nasal formulation raises a handful of sensible questions. This page answers them in order, starting with the fundamentals and moving to applications.
This page was last updated on 2026-02-20 and is reviewed periodically as new material appears.
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.
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.
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.
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.
| Property | Value | Notes |
|---|---|---|
| Typical analytical method | Reversed-phase HPLC with UV detection | Separates target peptide from truncated and oxidised forms |
| Identity confirmation | LC-MS or ESI-MS | Compares observed and calculated molecular ion |
| Primary degradation route | Methionine oxidation | Forms the sulfoxide; monitored as an early-eluting peak |
| Short-term storage | 2 to 8 degrees Celsius | Applies to working vials and reconstituted portions |
| Common synonyms | ACTH(4–10) analogue, MEHFPGP | Descriptive names used in laboratory catalogues |
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。
Semax is a synthetic heptapeptide with the sequence Met-Glu-His-Phe-Pro-Gly-Pro. Its design combines the ACTH(4-7) core fragment with a C-terminal Pro-Gly-Pro extension, a modification intended to improve stability and prolong activity. The molecule is hydrophilic, carries no lipid chains or glycosylation, and has a theoretical mass just over 810 daltons in its free form. All seven residues are proteinogenic amino acids, so no non-natural building blocks appear in the backbone. A free N-terminal methionine and C-terminal proline define the unmodified parent peptide.
The compound was developed during the 1980s at the Institute of Molecular Genetics in Moscow as part of research on fragments of adrenocorticotropic hormone. Early work examined short ACTH-derived sequences that retained neurotrophic effects while lacking the endocrine activity of the full hormone. Semax entered clinical use in Russia during the 1990s, where it received registration for several neurological indications. Outside that region it remained primarily a laboratory research material rather than an approved therapeutic. English-language literature on it grew more slowly and frequently cited the original Russian studies.
Terminology around the compound varies by source. It appears in catalogues and papers as Semax, as the heptapeptide ACTH(4-7)-Pro-Gly-Pro, and under various alphanumeric laboratory codes used by individual suppliers. These names refer to the same sequence but may imply different salt forms, purity grades, or counter-ions. Peptide databases usually list the free base mass, while product descriptions sometimes report acetate or trifluoroacetate salts with a different formula weight. Because naming conventions for research peptides are not standardised across vendors, checking the declared sequence and measured mass is more reliable than relying on a trade name alone.
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。
Semax is a synthetic heptapeptide with the sequence Met-Glu-His-Phe-Pro-Gly-Pro. Its chain combines the first seven residues of corticotropin with a C-terminal proline-glycine-proline extension, a modification intended to slow enzymatic breakdown. The free peptide has a molecular mass near 813.9 daltons. It belongs to the class of ACTH-derived fragments studied for central nervous system activity rather than for adrenal steroid stimulation. This structural relationship to a natural hormone fragment is the usual starting point for describing the compound in the literature.
Development took place during the 1980s at institutes of the Russian Academy of Sciences, where peptide fragments of ACTH were screened for cognitive and neuroprotective effects. The compound received regulatory approval in Russia as a nasal preparation, marketed for conditions such as ischemic stroke, transient ischemic attacks, and optic nerve disorders. Registration in other countries has not followed. Most published clinical reports originate from a small number of Russian research groups, and independent replication outside that setting remains limited. The regulatory status therefore differs sharply between Russia and the rest of the world.
Laboratory work points toward modulation of neurotrophic signaling, particularly expression of brain-derived neurotrophic factor and nerve growth factor in hippocampal tissue. Studies also describe effects on monoamine turnover, inflammatory mediators, and oxidative markers. These observations come mainly from animal models and cultured cells, so the causal chain in humans is not firmly established. Whether the reported molecular changes translate into measurable clinical benefit is an open question. Reviews generally present the mechanism as plausible rather than demonstrated.
== External links == Anatomy figure: 20:06-01 at Human Anatomy Online, SUNY Downstate Medical Center - "The conduction system of the heart." Diagram at gru.net thoraxlesson4 at The Anatomy Lesson by Wesley Norman (Georgetown University) (thoraxheartinternalner) https://web.archive.org/web/20070929080346/http://www.healthyheart.nhs.uk/heart_works/heart03.shtml
== External links == Food for Thought: Mushrooming Concerns "Science News Online" article on T. flavovirens (T. equestre). Tricholoma equestre poisoning "About Health Canada" article on Tricholoma equestre poisoning. Recent Poisonings from Edible Mushrooms! A report on a few new kinds of mushroom poisoning. Riddarmusseronen kan vara giftig Swedish article on T. flavovirens and its toxicity. Matportalen: Matsoppen som ble giftsopp Norwegian article on T. equestre.
The amendments required union leaders to file affidavits with the United States Department of Labor declaring that they were not supporters of the Communist Party and had no relationship with any organization seeking the "overthrow of the United States government by force or by any illegal or unconstitutional means" as a condition to participating in NLRB proceedings. Just over a year after Taft–Hartley passed, 81,000 union officers from nearly 120 unions had filed the required affidavits. This provision was at first upheld in the 1950 Supreme Court decision American Communications Ass'n v. Douds, but in 1965 in United States v. Brown, the Supreme Court held that this provision was an unconstitutional bill of attainder.
