The short version of melanocortin signalling fits in a sentence. The long version — which is the one that helps — is below.
Reviewed 2025-12-12. Anything still debated is marked as such rather than presented as settled.
Identity and purity of Semax are established mainly by reversed-phase high-performance liquid chromatography coupled with mass spectrometry. The chromatographic trace gives a purity estimate as a percentage of total peak area, while electrospray or matrix-assisted laser desorption ionization confirms the molecular mass against the calculated value. Amino acid analysis and sequence-specific fragmentation provide further confirmation when a supplier's chain of custody is unclear. Vendors frequently quote a purity figure without stating the detection wavelength or the integration method, which limits how far one number can be compared with another.
Stability depends heavily on physical state. Lyophilized powder held dry, cold and dark retains its content over long periods, whereas dissolved peptide begins to change within days at room temperature. The most cited degradation route is oxidation of the methionine residue, which converts the peptide to a sulfoxide form that elutes differently on chromatography. Hydrolysis of amide bonds and adsorption onto container walls contribute smaller losses. Buffers that exclude oxygen from the headspace slow the oxidation pathway, but no single condition prevents all change indefinitely.
Practical handling follows from those properties. Bulk material is best divided into single-use portions soon after receipt, because each thaw exposes the whole container to moisture and temperature cycling. Vials should be allowed to reach room temperature before opening to prevent condensation on the powder. Low-binding plasticware reduces loss of dilute solutions, and sterile filtration is used when a preparation must remain free of microbial growth. Records of batch number, reconstitution date and storage history are what allow a later analytical result to be interpreted meaningfully.
Semax is a synthetic heptapeptide developed in the Soviet Union during the 1980s by researchers at the Institute of Molecular Genetics in Moscow. It was designed as a truncated analog of adrenocorticotropic hormone, retaining only the fragment spanning residues four through ten. Investigators sought a peptide that would preserve the cognitive effects associated with ACTH while eliminating the hormonal stimulation of the adrenal cortex. The compound entered clinical use in Russia during the following decade.
Russian regulatory authorities approved the peptide for nasal administration, and it remains listed in the national pharmacopoeia under several trade names. Documented indications include acute ischemic stroke, transient ischemic attacks, traumatic brain injury, and certain ophthalmological and neurological conditions. Physicians also prescribe it for cognitive complaints in older patients, although the evidence base for that use is thinner. Outside Russia and a few neighboring states, the substance is not an approved medicine and is sold instead as a research chemical.
| Property | Value | Notes |
|---|---|---|
| Typical purity specification | ≥ 95 % of peak area by HPLC | Some suppliers quote 98 % or higher |
| Identity confirmation | Mass spectrometry (electrospray or MALDI) | Observed mass is compared with the calculated mass |
| Common analytical method | Reversed-phase HPLC on a C18 column | Acetonitrile and water gradients with trifluoroacetic acid |
| Primary degradation route | Oxidation of the methionine residue | Yields a sulfoxide that separates cleanly on chromatography |
| Storage of dissolved material | Aliquoted and frozen at −20 °C or below | Single-use aliquots avoid repeated temperature cycling |
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 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.
The compound was developed in the 1980s at the Institute of Molecular Genetics in Moscow, where it emerged from research on short ACTH fragments and their effects on the central nervous system. Russian pharmaceutical listings describe it as a nootropic and neuroprotective agent, most often formulated as nasal drops. It is not a marketed medicine in the United States or the European Union, and no pharmacopoeial monograph covers it. Consequently, most published clinical experience with the substance originates from a small number of research centres, mainly in Russia and neighbouring countries.
Pharmacological accounts link semax to melanocortin signalling and to modulation of neurotrophic factor expression, particularly brain-derived neurotrophic factor and nerve growth factor. Much of this evidence comes from rodent studies using intranasal delivery, a route chosen because it allows peptides to reach the central nervous system with limited systemic exposure. Whether the same mechanisms operate in humans at comparable magnitude remains an open question. The precise receptor or receptors responsible for the reported behavioural and neuroprotective effects have not been conclusively identified.
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.
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 Hippocratic Oath for physicians, attributed to fifth century BC Greece, refers to the existence of "deadly drugs", and ancient Greek physicians imported drugs from Egypt and elsewhere. The pharmacopoeia De materia medica, written between 50 and 70 CE by the Greek physician Pedanius Dioscorides, was widely read for more than 1,500 years.
In spring 2026, the European Parliament and the Council of the European Union defined a relative potency factor (RPF) of 0.002 perfluorooctanoic acid (PFOA) equivalents for TFA, while a threshold of 0.0044 µg/L PFOA equivalents for the sum of 25 PFAS (now including TFA) in inland surface water was set.
