The short version of reversed-phase HPLC fits in a sentence. The long version — which is the one that helps — is below.
This page was last updated on 2025-12-19 and is reviewed periodically as new material appears.
Claims about enhanced focus, memory, or mood in healthy people rest mostly on anecdotal reports and community discussion rather than on controlled data. It remains unclear whether any cognitive benefit observed in patients recovering from brain injury would extend to uninjured users. Dose-response relationships, long-term safety, and interactions with other drugs are not well characterized in the peer-reviewed literature. Questions about optimal route of administration and treatment duration likewise remain open.
Semax binds to melanocortin receptors and is thought to influence neuronal survival and plasticity rather than to act through the adrenal axis. Laboratory work has shown increased expression of brain-derived neurotrophic factor and nerve growth factor in treated tissue. Changes in c-Fos, a marker of neuronal activation, have also been reported. Because the peptide is rapidly degraded by peptidases, its effects are generally attributed to downstream signaling cascades rather than to sustained receptor occupancy.
Published studies are dominated by animal models of stroke, ischemia, and cognitive impairment, with a smaller number of human trials conducted in Russia. Many of the human reports are small, single-center, and published in Russian-language journals, which limits independent scrutiny. Outcome measures vary between studies and often rely on clinician-rated scales rather than objective biomarkers. Systematic reviews have noted the methodological weaknesses and called for larger, preregistered trials before firm conclusions can be drawn.
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。
| Property | Value | Notes |
|---|---|---|
| Appearance | White lyophilized powder | Typical for synthetic peptides |
| Solubility | Freely soluble in water | Also soluble in saline |
| Storage temperature | -20 C or below | Protect from repeated freeze-thaw |
| Analytical method | Reverse-phase HPLC | Confirms purity and identity |
| Common synonym | ACTH(4-10) analog | Reflects structural origin |
Quality documentation for research-grade peptide usually includes a certificate of analysis stating purity, identity, and residual counterion content. Batch-to-batch variation in purity and salt form is a recognized issue, and comparisons across suppliers require attention to the exact counterion, for example acetate versus trifluoroacetate. Sequence verification by tandem mass spectrometry provides stronger evidence than a single mass measurement. For any study reporting biological results, the analytical method and the measured purity should be stated explicitly. Independent verification of supplier claims is considered good practice.
Semax is supplied as a lyophilized powder that appears white to off-white. It dissolves readily in water, phosphate-buffered saline, and other aqueous media, which simplifies preparation of working solutions for laboratory use. The nasal products registered in Russia are dilute aqueous solutions, typically around 0.1 percent peptide by weight. Organic solvents are rarely necessary and can complicate handling. Because the peptide is hygroscopic, weighing should be performed quickly and with minimal exposure to ambient humidity.
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.
On 15 April 1944, VIII Fighter Command began "Operation Jackpot", attacks on Luftwaffe fighter airfields. As the efficacy of these missions increased, the number of fighters at the German airbases fell to the point where they were no longer considered worthwhile targets. On 21 May, targets were expanded to include railways, locomotives, and other rolling stock used by the Germans to transport materiel and troops, in missions dubbed "Chattanooga". The P-51 excelled at this mission, although losses were much higher on strafing missions than in air-to-air combat, partially because the Mustang's Merlin engine, being liquid cooled, was vulnerable to radiator and coolant line damage from small-arms gunfire. On the other hand, the Mustang's stablemate, the Republic P-47 Thunderbolt, being powered by an air-cooled radial engine, could usually shrug off small-arms fire, and thus was regularly tasked with ground-strafing missions.
In the classical pathway, C1 complex recognizes two IgGs or one pentamer IgM, forming an antigen-antibody complex. For the lectin pathway, mannose-binding lectin (MBL) and their associated serine proteins (MASPs), recognize carbohydrates on pathogens, which initiates the C3 convertase C4b2b. The alternative pathway is different due to its spontaneous activation in fluid phase by hydrolysis of C3 to C3(H2O). C3(H2O) can bind to Factor B, which can then be cleaved by the serum protease Factor D, resulting in formation of C3(H2O)Bb. C3(H2O)Bb can cleave additional C3 molecules, creating C3b and C3a.
He considered the West Midlands dialect of Middle English to be his own "native language", and, as he wrote to W. H. Auden in 1955, "I am a West-midlander by blood (and took to early west-midland Middle English as a known tongue as soon as I set eyes on it)."
Max Vasmer's etymological dictionary traces the name to the Tatar Turkic word kazak, kozak, in which cosac meant 'free man' but also 'conqueror'. The ethnonym Kazakh is from the same Turkic root. In written sources, the name is first attested in the Codex Cumanicus from the 13th century. Larysa Pritsak (2024) grouped the earliest references of the word Cossack(s) into three groups:
Sources: en.wikipedia.org
=== Targeted delivery vehicles === Specially targeted delivery vehicles aim to increase effective levels of chemotherapy for tumor cells while reducing effective levels for other cells. This should result in an increased tumor kill or reduced toxicity or both.
== Mechanisms == VIP binds to both VPAC1 and VPAC2 receptors. When VIP binds to VPAC2 receptors, a G-alpha-mediated signaling cascade is triggered. In a number of systems, VIP binding activates adenyl cyclase activity leading to increases in cAMP concentration and PKA activity. The PKA then activates other intracellular signaling pathways like the phosphorylation of CREB and other transcriptional factors. The mPer1 and mPer2 promoters have CRE domains and thus provides the mechanism for VIP to regulate the molecular clock itself. Then it will activate gene expression pathways such as Per1 and Per2 in circadian rhythm. In addition, GABA levels are connected to VIP in that they are co-released. Sparse GABAergic connections are thought to decrease synchronized firing. While GABA controls the amplitude of SCN neuronal rhythms, it is not critical for maintaining synchrony. However, if GABA release is dynamic, it may mask or amplify synchronizing effects of VIP inappropriately. Circadian time is likely to affect the synapses rather than the organization of VIP circuits.
== Side effects == Common adverse effects associated with the use of codeine include drowsiness and constipation. Less common are itching, nausea, vomiting, dry mouth, miosis, orthostatic hypotension, urinary retention, euphoria, and dysphoria. Rare adverse effects include anaphylaxis, seizure, acute pancreatitis, and respiratory depression. As with all opiates, long-term effects can vary, but can include diminished libido, apathy, and memory loss. Some people may have allergic reactions to codeine, such as the swelling of the skin and rashes. In August 2012, the United States Food and Drug Administration issued a warning about deaths in pediatric patients less than 6 years old after ingesting "normal" doses of paracetamol with codeine after tonsillectomy; this warning was upgraded to a black box warning in February 2013.
Sources: en.wikipedia.org
It is associated with the melanocortin receptor family, particularly subtypes found in the central nervous system. This interaction is separate from the adrenal pathway activated by full-length ACTH.
Peptidases degrade the compound within minutes in circulation. This short half-life is one reason nasal delivery is used, placing the substance close to the olfactory and trigeminal pathways.
No large multicenter trials have been published in English-language journals. The existing human evidence consists mainly of smaller studies conducted in Russia, which limits generalization.
不存在。它是依据 ACTH 的一段序列人工设计的分子，天然蛋白质中找不到与之完全相同的七肽。名称属于研究代号，而非天然物质名。