A practical reference on reversed-phase HPLC: what it is, how it behaves, what the literature reports, and where the honest uncertainties sit.
This page was last updated on 2025-10-28 and is reviewed periodically as new material appears.
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.
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.
Identity and purity are commonly assessed by reversed-phase high-performance liquid chromatography, with ultraviolet detection near 214 nanometers for the peptide backbone. Mass spectrometry, either electrospray or matrix-assisted laser desorption, confirms molecular mass and detects truncation or modification products. Amino acid analysis can verify composition. Because the sequence contains no strongly absorbing aromatic residue apart from phenylalanine, detection wavelengths are chosen carefully. Purity values above 95 percent are typical for research-grade material.
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.
| 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 |
Clinical reports describe use in ischaemic stroke, transient ischaemic attack, optic nerve conditions, and cognitive complaints, but most of these studies are small and were conducted in a single region. Systematic reviews have generally described the evidence base as limited in size and variable in methodological quality. Randomised controlled data suitable for international regulatory assessment are scarce. As a result, major treatment guidelines outside Russia do not include the peptide, and interest in it remains largely research-driven rather than routine clinical.
Semax is a synthetic heptapeptide with the sequence Met-Glu-His-Phe-Pro-Gly-Pro. It is described in the literature as an analogue of the ACTH(4–10) fragment, a short N-terminal portion of adrenocorticotropic hormone that retains some neurotropic activity without the full hormonal effects of the parent peptide. The molecule carries a methionine residue at the N-terminus and two proline residues near the C-terminus, features that shape both its interactions with receptor systems and its chemical stability. The free peptide corresponds to the formula C37H51N9O10S and a molecular mass near 813.9 Da.
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.
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.
Material sold for laboratory use varies widely in stated purity and documentation. A certificate of analysis should list the analytical method, the column and detector used, and the observed purity value. Independent verification by an outside laboratory is the practical way to confirm identity when documentation is absent or internally inconsistent. Regulatory status differs by country, and a product legal in one jurisdiction may be unapproved or controlled in another.
Identity and purity of semax are established with reversed-phase high-performance liquid chromatography coupled to ultraviolet detection, usually at 214 nanometres. Mass spectrometry, most often electrospray ionisation in positive mode, confirms the molecular mass and reveals truncated sequences. Amino acid analysis and peptide mapping after enzymatic digestion provide additional structural confirmation. Laboratories typically report purity as the percentage area of the main peak, a figure that does not capture isomeric or oxidised variants unless the method resolves them.
The peptide is prone to several degradation pathways. Oxidation of the methionine residue produces a sulfoxide that elutes close to the parent peak in many chromatographic systems. Hydrolysis of peptide bonds and deamidation of susceptible residues in related sequences also reduce purity over time. Lyophilised material kept dry at minus twenty degrees Celsius and shielded from light is the most stable form commonly described in laboratory practice.
==== Isomerization ==== The isomerization of uridine to pseudouridine is the second most common rRNA modification. These pseudouridines are also introduced by the same classes of snoRNPs that participate in methylation. Pseudouridine synthases are the major participating enzymes in the reaction. The H/ACA box snoRNPs introduce guide sequences that are about 14-15 nucleotides long. Pseudouridylation is triggered in numerous places of rRNAs at once to preserve the thermal stability of RNA. Pseudouridine allows for increased hydrogen bonding and alters translation in rRNA and tRNA. It alters translation by increasing the affinity of the ribosome subunit to specific mRNAs.
== Overdose == Cases of overdose are quite rare. In the event of an overdose people may experience severe hypotension, electrolyte imbalances or abnormal heart rhythms. People are advised to contact emergency services or a poison control centre and are treated based on symptoms.
27 March – Humza Yousaf is elected as the Leader of the Scottish National Party and subsequently, First Minister of Scotland. He is the youngest holder of the position in history at just 37 years of age upon entry to office, the first from an ethnic minority background, the first Muslim to hold the office and the first First Minister with facial hair. 28 March Humza Yousaf is confirmed as Scotland's First Minister by a vote in the Scottish Parliament. Kate Forbes is to leave the Scottish Government after turning down a position in the Yousaf ministry. 29 March – Humza Yousaf is sworn in as Scotland's First Minister at Edinburgh's Court of Session and begins naming his Cabinet. 30 March The Parliamentary Standards Committee recommends that former Scottish National Party MP Margaret Ferrier be suspended from the House of Commons for 30 days for breaching COVID-19 regulations in September 2020 when she took a train home from London following a positive COVID test. Humza Yousaf attends his first session of First Minister's Questions since his election as First Minister. The session is interrupted on several occasions by climate change protestors, forcing the Presiding Officer of the Scottish Parliament to clear the gallery of visitors.
