A practical reference on single-use aliquot: what it is, how it behaves, what the literature reports, and where the honest uncertainties sit.
This page was last updated on 2025-12-26 and is reviewed periodically as new material appears.
Once dissolved, the peptide is considerably less stable than the solid. Aqueous solutions are usually prepared at neutral to slightly acidic pH, filtered, and divided into single-use aliquots before freezing. Repeated freeze-thaw cycles are a common cause of avoidable loss and are best prevented by never refreezing a thawed aliquot. Adsorption to plastic and glass surfaces can lower the measured concentration of dilute solutions, particularly below roughly 0.1 mg/mL. Buffer choice, salt content, and container material all influence how much peptide remains detectable after storage.
Identity and purity are established with standard peptide methods. Reversed-phase HPLC with ultraviolet detection near 214 nm resolves the parent peak from deletion and truncation byproducts, and reports typically quote a main-peak percentage. Mass spectrometry by electrospray or MALDI-TOF confirms the expected molecular mass, while amino acid analysis or peptide mapping can verify composition when the sequence itself is in question. A certificate of analysis that pairs a chromatogram with a mass spectrum is more informative than a purity figure alone. Counter-ion content and residual solvents are separate specifications and are frequently omitted.
Semax is normally supplied as a lyophilized powder, and that form is the most stable. Suppliers commonly recommend storage at -20 °C in a desiccated container protected from light, with short-term handling at room temperature limited to weighing and transfer. Powder that has absorbed moisture degrades faster, so vials should be warmed to ambient temperature before opening to prevent condensation on the contents. Hygroscopic behavior is typical of short hydrophilic peptides, and humidity control matters more than temperature alone for long-term retention.
Semax is a synthetic heptapeptide whose sequence is Met-Glu-His-Phe-Pro-Gly-Pro. The first four residues correspond to the ACTH(4-10) fragment, while the terminal Pro-Gly-Pro extension was added to improve metabolic stability. Its molecular formula is C37H51N9O10S and its monoisotopic mass is approximately 813.9 Da. The compound is classified as a peptide research chemical and as a registered pharmaceutical product in Russia, but it does not hold marketing approval in the European Union or the United States. Naming conventions vary across supplier catalogs.
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 |
|---|---|---|
| Solid storage temperature | -20 °C or below | Desiccated and protected from light |
| Solution storage temperature | -80 °C as single-use aliquots | Avoid repeated freeze-thaw cycles |
| Purity assessment method | RP-HPLC, around 214 nm | Reported as main-peak area percent |
| Identity confirmation method | ESI-MS or MALDI-TOF | Measured mass compared with calculated mass |
| Common synonyms | ACTH(4-10) analog; Met-Glu-His-Phe-Pro-Gly-Pro | Also written as Semaxum in some sources |
Published research covers ischemic stroke, traumatic brain injury, cognitive impairment, optic nerve conditions and attention-related measures. Much of the human evidence comes from small trials conducted in one country, which limits how far the results generalize. Animal models supply the larger share of the data, and effects seen in rodents do not transfer automatically to people. Reviews have noted that methodological reporting is often incomplete, making it difficult to pool results or compare treatment schedules across studies.
Pharmacokinetic accounts emphasize rapid breakdown. After intravenous dosing the intact peptide disappears from blood within minutes, and nasal delivery produces low but measurable concentrations. Metabolites rather than the parent molecule may account for part of the observed activity, although the relative contribution is unresolved. Dosing in the literature varies widely and no optimal schedule has been agreed. These gaps are regularly cited as a reason the findings have not produced broad clinical adoption beyond the original research setting.
Proposed mechanisms center on neurotrophic signaling rather than on classical melanocortin receptor activation. Rodent experiments have reported shifts in the expression of brain-derived neurotrophic factor and nerve growth factor after administration, together with changes in the associated receptor systems. Several authors argue that the peptide acts largely through its degradation products and their interaction with peptidergic pathways, but this remains a hypothesis rather than a settled finding. No single molecular target has been identified in a way that the field broadly accepts.
