intranasal delivery comes up often in conversation and rarely with the context attached. Here we lay out the basics in order, then work through the practical considerations.
Updated 2025-11-20. Numbers and descriptions here follow the published literature rather than marketing material.
Regulatory status varies sharply by country. Semax is registered for medical use in Russia, where it appears in formularies as a nasal solution, and it also holds registration in a small number of neighbouring states. It has no approval from the United States Food and Drug Administration or the European Medicines Agency, and it is not a scheduled controlled substance in most jurisdictions. Elsewhere it circulates mainly as laboratory material, so purity documentation comes from suppliers rather than from a national pharmacopoeia.
Semax is a synthetic peptide created in the Soviet Union during the early 1980s by researchers working in Moscow. It was built from the short adrenocorticotropic hormone fragment known as ACTH(4-10), and the chain was then extended with three additional amino acids. The resulting molecule was named semax and entered clinical use in Russia in 1994. It is generally described as a nootropic and neuroprotective agent rather than as a hormone analogue.
The parent fragment ACTH(4-10) carries the sequence Met-Glu-His-Phe-Arg-Trp-Gly. Semax replaces the arginine and tryptophan positions with a proline-glycine-proline tail, giving Met-Glu-His-Phe-Pro-Gly-Pro. That change removes residues associated with adrenal stimulation, so the peptide does not drive cortisol release the way full ACTH does. This distinction shapes how the compound is grouped in the literature, where it sits with neuropeptides and peptide neuromodulators rather than with corticosteroids.
常规纯度与身份确认依赖反相高效液相色谱，并辅以质谱测定分子量。氨基酸组成分析可用于验证序列构成，肽图分析则能进一步定位修饰或降解产物。杂质谱通常关注缺失序列肽、截短片段和氧化产物。不同方法的检出限并不相同，因此各实验室报告的纯度数值不宜直接横向比较。
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。
| Property | Value | Notes |
|---|---|---|
| Chemical class | Synthetic heptapeptide | Analogue of the ACTH(4-10) fragment |
| Amino acid sequence | Met-Glu-His-Phe-Pro-Gly-Pro | Single-letter form MEHFPGP |
| Molecular formula | C37H51N9O10S | Free peptide, nominal mass near 814 Da |
| First registration | 1994, Russia | Nasal formulation for neurological indications |
| Typical purity grade | 95% or higher by HPLC | Research material; higher grades used as reference standards |
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。
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。
Lyophilized material is chemically stable for extended periods when kept dry, cold, and protected from light. The powder is hygroscopic, so vials should be warmed to room temperature before opening to reduce condensation on the contents. Once dissolved, the peptide is far less stable because peptide bonds are susceptible to hydrolysis and the methionine residue can oxidize. Solutions are typically aliquoted and held at 2-8 °C for short intervals or frozen for longer ones, and repeated freeze-thaw cycles should be avoided.
Routine characterization relies on reversed-phase high-performance liquid chromatography to establish purity and on mass spectrometry to confirm molecular identity. Electrospray ionization and matrix-assisted laser desorption ionization are both used for mass verification. Amino acid analysis and peptide mapping can detect sequence errors. Common impurities include truncated sequences, methionine sulfoxide formed by oxidation, and deamidated products. Chromatograms are usually recorded near 214 nm, where the peptide backbone absorbs, and purity is reported as the percentage area of the principal peak.
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.
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.
Circulation time for the peptide is short because peptidases cleave it readily. The Pro-Gly-Pro tail is thought to slow breakdown compared with the bare ACTH fragment, but the gain appears modest. Absorption after intranasal dosing is limited, and only a fraction of a dose is expected to reach the central nervous system. Laboratory concentrations therefore sit well above levels achieved systemically, a gap that complicates translation from bench findings to clinical claims.
The mechanisms attributed to semax are inferred from animal and cell studies rather than traced to one confirmed target. The most frequently cited pathway involves increased expression of brain-derived neurotrophic factor and nerve growth factor in hippocampal and cortical tissue. Some work points to engagement of melanocortin receptors, particularly MC4, which the parent ACTH fragment can activate. Effects on dopaminergic and serotonergic signalling have also been reported. No single account explains all observed results, and the relative weight of each pathway remains unsettled.