=== Heat shock response === Another aspect is the similarity of arsenic effects to the heat shock response. Short-term arsenic exposure has effects on signal transduction inducing heat shock proteins with masses of 27, 60, 70, 72, 90, and 110 kDa as well as metallothionein, ubiquitin, mitogen-activated [MAP] kinases, extracellular regulated kinase [ERK], c-jun terminal kinases [JNK] and p38. Via JNK and p38 it activates c-fos, c-jun and egr-1 which are usually activated by growth factors and cytokines. The effects are largely dependent on the dosing regime and may be as well inversed. As shown by some experiments reviewed by Del Razo (2001), reactive oxygen species induced by low levels of inorganic arsenic increase the transcription and the activity of the activator protein 1 (AP-1) and the nuclear factor-κB (NF-κB) (maybe enhanced by elevated MAPK levels), which results in c-fos/c-jun activation, over-secretion of pro-inflammatory and growth promoting cytokines stimulating cell proliferation. Germolec et al. (1996) found an increased cytokine expression and cell proliferation in skin biopsies from individuals chronically exposed to arsenic-contaminated drinking water. Increased AP-1 and NF-κB obviously also result in an up-regulation of mdm2 protein, which decreases p53 protein levels. Thus, taking into account p53's function, a lack of it could cause a faster accumulation of mutations contributing to carcinogenesis. However, high levels of inorganic arsenic inhibit NF-κB activation and cell proliferation. An experiment of Hu et al.
Sources: en.wikipedia.org
== Evolutionary history == It was found that pyruvate dehydrogenase enzyme found in the mitochondria of eukaryotic cells closely resembles an enzyme from Geobacillus stearothermophilus, which is a species of gram-positive bacteria. Despite similarities of the pyruvate dehydrogenase complex with gram-positive bacteria, there is little resemblance with those of gram-negative bacteria. Similarities of the quaternary structures between pyruvate dehydrogenase and enzymes in gram-positive bacteria point to a shared evolutionary history which is distinctive from the evolutionary history of corresponding enzymes found in gram-negative bacteria. Through an endosymbiotic event, pyruvate dehydrogenase found in the eukaryotic mitochondria points to ancestral linkages dating back to gram-positive bacteria. Pyruvate dehydrogenase complexes share many similarities with branched chain 2-oxoacid dehydrogenase (BCOADH), particularly in their substrate specificity for alpha-keto acids. Specifically, BCOADH catalyzes the degradation of amino acids and these enzymes would have been prevalent during the periods on prehistoric Earth dominated by rich amino acid environments. The E2 subunit from pyruvate dehydrogenase evolved from the E2 gene found in BCOADH while both enzymes contain identical E3 subunits due to the presence of only one E3 gene. Since the E1 subunits have a distinctive specificity for particular substrates, the E1 subunits of pyruvate dehydrogenase and BCOADH vary but share genetic similarities.
DNA gel electrophoresis is usually performed for analytical purposes, often after amplification of DNA via polymerase chain reaction (PCR), but may be used as a preparative technique for other methods such as mass spectrometry, RFLP, PCR, cloning, DNA sequencing, or Southern blotting for further characterization.
==== Physical gels ==== In physical gels unlike covalently linked gels the polymers chains are not covalently linked together. That means that the gel could re-dissolve in a good solvent under some conditions. Thermoresponsive physical gels, also sometimes called thermoresponsive injectable gels have been used in Tissue Engineering. This involves mixing at room temperature the thermoresponsive polymer in solution with the cells and then inject the solution to the body. Due to the temperature increase (to body temperature) the polymer creates a physical gel. Within this physical gel the cells are encapsulated. Tailoring the temperature that the polymer solution gels can be challenging because this depend by many factors like the polymer composition, architecture as well as the molar mass.
Sources: en.wikipedia.org
The CDU/CSU (Union) foreign policy spokesperson Jürgen Hardt described the end of Maduro's rule as a hopeful signal for Venezuela. The Bündnis 90/Greens co-leader Franziska Brantner called the U.S. strike a violation of international law that the German government must clearly acknowledge. The Left party leader accused U.S. President Trump of state terrorism. The AfD foreign policy spokesperson Markus Frohnmaier emphasized the principle of non-intervention while awaiting the U.S. justification for the strike.
vasoconstriction temporary blockage of a hole in a damaged blood vessel by a platelet plug blood coagulation (formation of fibrin clots) Coagulation, the changing of blood from a liquid to a gel which forms the fibrin clots, is essential to hemostasis. Intact blood vessels moderate blood's tendency to form clots. The endothelial cells of intact vessels prevent blood clotting with a heparin-like molecule and thrombomodulin, and prevent platelet aggregation with nitric oxide and prostacyclin. When endothelium of a blood vessel is damaged, the endothelial cells stop secretion of coagulation and aggregation inhibitors and instead secrete von Willebrand factor, which initiates the maintenance of hemostasis after injury. These processes seal the injury or hole until tissues are healed.
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Sources: en.wikipedia.org
Dry powder is usually kept at about -20 degrees Celsius for long-term storage and at 2 to 8 degrees Celsius for short working periods. Containers should stay sealed and protected from light and moisture to limit degradation.
Oxidation of the methionine residue to the sulfoxide is a frequently reported change, and it usually appears as an earlier-eluting peak in reversed-phase chromatography. Backbone hydrolysis products can also accumulate in aqueous solution.
Liquid chromatography coupled with mass spectrometry is the usual approach, because the observed molecular ion can be compared with a calculated mass of about 813.9 Da. Retention time alone does not establish identity.
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.