研究兴趣主要集中在神经营养因子相关的路径上，包括脑源性神经营养因子与神经生长因子的表达变化。部分实验报告称在特定条件下观察到这些因子的水平上升，但具体信号通路和剂量依赖关系仍未完全厘清。多数公开数据来自细胞模型和动物实验，人体对照研究数量有限。因此，该化合物的作用机制在文献中属于活跃讨论，而非已经确立的定论。
Semax 是一种人工合成的七肽，氨基酸序列为 Met-Glu-His-Phe-Pro-Gly-Pro，单字母缩写记作 MEHFPGP。它被归类为促肾上腺皮质激素片段 ACTH(4-10) 的结构类似物，但并不天然存在于生物体内。母体片段 ACTH(4-10) 的序列为 Met-Glu-His-Phe-Arg-Trp-Gly，Semax 替换了中间两个残基，并在羧基端延长了 Pro-Gly-Pro 三肽。这种延长被普遍认为能提升分子对肽酶的耐受性。
该化合物于二十世纪八十年代在俄罗斯被开发，相关工作由俄罗斯科学院分子遗传学研究所的研究团队主导。开发目标并非复制 ACTH 的完整激素活性，而是寻找保留其神经作用方向、同时去除促肾上腺皮质激素释放效应的短肽片段。研究记录显示，这一方向促成了多个相关短肽的合成与筛选，而 Semax 是其中被研究最广泛的一个。当地文献常以 Семакс 这一名称指代它。
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.
Polyamides can also be synthesized from dinitriles using acid catalysis via an application of the Ritter reaction. This method is applicable for preparation of nylon 1,6 from adiponitrile, formaldehyde and water. Additionally, polyamides can be synthesized from glycols and dinitriles using this method as well.
Committee on Herbal Medicinal Products (HMPC) (22 May 2012). "Assessment report on Citrus bergamia Risso et Poiteau, aetheroleum Final" (PDF). European Medicines Agency (EMA). Archived from the original (PDF) on 8 April 2014. Retrieved 7 April 2014. Committee on Herbal Medicinal Products (HMPC) (22 May 2012). "List of references supporting the assessment of Citrus bergamia Risso et Poiteau, aetheroleum Final" (PDF). European Medicines Agency (EMA). Archived from the original (PDF) on 8 April 2014. Retrieved 7 April 2014.
Hence, the majority of the carbon dioxide is not converted into carbonic acid, but remains as CO2 molecules, not affecting the pH. The relative concentrations of CO2, H2CO3, and the deprotonated forms HCO3– (bicarbonate) and CO32– (carbonate) depend on the pH. As shown in a Bjerrum plot, in neutral or slightly alkaline water (pH > 6.5), the bicarbonate form predominates (>50%) becoming the most prevalent (>95%) at the pH of seawater. In very alkaline water (pH > 10.4), the predominant (>50%) form is carbonate. The oceans, being mildly alkaline with typical pH = 8.2–8.5, contain about 120 mg of bicarbonate per liter. Being diprotic, carbonic acid has two acid dissociation constants, the first one for the dissociation into the bicarbonate (also called hydrogencarbonate) ion (HCO3–):
Sources: en.wikipedia.org
=== History of extension of indications === In May 2022, the indication was updated to include the treatment of eosinophilic esophagitis in people aged twelve years of age and older weighing at least 40 kilograms (88 lb). In September 2022, the indication was updated to include the treatment of adults with prurigo nodularis (PN). In March 2023, the European Medicines Agency approved dupilumab for the treatment of severe atopic dermatitis in children aged six months to five years who are candidates for systemic therapy. In September 2024, the indication was updated to include the treatment of chronic rhinosinusitis with nasal polyps for adolescents, and chronic obstructive pulmonary disease. In April 2025, the indication was updated to include the treatment of chronic spontaneous urticaria. In June 2025, an additional indication for treatment of bullous pemphigoid was also approved.
=== Spukie === The term spukie ("spukkie" or "spuckie") is unique to the city of Boston and derives from the Italian word spuccadella, meaning "long roll". The word spuccadella is not typically found in Italian dictionaries, which may suggest that it could be a regional Italian dialect, or possibly a Boston Italian-American innovation. Spukie is typically heard in parts of Dorchester and South Boston. Some bakeries in Boston's North End neighborhood have homemade spuccadellas for sale.