Bats possess a highly adapted respiratory system to cope with the demands of powered flight. They have relatively large lungs, and many species have proportionally larger alveolar surface areas and pulmonary capillary blood volumes than other mammals. During flight, the respiratory cycle has a one-to-one relationship with the wing-beat cycle. Their mammalian lungs prevent them from flying at high altitudes. Bats can also meet oxygen demands by exchanging gas through the patagium of the wing. When the bat has its wings spread, it allows for an increase in surface area to volume ratio, 85% of the surface area being the wing. The subcutaneous vessels in the membrane lie near the surface and allow for the diffusion of oxygen and carbon dioxide. The digestive system of bats varies depending on the species of bat and its diet. Digestion is relatively quick to meet the energy demands of flight. Insectivorous bats may have certain digestive enzymes to better process insects, such as chitinase to break down their chitin exoskeleton. Vampire bats, probably due to their diet of blood, are unique among vertebrates in that they do not have the enzyme maltase, which breaks down malt sugar, in their intestinal tract. Nectivorous and frugivorous bats have more maltase and sucrase enzymes than insectivores, to cope with the higher sugar contents of their diet. The adaptations of the kidneys of bats vary with their diets. Carnivorous and vampire bats consume large amounts of protein and can output concentrated urine; their kidneys have a thin cortex and long renal papillae.
Sources: en.wikipedia.org
== Pharmacodynamics == Liraglutide is an acylated glucagon-like peptide-1 (GLP-1) receptor agonist, derived from human GLP-1-(7-37), a less common form of endogenous GLP-1. It reduces meal-related hyperglycemia (for 24 hours after administration) by increasing insulin secretion (only) when required by increasing glucose levels, delaying gastric emptying, and suppressing prandial glucagon secretion. Liraglutide leads to insulin release in pancreatic beta cells in the presence of elevated blood glucose. This insulin secretion subsides as glucose concentrations decrease and approach euglycemia (normal blood glucose level). It also decreases glucagon secretion in a glucose-dependent manner and delays gastric emptying. Unlike endogenous GLP-1, liraglutide is stable against metabolic degradation by peptidases, with a plasma half-life of 13 hours.
The reduction-oxidation sensitive green fluorescent protein (roGFP) is a green fluorescent protein engineered to be sensitive to changes in the local redox environment. roGFPs are used as redox-sensitive biosensors. In 2004, researchers in S. James Remington's lab at the University of Oregon constructed the first roGFPs by introducing two cysteines into the beta barrel structure of GFP. The resulting engineered protein could exist in two different oxidation states (reduced dithiol or oxidized disulfide), each with different fluorescent properties. Originally, members of the Remington lab published six versions of roGFP, termed roGFP1-6 (see more structural details below). Different groups of researchers introduced cysteines at different locations in the GFP molecule, generally finding that cysteines introduced at the amino acid positions 147 and 204 produced the most robust results. roGFPs are often genetically encoded into cells for in-vivo imaging of redox potential. In cells, roGFPs can generally be modified by redox enzymes such as glutaredoxin or thioredoxin. roGFP2 preferentially interacts with glutaredoxins and therefore reports the cellular glutathione redox potential. Various attempts have been made to make roGFPs that are more amenable to live-cell imaging. Most notably, substituting three positively-charged amino acids adjacent to the disulfide in roGFP1 drastically improves the response rate of roGFPs to physiologically relevant changes in redox potential.
In the mid-1930s, Pauling, strongly influenced by the biologically oriented funding priorities of the Rockefeller Foundation's Warren Weaver, decided to strike out into new areas of interest. Although Pauling's early interest had focused almost exclusively on inorganic molecular structures, he had occasionally thought about molecules of biological importance, in part because of Caltech's growing strength in biology. Pauling interacted with such great biologists as Thomas Hunt Morgan, Theodosius Dobzhanski, Calvin Bridges and Alfred Sturtevant. His early work in this area included studies of the structure of hemoglobin with his student Charles D. Coryell. He demonstrated that the hemoglobin molecule changes structure when it gains or loses an oxygen molecule. As a result of this observation, he decided to conduct a more thorough study of protein structure in general. He returned to his earlier use of X-ray diffraction analysis. But protein structures were far less amenable to this technique than the crystalline minerals of his former work. The best X-ray pictures of proteins in the 1930s had been made by the British crystallographer William Astbury, but when Pauling tried, in 1937, to account for Astbury's observations quantum mechanically, he could not. It took eleven years for Pauling to explain the problem: his mathematical analysis was correct, but Astbury's pictures were taken in such a way that the protein molecules were tilted from their expected positions.