G-protein-coupled receptor (GPCR) A large family of membrane receptors that activate intracellular signaling pathways through G-proteins. GPCRs are critical in neurotransmission, hormone signaling, and sensory perception. Granule cell A small neuron found in the cerebellum, olfactory bulb, and dentate gyrus of the hippocampus. Granule cells play important roles in sensory and motor information processing. Granulomatosis with polyangiitis An autoimmune disease that can affect the central nervous system, sometimes causing neuropathy, headaches, or stroke-like symptoms due to vascular inflammation. Grasp reflex A primitive reflex seen in infants where touching the palm induces the hand to close. Persistence in adults may indicate frontal lobe damage. Gray matter Brain tissue composed primarily of neuronal cell bodies, dendrites, and unmyelinated axons. It is responsible for information processing and synaptic transmission. Growth cone A dynamic, motile structure at the tip of a developing axon or dendrite that guides neuronal growth by sensing molecular cues in the environment. Growth factor A naturally occurring protein that stimulates cell growth, differentiation, and survival. Examples include BDNF, NGF, and EGF in neural development and repair. Gustatory cortex The brain area responsible for processing taste information, primarily located in the insular and frontal opercular regions. Gyri (singular gyrus) The raised ridges or folds of the cerebral cortex. They increase the brain’s surface area and are separated by sulci (grooves).
Sources: en.wikipedia.org
=== Pharmacokinetics === It is metabolized mostly by esterases, and almost completely. The metabolites are excreted in urine. Mebeverine exists in two enantiomeric forms. The commercially available product is a racemic mixture of them. A study in rats indicates that the two have different pharmacokinetic profiles. The drug contains the psychoactive drugs moiety such as para-methoxy-N-ethylamphetamine (PMEA) and para-methoxyamphetamine (PMA) within its chemical structure and can form these drugs as minor active metabolites. This can result in false positives for "ecstasy" on drug tests.
== Aquaculture == Farming of Atlantic cod has received a significant amount of interest due to the overall trend of increasing cod prices alongside reduced wild catches. However, progress in creating large scale farming of cod has been slow, mainly due to bottlenecks in the larval production stage, where survival and growth are often unpredictable. It has been suggested that this bottleneck may be overcome by ensuring cod larvae are fed diets with similar nutritional content as the copepods they feed on in the wild Recent examples have shown that increasing dietary levels of minerals such as selenium, iodine and zinc may improve survival and/or biomarkers for health in aquaculture reared cod larvae.
Born in Belleville, Ontario, he enrolled at Trinity College at the University of Toronto at the age of 15, and studied physiology and biochemistry. He obtained a Ph.D. in biochemistry from the same university in 1916.
25298Cf + 115B → 263103Lr* → 258103Lr + 5 10n The first work at Dubna on element 103 came in 1965, when they reported to have made 256Lr in 1965 by bombarding 243Am with 18O, identifying it indirectly from its granddaughter fermium-252. The half-life they reported was somewhat too high, possibly due to background events. Later 1967 work on the same reaction identified two decay energies in the ranges 8.35–8.50 MeV and 8.50–8.60 MeV: these were assigned to 256Lr and 257Lr. Despite repeat attempts, they were unable to confirm assignment of an alpha emitter with a half-life of 8 seconds to 257Lr. The Russians proposed the name "rutherfordium" for the new element in 1967; this name was later proposed by Berkeley for element 104.
== Uses == Alpha emitters are used in smoke detectors. The alpha particles ionize air in an open ion chamber and a small current flows through the ionized air. Smoke particles from the fire that enter the chamber reduce the current, triggering the smoke detector's alarm. Radium-223 is also an alpha emitter. Its use has been trialed with successful results in treating bone metastasis resulting from Castration-resistant metastatic prostate cancer. Alpha decay can provide a safe power source for radioisotope thermoelectric generators used for space probes and were used for artificial heart pacemakers. Alpha decay is much more easily shielded against than other forms of radioactive decay. Static eliminators typically use polonium-210, an alpha emitter, to ionize the air, allowing the "static cling" to dissipate more rapidly.