When the 1956 Highway Act mandated new highways routed through Detroit, the Black Bottom and Paradise Valley areas were an ideal placement; deconstruction of the site had already been started, and the political clout of slum clearance was more powerful than the limited ability residents had to advocate against the placement. Though it faced urban poverty and overcrowding, the Black Bottom neighborhoods were an exciting mix of culture and innovation, with the economic district boasting approximately 350 black-owned businesses. The downtown area is often described as if Motown music played even from the pipes in the street. But when highway projects were announced, sometimes years before construction started and sometimes warning only thirty days in advance, the property values for those who did own land disappeared. The forced relocation condemned many residents to even harsher poverty, and the local government commissions made few efforts to assist families in relocation. It was difficult enough for the thousands of persons displaced to find new housing in a time when restrictive covenants, even though technically outlawed in 1948, were deftly and covertly written into many of Detroit's surrounding neighborhoods. It was even harder for business owners to relocate their life's work. The lasting ramifications of the highway construction are still felt by the black business sector in Detroit today.
Photograph A. – Open rhinoplasty: At rhinoplasty's end, after the plastic surgeon has sutured (closed) the incisions, the corrected (new) nose will be dressed, taped, and splinted immobile to permit the uninterrupted healing of the surgical incisions. The purple-ink guidelines ensured the surgeon's accurate cutting of the defect correction plan. Photograph B. – Open rhinoplasty: The new nose is prepared with paper tape in order to receive the metal nasal-splint that will immobilize it to maintain its correct shape as a new nose.
Sources: en.wikipedia.org
Chinampa – Chinampas, sometimes called "floating gardens," were highly productive agricultural systems developed in the Valley of Mexico. The Aztecs built and used them extensively for agriculture in and around the lakes of the Valley of Mexico. Chocolate – Produced from the seed of the tropical Theobroma cacao tree, cacao was first cultivated by the Olmec of Mesoamerica as early as 1900 BCE. The Maya and Aztec developed chocolate into a frothy ceremonial beverage. Chunkey – a Native American game where a person rolls a hoop covered in a leather strap framework and tries to hit it with spears or arrows. This may have inspired the sport of skeet shooting. Compass (possibly) – the Olmecs are known to have knowledge of magnetism. The discovery of a hematite artifact has led many experts to believe that Olmec invented the compass 1,000 years before the Chinese did, although some still are not convinced. Compulsory education – the Aztec Triple Alliance, which ruled from 1428 to 1521 CE, is considered to be the first state to implement a system of universal compulsory education. Corn beer – brewed in the Andes, it is of pre-Incan origin from the Wari culture. Cornmeal – an unsoaked meal (coarse flour) ground from dried maize. It is a common staple food, and is ground to fine, medium, and coarse consistencies. Cranberries – Native Americans were the first to domesticate and grow cranberries in the north east coast of the United States.
The insulin receptor's endogenous ligands include insulin, IGF-I and IGF-II. Using a cryo-EM, structural insight into conformational changes upon insulin binding was provided. Binding of ligand to the α-chains of the IR dimeric ectodomain shifts it from an inverted V-shape to a T-shaped conformation, and this change is propagated structurally to the transmembrane domains, which get closer, eventually leading to autophosphorylation of various tyrosine residues within the intracellular TK domain of the β-chain. These changes facilitate the recruitment of specific adapter proteins such as the insulin receptor substrate proteins (IRS) in addition to SH2-B (Src Homology 2 - B ), APS and protein phosphatases, such as PTP1B, eventually promoting downstream processes involving blood glucose homeostasis. Strictly speaking the relationship between IR and ligand shows complex allosteric properties. This was indicated with the use of a Scatchard plots which identified that the measurement of the ratio of IR bound ligand to unbound ligand does not follow a linear relationship with respect to changes in the concentration of IR bound ligand, suggesting that the IR and its respective ligand share a relationship of cooperative binding. Furthermore, the observation that the rate of IR-ligand dissociation is accelerated upon addition of unbound ligand implies that the nature of this cooperation is negative; said differently, that the initial binding of ligand to the IR inhibits further binding to its second active site - exhibition of allosteric inhibition.