Published studies examine a fairly narrow set of endpoints. Rodent experiments commonly measure maze learning, infarct volume after induced ischemia, and tissue levels of neurotrophic factors. Clinical reports from Russian centres describe attention, memory and recovery scores in patients after stroke or transient ischemic attack. Most of those human studies are small and few have been repeated by independent groups. Outcome measures differ between studies, which limits direct comparison.
== Laboratory scale == Centrifugal partition chromatography has been extensively used for isolation and purification of natural products for 40 years. Due to the ability to get very high selectivity, and the ability to tolerate samples containing particulated matter, it is possible to work with direct extracts of biomass, opposed to traditional liquid chromatography, where impurities degrade the solid stationary phase so that separation become impossible. There are numerous laboratory scale centrifugal partition chromatography manufacturers around the world, like Gilson (Armen Instrument), Kromaton (Rousselet Robatel), and AECS-QUIKPREP. These instruments operate at flow rates of 1–500 mL/min. with stationary phase retentions of 40–80%. With the new rotor system created after 2022, LiLiChro was able to create a truly analytical instrument (miniLiLi) with a rotor internal volume of only 34ml, which means it can operate at a flow rate of 1ml/min. On the other hand, both the miniLiLi and the 140ml midiLiLi can operate with 90+% stationary phase retention.
Many items denoting 'rank and prestige' were deposited in the water surrounding Flag Fen, including swords, spearheads, 'gold earrings, tiny pins and brooches'. Archaeologist Francis Pryor, who discovered the site in 1982, suggests that 'settlers often vied for social status by showing they could afford to discard valuable possessions'. There is also evidence of intentional destruction before placement, e.g. daggers broken in half placed on top of each other. Other finds included small, polished, white stones of a type not known in the area, indicating that they had been intentionally collected and transported to and placed at the site. Other artefacts found were animal bones, including horse mandibles. Horses were very valuable to the prehistoric people, since they provided a means of transport and could supplement or replace man-power. For example, they could be used to carry or pull timbers on sledges over long distances. Significance is also drawn from the discovery of the ritual deposits within thirty metres of the timber post line, and only on its southern boundary. The amount, type, and placement of deposits, which continued for more than 1,200 years, support the theory that 'at least one facet of the site' was a role as a 'religious monument'. On Northey Island many round barrows contemporary with Flag Fen were found. These seemed to be constructed over the dwellings of 'chiefs'. Mike Parker Pearson refers to this as the "Land of the Dead". There is also evidence of farming, including sheep remains, contemporary with the site.
=== Applications for oceanography === Tracers are also used extensively in oceanography to study a wide array of processes. The isotopes used are typically naturally occurring with well-established sources and rates of formation and decay. However, anthropogenic isotopes may also be used with great success. The researchers measure the isotopic ratios at different locations and times to infer information about the physical processes of the ocean.
=== Lily Tao === Lily Tao (played by an uncredited child actress in series 1, Neve Bonner in series 2-3, and Serrana Su-Ling Bliss in series 4) is one of Eric and Candice's daughters, alongside her twin sister Lara. In series 1, Harper spots Eric playing with his daughters in a grocery store after being suspended from Pierpoint. In series 2, Eric returns home from a trip to New York to kiss his children goodnight, having secretly cheated on their mother with his ex-girlfriend Holly during the trip. In series 3, Eric, divorced from Candice, brings his daughters to Pierpoint on the day of the tumultuous IPO of green-energy company Lumi. In series 4, Lily is older and attending private school in England, while Eric is retired and living in the United States, estranged from his family. His family office, LilyLara, is named after his daughters. Eric returns to London to partner with Harper on a short-only hedge fund, SternTao, and allows Lily to visit the hotel serving as their office, blurring the work-life boundary Harper strives to maintain with Eric. Eric later learns Lily has been expelled from school for running a catfishing scheme on another student, and reflects on how his daughter has inherited his own cruelty, while lamenting his own inability to properly love his children. He comforts Lily and allows her and Candice to stay in his suite, but visits a prostitute that same night.
