Everything below concerns shelf life. We keep the language plain, cite what the science says, and separate well-supported claims from open questions.
Last reviewed on 2026-04-10. Where a claim depends on a specific study, the study is described rather than over-claimed.
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.
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.
Identity and purity are confirmed with reversed-phase high-performance liquid chromatography, typically monitored at 214 nanometres where the peptide bond absorbs. Mass spectrometry, either electrospray or MALDI-TOF, verifies molecular mass against the theoretical value and detects truncation or adduct formation. Amino acid analysis and peptide mapping provide additional confirmation when required. The most frequently reported impurities are deletion sequences from incomplete coupling, methionine sulfoxide from oxidation, and dimeric species formed through non-covalent aggregation. Impurity profiles depend strongly on the synthesis and purification route chosen by the producer.
Published research has focused mainly on neurological and cognitive endpoints in animal models, with proposed mechanisms involving brain-derived neurotrophic factor and related signalling pathways. A substantial share of the human data originates from a limited number of research groups, and independent replication in other countries remains sparse. Regulatory status reflects that distribution: the peptide is registered as a medicine in Russia and appears in some neighbouring markets, while elsewhere it is handled as a research chemical without approved therapeutic labelling. Questions about dose-response relationships, long-term effects, and comparability across studies are still open.
| Property | Value | Notes |
|---|---|---|
| Molecular formula | C37H51N9O10S | Contains one methionine sulfur atom |
| Molecular mass | Approximately 814 Da | Consistent with a seven-residue peptide |
| Appearance | White to off-white powder | Typical lyophilized form |
| Solubility | Freely soluble in water | Also soluble in dimethyl sulfoxide |
| Typical storage | -20 °C, desiccated | Limits methionine oxidation |
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。
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。
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.
Solid semax is typically supplied as a lyophilised powder that is hygroscopic and sensitive to moisture, light, and repeated temperature cycling. Long-term storage of the dry peptide is generally recommended at approximately -20 degrees Celsius, while shorter working periods may use refrigeration at 2 to 8 degrees Celsius. Vials should remain tightly closed and desiccated when brought to room temperature, because condensation can damage the material before it is weighed. Dividing a batch into aliquots is preferable to thawing one container repeatedly.
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.
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.
The community centre includes a swimming pool (the only public one in the islands), a sports centre, and a school. A grass football pitch is located by the community centre. A separate building houses the college of further education and the library. A new sports centre is under construction to the south of the town centre, next to a newly-laid floodlit all-weather pitch. Stanley Racecourse, located on the west side of Stanley, holds a two-day horse racing meeting every year on 26 and 27 December. The Christmas races have been held here for over 100 years. Stanley Golf Course has an 18-hole course and a club house. It is also located to the west of Stanley. King Edward VII Memorial Hospital is the islands' main hospital, with doctors' practice and surgery, radiology department, dental surgery and emergency facilities. The Port Stanley Airport operates internal flights, and scheduled international passenger flights operate from the RAF Mount Pleasant military airbase. Stanley is also home to the Falkland Islands Radio Station (FIRS), the Stanley office of the British Antarctic Survey, and the office of the weekly Penguin News newspaper.
== Early life and education == De Duve was born of an estate agent Alphonse de Duve and wife Madeleine Pungs in the village of Thames Ditton, near London. His parents fled Belgium at the outbreak of the First World War. After the war in 1920, at age three, he and his family returned to Belgium. He was a precocious boy, always the best student (primus perpetuus as he recalled) in school, except for one year when he was pronounced "out of competition" to give chance to other students. He was educated by the Jesuits at Onze-Lieve-Vrouwinstituut in Antwerp, before studying at the Catholic University of Louvain in 1934. He wanted to specialize in endocrinology and joined the laboratory of the Belgian physiologist Joseph P. Bouckaert, whose primary interest was one insulin. During his last year at medical school in 1940, the Germans invaded Belgium. He was drafted to the Belgian army, and posted in southern France as medical officer. There, he was almost immediately taken as prisoner of war by Germans. His ability to speak fluent German and Flemish helped him outwit his captors. He escaped back to Belgium in an adventure he later described as "more comical than heroic". He immediately continued his medical course, and obtained his MD in 1941 from Leuven. After graduation, de Duve continued his primary research on insulin and its role in glucose metabolism. He (with Earl Sutherland) made an initial discovery that a commercial preparation of insulin was contaminated with another pancreatic hormone, the insulin antagonist glucagon.
== Prime ministers == The official counting of prime ministers starts with the first president of the Council of Ministers of the constitutional monarchy. The first column shows the name (and title during the monarchy) of each office holder, with the second and third column showing the start and end of term. A fourth column counts the duration of each term. The next column shows each election won by each Prime Minister, followed by the color and political affiliation of the holder. Then, there's a column listing each constitutional governments headed by each Prime Minister, and finally, a last column showing the head of state during the term of each office holder, between 1834 and 1910, a Monarch, and since 1910, a President. The colors indicate the political affiliation: No party/independent Chartist/Chamorro Septemberist Regenerator Historic Reformist Progressist Liberal Regenerator
In order to exert their function, enzymes need to assume their correct protein fold (native fold) and tertiary structure. To maintain this defined three-dimensional structure, proteins rely on various types of interactions between their amino acid residues. If these interactions are interfered with, for example by extreme pH values, high temperature or high ion concentrations, this will cause the enzyme to denature and lose its catalytic activity. A tighter fit between an active site and the substrate molecule is believed to increase the efficiency of a reaction. If the tightness between the active site of DNA polymerase and its substrate is increased, the fidelity, which means the correct rate of DNA replication will also increase. Most enzymes have deeply buried active sites, which can be accessed by a substrate via access channels. There are three proposed models of how enzymes fit their specific substrate: the lock and key model, the induced fit model, and the conformational selection model. The latter two are not mutually exclusive: conformational selection can be followed by a change in the enzyme's shape. Additionally, a protein may not wholly follow either model. Amino acids at the binding site of ubiquitin generally follow the induced fit model, whereas the rest of the protein generally adheres to conformational selection. Factors such as temperature likely influences the pathway taken during binding, with higher temperatures predicted to increase the importance of conformational selection and decrease that of induced fit.