The "free" and "bound" lipids do not differ significantly in their fatty acid composition. In addition to lactobacillic acid with a share of 31%, palmitic acid (C16:0), stearic acid (C18:0) and cis-vaccenic acid (C18:1 cis-11) with a proportion of 37%, 2% and 20% respectively. The test results of the newly discovered fatty acid showed that it is a saturated fatty acid. It is stable towards oxidizing agents that would react with a double bond in the carbon chain. In the reaction with hydrogen bromide (HBr), however, an addition of HBr occurs in the molecule. Hydrogenation is also possible, resulting in several isomers fatty acids with the molecular formula C19H38O2, one of which has been identified as nonadecanoic acid. The other compound is a branched-chain fatty acid with a methyl group as a branch (methyloctadecanoic acid), although the scientists could not distinguish at the time whether one or more isomers of it were present. Based on the results of the chemical and physical (infrared spectroscopy and X-ray diffraction) methods for structure elucidation, a saturated fatty acid with a cyclopropane ring in the carbon chain was proposed as the structure.
America's Taco Shop – a restaurant chain with locations only in Arizona. Baja Fresh – a chain of fast-casual Tex Mex restaurants in the United States, Portugal and Kuwait. Blimpie – an American submarine sandwich chain with locations in the United States and Kuwait Cereality – a chain with stores in Texas, West Virginia, Minnesota and Ohio; also formerly had stores in Illinois. Cold Stone Creamery – an ice cream parlor restaurant chain with stores in Bahrain, Canada (partnership with Burger King/Tim Hortons from 2008 to 2014 now terminated), China, Denmark, Egypt, India, Indonesia, Japan, Kuwait, Mexico, Nigeria, Oman, Qatar, South Korea, Taiwan, United Arab Emirates, United States, Philippines, Kenya, Bangladesh, Pakistan, Finland, Jordan, Norway, Saudi Arabia, Sweden, Vietnam, Singapore and Lebanon Frullati Cafe & Bakery – chain with stores in Kuwait and the United States. Grabbagreen – a chain of restaurants offering healthy foods and smoothies. Great Steak – a restaurant chain with locations in Canada, Mexico, Kuwait and the United States. Founded 1982; formerly "Great Steak & Potato Company". In 2000, it had 225 locations. Sold to Kahala Brands in 2004; expansion planned into South Korea. Johnnie's New York Pizzeria – restaurant chain with stores in California, Florida, Oregon, and Texas. Kahala Coffee Traders (California, Utah) La Salsa – a chain of fast-casual Tex Mex restaurants in the United States Maui Wowi Hawaiian – chain with stores in the United States, Mexico, Saudi Arabia and the United Arab Emirates.
=== Membrane and self-assembling peptide studies === Membrane proteins and self-assembly properties of certain proteins can be studied under this technique, due to being a label-free calorimeter. Membrane proteins are known to have difficulties with selection of proper solubilization and purification protocols. As ITC is a non-destructive calorimetric tool, it can be used as a detector to locate the fraction of protein with desired binding sites, by binding a known binding ligand to the protein. This feature also applies in studies of self-assembling proteins, especially in use of measuring thermodynamics of their structural transformation.
Sources: en.wikipedia.org
Each freeze-thaw cycle can degrade a fraction of the peptide and promote aggregation. Dividing a stock solution into single-use volumes removes repeated cycling as a variable. It also limits the time a thawed solution spends at room temperature.
A high main-peak percentage says little about identity, counter-ion content, or residual solvents. It also does not distinguish an isomer or a closely eluting analog. Mass confirmation and the accompanying documentation cover those gaps.
Salt form changes mass, solubility, and hygroscopicity, and acetate and trifluoroacetate salts behave differently in solution. Storage guidance still centers on -20 °C for powder and lower temperatures for solutions. The certificate should state which salt is present.
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.