Many of the best known Guinness television advertisements of the 1970s and 1980s were created by British director, Len Fulford. In 1983, a conscious marketing decision was made to turn Guinness into a "cult" beer in the UK, amidst declining sales. The move halted the sales decline. The Guardian described the management of the brand: "They've spent years now building a brand that's in complete opposition to cheap lagers, session drinking and crowds of young men boozing in bars. They've worked very hard to help Guinness drinkers picture themselves as twinkly-eyed, Byronic bar-room intellectuals, sitting quietly with a pint and dreaming of poetry and impossibly lovely redheads running barefoot across the peat. You have a pint or two of Guinness with a slim volume of Yeats, not eight mates and a 19-pint bender which ends in tattoos, A&E [the ED] and herpes from a hen party." In the late 1980s and early 1990s, in the UK, there was a series of "darkly" humorous adverts, featuring actor Rutger Hauer, with the theme "Pure Genius", extolling its qualities in brewing and target market. The 1994–1995 Anticipation TV ad, featuring actor Joe McKinney dancing to "Guaglione" by Pérez Prado while his pint settled, led to the song being re-released and becoming a number one hit in Ireland and reaching number two in the UK. The length of time it takes to pour a proper pint of stout was also the focus of the "Good things come to those who wait" campaign in the UK in the later 1990s.
Sources: en.wikipedia.org
Kleiner believes the vessel contains technology capable of combating the Combine, but Eli argues the vessel should be destroyed. They agree that Alyx and Gordon should travel to the ship and locate Mossman. Alyx unconsciously delivers the G-Man's message to her father, troubling him. Gordon learns from Eli that the G-Man provided the test sample which caused the Black Mesa Incident, warning Eli with the same message as Gordon entered the test chamber. He promises to explain more after the portal is closed. While the scientists prepare the launch, the Combine attack White Forest again. Gordon defeats them using explosive weaponry created by Magnusson. The scientists launch the rocket and close the portal, trapping all remaining Combine forces on Earth. As Alyx and Freeman prepare to leave for the Borealis, Eli warns Gordon about the ship's "cargo". The trio head to a hangar to board a helicopter, but two Combine Advisors appear and restrain them. Eli is killed by an Advisor before Dog can chase the Advisors away. Alyx, sobbing, clutches her father's body.
=== Muscle mass === Researchers are still debating whether the more noticeable muscles are larger in size as well. It should be clarified, though, that muscle mass is not the same as muscle strength. Some say that human growth hormone will build muscle mass through raised insulin-like growth factors levels leading to heightened protein synthesis without any side effects while other researchers argue that there have been no such findings on young healthy adults. The second argument is more supported by research discoveries that HGH affects muscle protein synthesis no differently than a placebo does.
=== Spectrum of activity === Like other third-generation cephalosporins, ceftriaxone is active against Citrobacter spp., Serratia marcescens, and beta-lactamase-producing strains of Haemophilus and Neisseria. However, unlike ceftazidime and cefoperazone, ceftriaxone does not have useful activity against Pseudomonas aeruginosa. It is generally not active against Enterobacter species, and its use should be avoided in the treatment of Enterobacter infections, even if the isolate appears susceptible, because of the emergence of resistance. Some organisms, such as Citrobacter, Providencia, and Serratia, have the ability to become resistant through the development of cephalosporinases (enzymes that hydrolyze cephalosporins and render them inactive). Although not being used as first line therapy against Staphylococcus aureus, ceftriaxone retains activity against isolates of methicillin-susceptible S. aureus and is used in clinic for infections sustained by this bacterium. In this case the dose should be doubled (e.g. 2 g intravenously every 12 hours).
== Inhibitors == Glycogen synthase kinase inhibitors are different chemotypes and have variable mechanisms of action; they may be cations, from natural sources, synthetic ATP and non-ATP competitive inhibitors and substrate-competitive inhibitors. GSK3 is a bi-lobar architecture with N-terminal and C-terminal, the N-terminal is responsible for ATP binding and C-terminal which is called as activation loop mediates the kinase activity, Tyrosine located at the C-terminal it essential for full GSK3 activity.
Sources: en.wikipedia.org
Registered medical products are most often 0.1% nasal drops. Research suppliers ship lyophilized powder, usually in milligram quantities, which is dissolved before use. The active peptide is the same in both cases; presentation and excipients differ.
No. The peptide is synthetic, although it is modelled on a fragment of a naturally occurring hormone. ACTH(4-10) is generated when ACTH is cleaved, but the Pro-Gly-Pro extension is not a known endogenous sequence. It is therefore a designed analogue rather than a natural metabolite.
The label reflects reported effects on attention, memory and recovery after neurological injury in regional clinical reports. Those reports are mostly small and have not been widely replicated outside the region. The classification is descriptive and does not imply a single defined mechanism.
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。