolox as a standard include the diphenylpicrylhydrazyl (DPPH), oxygen radical absorbance capacity (ORAC), ferric reducing ability of plasma (FRAP) assays or inhibition of copper-catalyzed in vitro human low-density lipoprotein oxidation.
=== 13 May === Ukrainian outlet Rubryka reported that the DeepState map indicated that Russian forces had taken control over the village of Zelene, while the village of Lukiantsi was almost wholly occupied. Ukrainian forces meanwhile claimed to have killed over 100 Russian soldiers in the last 24 hours in northern Kharkiv Oblast. Some five Russian battalions were reported to be involved in Vovchansk. Ukrainian officials acknowledged that Russian forces had made "tactical gains". Russian forces subsequently claimed to have entered Vovchansk. An explosion was reported in Sorokyne, occupied Luhansk Oblast, with the Russian-installed governor claiming the deaths of three people in what he called a missile strike and the Ukrainian-installed governor attributing it to an explosion at an ammunition depot. Russia claimed to have shot down 31 drones over Crimea and Lipetsk, Belgorod, and Kursk Oblasts, which also led to the closure of the Crimean Bridge for several hours after the Russian Defence Ministry claimed that four Storm Shadow missiles and seven drones were shot down over Crimea. Ukrainian media reported that the SBU was behind the strikes. Russian officials claimed that one person was killed in Kursk Oblast. Denis Kharitonov, a member of the Astrakhan Oblast legislature from the United Russia party, claimed to have survived a car bombing while driving as a soldier in occupied Ukraine. Ukrainian forces claimed to have shot down a Russian Ka-52 helicopter and an Su-25 jet over Donetsk Oblast.
Sources: en.wikipedia.org
=== MSEIRS model === An MSEIRS model is similar to the MSEIR, but the immunity in the R class would be temporary, so that individuals would regain their susceptibility when the temporary immunity ended.
The Gamat, which is a Malay word for sea cucumber (holothuroidea), refers to medicinal remedies derived from several species of the sea cucumber family. It has been used traditionally by the Malays and local indigenous in Malaysia to relieve back pain, treating bruise, minor wounds and burns, as well as a tonic to provide extra energy to the body. A research conduct by Universiti Malaysia Sabah (UMS) in 2007 to find out the usage of traditional medicine among the ethnic groups in Sabah in a public market in the eastern coast of Tawau District found that the Bugis with the most usage with 40%, followed by Sama-Bajau with 28%, with Gamat oil (minyak gamat) and Eucalyptus oil (minyak kayu putih) are most commonly used by the community.
Use of this detection method is primarily found in the electrowetting of dielectric DMFs, where the sensing electrode apparatus can be reconfigurable and has a longer lifetime while still producing accurate results.
Sources: en.wikipedia.org
一般不建议常温长期保存。多数说明指向 -20 °C 冷冻避光。常温运输通常被视为短期可接受，但会加快降解风险。
公开资料对此没有统一答案。普遍建议现配现用，或冷藏并在数日内用完。含甲硫氨酸的序列更易氧化，放置时间越长风险越高。
反相高效液相色谱是最常用的手段，配合质谱确认分子量。氨基酸组成分析和肽图分析可补充序列层面的验证。
It is a synthetic peptide of seven amino acids. Its backbone corresponds to a fragment of adrenocorticotropic hormone extended at the carboxyl end. The material is distributed as a lyophilized solid for laboratory use.