Sources: en.wikipedia.org
In the case of tyrocidine, ring closure has been shown to be highly favorable due to 4 H-bonds helping the decapeptide backbone to adopt a stable conformation (See figure 5). This intramolecular cyclization occurs in a head-to-tail fashion involving the N-terminus of the D-Phe1 and the C-terminus of the L-Leu10 (See figure 4).
=== Pharmacokinetics === There are small differences in the pharmacokinetics between different sublingual buprenorphine/naloxone products. These differences may require changes in dose when a person switches from one product to another. The buprenorphine/naloxone sublingual film (e.g. trade name Suboxone) achieves higher buprenorphine maximum plasma concentrations (Cmax) and area under the curve (AUC, a measure of total drug exposure) than the original buprenorphine/naloxone sublingual tablets at equal doses. For example, at a buprenorphine/naloxone dose of 8 mg/2 mg, the buprenorphine Cmax after a single dose of the original tablet formulation is around 3 ng/mL whereas that of the 8 mg/2 mg film formulation is around 3.55 ng/mL. The Zubsolv trade name sublingual tablets have higher buprenorphine bioavailability than the original sublingual tablets, while the Bunavail trade name buccal films have the highest bioavailability. For example, a single dose of Bunavail 4.2 mg/0.7 mg achieves a Cmax around 3.41 ng/mL.
== External links == From Chechnya To Syria Ali ash-Shishani: “Like all Chechens in Syria, I miss Chechnya” Russia: Is Damascus’ Claim Of “1,700 Chechens” Fighting in Syria Correct? The end of Chechen jihadis in Syria Europe’s Chechen Foreign Fighters Archived 17 December 2021 at the Wayback Machine Syria: Motorcycle Mujahideen — Diary Of A Chechen Jihadi in Aleppo Chechen extremists aiding opposition fighters in Syria Chechen commander for Al Nusrah Front reported killed in fighting against Syrian forces Archived 14 May 2019 at the Wayback Machine The Chechens of Syria Chechnya’s Veteran Fighters Have Their Backs to the Wall Combat in Cities: The Chechen Experience in Syria HANNIBAL RISING: THE NEW LEADER OF THE JIHADIST PMC MALHAMA TACTICAL HTS Usir Pemimpin Jihad Chechnya Dari Idlib Chechen and north Caucasian militants in Syria - Atlantic Council Battle-Tested Chechens Drive Islamic State Gains The Impact of Chechen and North Caucasian Militants in Syria Q&A: Would ISIS Fighters Return to Georgia?
=== Genetics === Two-thirds of families with a history of type 2 diabetes report more than one family member having MASLD. There is a higher risk of fibrosis for family members where someone was diagnosed with MASH. Asian populations are more susceptible to metabolic syndrome and MASLD than their Western counterparts. Hispanic persons have a higher prevalence of MASLD than white individuals, whereas the lowest prevalence is observed in black individuals. MASLD is twice as prevalent in men as in women, which might be explained by lower levels of estrogen in men. Genetic variations in two genes are associated with MASLD: non-synonymous single-nucleotide polymorphisms (SNPs) in PNPLA3 and TM6SF2. Both correlate with MASLD presence and severity, but their roles for diagnosis remain unclear. Although MASLD has a genetic component, the American Association for the Study of Liver Diseases (AASLD) does not recommend screening family members as there is not enough confirmation of heritability, although there is some evidence from familial aggregation and twin studies.
=== 1990s === In 1990, following the Grace's Grace Energy public offering in 1989, Grace Energy purchased all of the minority shares of its common stock of its Grace Drilling from Panhandle Eastern Corporation, which gave Grace Energy 99.45% ownership of Grace Drilling. In 1992, Grace sold its 21%-percent interest of Grace Cocoa (Grace Cocoa Associates, LP,), for $300 million. Grace Cocoa was classified as a discontinued operation by Grace in 1993, but due to market conditions, the Grace later sold the rest of the company along with its paper drying, polymer, and filtration units in 1996 for over $300 million. In 1995, Albert Costello became the CEO of the company, replacing J. Peter Grace, as well as became the new president, replacing J.P. Bolduc. Costello was the former CEO and chairman of the board at American Cyanamid (1993-1994). Bolduc (CEO from 1993-1995) was considered to have successfully sold off some of the unprofitable noncore businesses and to have expanded some of the successful businesses within the company at that point in time.
Sources: en.wikipedia.org
It is registered as a pharmaceutical product in Russia, where it is typically supplied as a nasal solution. In most other countries it is not an approved drug and is traded as a research chemical instead. Approval status depends entirely on the jurisdiction involved.
Most published work uses intranasal administration, matching the route of the registered Russian formulation. Some animal experiments use intravenous or intraperitoneal injection. The route matters because the intact peptide is cleared rapidly from blood, so exposure differs between methods.
A purity value describes the share of the powder accounted for by the target peptide, usually by high-performance liquid chromatography. It does not confirm that the sequence is correct, which requires mass spectrometry or amino acid analysis. Purity and identity are separate checks.
Reversed-phase HPLC gives the main purity figure, most often with UV detection near 214 nanometres. Mass spectrometry then confirms the molecular mass. Together the two methods distinguish a correct sequence from a closely related impurity.