==== Israel ==== Dunkin' Donuts Israel (Hebrew: דאנקן דונאטס) was an Israeli franchise of the chain. Dunkin' Donuts Israel opened their first location in Israel in 1996 in Tel Aviv. Their main flagship store was located in Rabin Square, with their factory in Lod. Upon opening their first location, Dunkin' was a huge hit. When the original location opened, it broke Dunkin's own sales records by selling 3 million doughnuts in the first eight months. The chain's manager was quoted saying "Israelis do not stop eating doughnuts, They buy such quantities, quantities that we would never have believed they would buy. They buy boxes of 12, eat them here, and then buy more boxes to take home." In 2001, when Dunkin' Donuts Israel decided to close, the company had accumulated a large amount of debt. When the Second Intifada broke out, Israeli tourism slowed, and Dunkin' decided to close. Approximately $2 million was invested in Dunkin' Donuts Israel when it failed. At the peak, Dunkin' Donuts had 9 branches in Israel, short of their original goal of 15, including 3 in Jerusalem.
Sources: en.wikipedia.org
By 1948, Lilly employees worked in 35 countries, most of them as sales representatives in Latin America, Asia, and Africa. After three generations of Lilly family leadership under company founder, Col. Eli Lilly, his son, Josiah K. Lilly Sr., and two grandsons, Eli Lilly Jr. and Josiah K. Lilly Jr., the company announced a reorganization in 1944 that prepared the way for future expansion and the eventual separation of company management from its ownership. In 1945, Lilly began a major expansion effort that included two manufacturing operations in Indianapolis. The company purchased the massive Curtiss-Wright propeller plant on Kentucky Avenue, west of the company's McCarty Street operation. When renovation was completed in mid-1947, the Kentucky Avenue location manufactured antibiotics and capsules and housed the company's shipping department. By 1948, Lilly employed nearly 7,000 people. After World War II, patents and research records belonging to IG Farben, which included Farbwerke Hoechst, were confiscated by the Allies. The U.S. Department of Commerce made the expropriated patent rights available to American pharmaceutical companies for $1; Lilly acquired the rights to methadone. In 1947, Lilly became the first distributor of methadone in the United States and marketed it under the trade name Dolophine. Methadone is an analgesic that is also widely used in the treatment of opioid use disorder.
== Proof == The detection as well as the quantitative determination of lactobacillic acid is carried out - as is usual for fatty acids - by gas chromatography of the methyl ester, often as gas chromatography with mass spectrometry coupling (GC/MS). Because of the cyclopropane ring, however, care must be taken to use a suitable methylation reagent. Not suitable, for example, is hydrogen chloride in anhydrous methanol, as this reagent can react with the cyclopropane ring, resulting in a branched-chain fatty acid with a methoxy group. However, sodium methanolate in anhydrous methanol is well suited, as is sodium hydroxide or potassium hydroxide in methanol. The formation of 3-pyridyl methyl esters (picolinyl esters) with nicotinyl alcohol is particularly recommended for structural elucidation using mass spectrometry methods. (pyridylmethanol) is recommended.
=== Rock Bottom Restaurant Breweries === The company operates 16 breweries under the name Rock Bottom Restaurant & Brewery. These breweries are located in several states, with five restaurants in Colorado, five in Illinois and one restaurant each in California, Florida, Maryland, Massachusetts, Minnesota and Virginia. The store was renamed Rock Bottom after someone pointed out that they were "building at the bottom of the rock," which was Prudential's slogan at the time. In 2000, the Boston-based Brew Moon Enterprises Inc. filed for bankruptcy and sold four of its five restaurant-microbreweries to Rock Bottom. In 2009, the La Jolla location in San Diego won a medal at the Great American Beer Festival, and in 2012 they medaled at the World Beer Cup. Rock Bottom Restaurants won Brewpub Group Brewer of the Year award at the 2013 Great American Beer Festival (GABF).
Sources: en.wikipedia.org
Suppliers normally quote a percentage of total chromatographic peak area, most often from reversed-phase HPLC. That figure says nothing about what the remaining percentage contains, and it depends on the detection wavelength used. A mass spectrometry result is a separate and stronger check on identity.
The methionine residue at the start of the chain is vulnerable to oxidation, producing a sulfoxide variant. Amide bonds can also hydrolyze, though more slowly under neutral conditions. Cold storage, oxygen exclusion and minimization of freeze-thaw cycles slow both processes but do not stop them.
A purity number on a certificate does not establish that a powder is the same product as a registered nasal medicine. Counter-ion content, residual solvents and peptide-related impurities may differ between the two. Independent verification is the only way to narrow that gap.
It originated at the Institute of Molecular Genetics in Moscow during the 1980s. The work was carried out by a Russian research group that specialized in peptide neuropharmacology.