Sources: en.wikipedia.org
Amid decolonisation and the Wind of Change, the Federation failed to become a Commonwealth realm and collapsed in 1963. Two years later, following prolonged dispute with Britain over the terms for full sovereignty, the mostly white government in Southern Rhodesia (or Rhodesia, following Northern Rhodesia's independence as Zambia) issued a Unilateral Declaration of Independence (UDI). The Rhodesian government, which had in it World War II veterans including the Prime Minister Ian Smith, attempted to emphasise Rhodesians' prior war record on Britain's behalf by declaring independence on Armistice Day, 11 November, at 11:00 local time. As part of its subsequent isolation of Rhodesia, the UK government banned the post-UDI authorities from taking part in the annual Armistice Day service at the Cenotaph in London. Smith's government organised its own Rhodesian wreath-laying ceremony there. Veterans of World War II and Malaya held many key positions in the Rhodesian Security Forces during the Bush War of the 1970s. After the country's reconstitution and recognised independence as Zimbabwe in 1980, Robert Mugabe's administration pulled down many monuments and plaques making reference to the dead of the First and Second World Wars, perceiving them as reminders of white minority rule and colonialism that went against what the modern state stood for. This view was partly rooted in the association of these memorials with those commemorating the British South Africa Company's dead of the Matabele Wars, as well as those memorialising Rhodesian servicemen killed during the Bush War.
Neuroimaging studies have observed that fibromyalgia patients have increased grey matter in the right postcentral gyrus and left angular gyrus, and decreased grey matter in the right cingulate gyrus, right paracingulate gyrus, left cerebellum, and left gyrus rectus. These regions are associated with affective and cognitive functions and with motor adaptations to pain processing. Other studies have documented decreased grey matter of the default mode network in people with fibromyalgia. These deficits are associated with pain processing. According to a 2024 review article the evidence for central sensitization as an underlying mechanism in chronic pain conditions such as fibromyalgia has significant limitations, such as failing to demonstrate causality, and the use of measures described as measuring central sensitization which do not measure it as a neurophysiological phenomenon, leading to circular reasoning.
In the BG system the pound is a basic unit from which the unit of mass (the slug) is defined by Newton's second law, whereas in the EE system the units of force and mass (the pound-force and pound-mass respectively) are defined independently through the second law using the proportionality constant gc. Kinematic viscosity has units of square feet per second (ft2/s) in both the BG and EE systems. Nonstandard units include the reyn (lbf·s/in2), a British unit of dynamic viscosity. In the automotive industry the viscosity index is used to describe the change of viscosity with temperature. The reciprocal of viscosity is fluidity, usually symbolized by
== Origin == The genetic code is a key part of the history of life. Under the RNA world hypothesis, self-replicating RNA molecules preceded significant use of proteins. Under the nucleopeptide world hypothesis, significant use of peptides preceded the genetic code and was concurrent with early life's sophisticated use of RNA. Transfer RNA molecules appear to have evolved before modern aminoacyl-tRNA synthetases. It is possible that synthetases replaced an earlier system of ribozymes (RNA enzymes), or that amino acids were recognized by unique pockets in the tertiary structure of proto-tRNAs. It is not known why the genetic code only uses L-amino acids and not D-amino acids. Any evolutionary model for the code's origin must account for its robustness of encoded proteins to errors during DNA replication and during translation. Many single nucleotide errors are synonymous, and those that are not tend to cause the substitution of a biochemically similar amino acid. Even holding the structure of the code the same such that clusters of codons encode the same amino acid, which amino acids are encoded by which sets of codons is "one in a million" with respect to robustness. Biochemically similar amino acids tend to share the same middle nucleotide, while synonymous changes generally happen at the third nucleotide. Amino acids that share the same biosynthetic pathway tend to have the same first base in their codons. This could be an evolutionary relic of an early, simpler genetic code with fewer amino acids that later evolved to code a larger set of amino acids.
The series' first program War, Oil and Power was compiled and released in 1990, before the war broke out. News World Order was the title of another program in the series; it focused on the media's complicity in promoting the war, as well as Americans' reactions to the media coverage. Media watchdog group Fairness and Accuracy in Reporting (FAIR) critically analyzed media coverage during the war in various articles and books, such as the 1991 Gulf War Coverage: The Worst Censorship was at Home.
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.
Solid peptide is best kept frozen at about minus 20 degrees Celsius in a sealed container with desiccant. It should be allowed to reach room temperature before opening to prevent condensation. Repeated warming and cooling of the same vial is discouraged.