heptapeptide is one of those subjects where the details matter more than the headlines. This page pulls together the background, the mechanisms, and the practical points readers ask about most.
Updated 2025-11-11. Numbers and descriptions here follow the published literature rather than marketing material.
Reported pharmacological work centers on neurotrophic signaling, including changes in BDNF and NGF expression in hippocampal tissue in animal models. Human data come largely from studies conducted in Russia, and how well those results generalize to other populations remains an open question. Regulatory status differs sharply by jurisdiction: Semax is a registered prescription medicine in Russia, while it holds no approved marketing status in the United States or the European Union. Outside such jurisdictions it is generally handled as a research chemical, which affects both documentation and quality expectations.
Semax is a synthetic heptapeptide whose sequence is Met-Glu-His-Phe-Pro-Gly-Pro. It was developed as a fragment analog of adrenocorticotropic hormone, modeled specifically on the ACTH(4-10) region. The first four residues reproduce that fragment, while a Pro-Gly-Pro tripeptide is appended at the C-terminus. Work on the compound originated in Russia, where it entered clinical use as an intranasal preparation. Its sequence places it among short regulatory peptides studied for effects on the central nervous system rather than on the adrenal axis.
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 normally supplied as a lyophilized powder, and that form is the most stable. Suppliers commonly recommend storage at -20 °C in a desiccated container protected from light, with short-term handling at room temperature limited to weighing and transfer. Powder that has absorbed moisture degrades faster, so vials should be warmed to ambient temperature before opening to prevent condensation on the contents. Hygroscopic behavior is typical of short hydrophilic peptides, and humidity control matters more than temperature alone for long-term retention.
| Property | Value | Notes |
|---|---|---|
| Molecular weight | ~813.9 Da (free heptapeptide) | N-acetylated form is about 42 Da heavier |
| Residue count | 7 (heptapeptide) | Four residues from ACTH(4-10), three added |
| Appearance | White to off-white powder | Usually supplied lyophilized |
| Solubility class | Freely soluble in water | Also dissolves in DMSO and polar organic solvents |
| Related parent fragment | ACTH(4-10) | Parent motif is Met-Glu-His-Phe |
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.
Published research has focused mainly on neurological and cognitive endpoints in animal models, with proposed mechanisms involving brain-derived neurotrophic factor and related signalling pathways. A substantial share of the human data originates from a limited number of research groups, and independent replication in other countries remains sparse. Regulatory status reflects that distribution: the peptide is registered as a medicine in Russia and appears in some neighbouring markets, while elsewhere it is handled as a research chemical without approved therapeutic labelling. Questions about dose-response relationships, long-term effects, and comparability across studies are still open.
Lyophilised powder is normally kept at -20 °C in a desiccated container, with some suppliers recommending -80 °C for long-term archival storage. Repeated freeze-thaw cycles are the most common cause of avoidable loss, so aliquoting before freezing reduces variability between working sessions. Dissolved peptide is far less stable than the dry solid and is usually prepared fresh or held briefly at 4 °C. Aqueous solutions support both hydrolysis of the backbone and oxidation of the N-terminal methionine, and these two routes dominate degradation under ordinary laboratory conditions.
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.
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.
Dissolution is normally performed in water, phosphate-buffered saline, or normal saline, since the peptide is freely soluble in aqueous media and is rarely handled with strong organic solvents. Solution pH should be kept near neutral, because extreme acidity or alkalinity accelerates backbone hydrolysis and encourages oxidation of the methionine side chain. Once dissolved, the material is less stable than the dry powder and is commonly divided into single-use portions and frozen. Buffers containing primary amines, such as Tris, are often avoided because of possible side reactions.
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.
== Epidemiology == Juvenile Idiopathic Arthritis is the most common chronic rheumatic disease of childhood. In high-income countries, yearly incidence has been estimated at 2–20 cases per 100,000 population; prevalence in these areas is estimated at 16–150 cases per 100,000 population. However, there is also a suggestion that these numbers underestimate disease prevalence: one community-based survey of school children in Western Australia reported a prevalence of 400 per 100,000. Overall prevalence is often reported as one per thousand children. Incidence and prevalence data vary across different population and ethnic groups, with lower overall prevalence in Afro-Caribbean and Asian populations. There are also ethnic differences in the frequency of JIA subtypes: for example, oligoarthritis is the most common subtype in European populations, whilst polyarticular disease predominates in many other countries including Costa Rica, India, New Zealand, and South Africa.
==== HKUST-1 ==== HKUST-1 consists of a dimeric Cu-paddlewheel that possesses two pore types. Under pelletization MOFs such as HKUST-1 exhibit a pore collapse. Although most carboxylate MOFs have a negative thermal expansion (they densify during heating), it was found that the hardness and Young's moduli unexpectedly decrease with increasing temperature from disordering of linkers. It was also found computationally that a more mesoporous structure has a lower bulk modulus. However, an increased bulk modulus was observed in systems with a few large mesopores versus many small mesopores even though both pore size distributions had the same total pore volume. The HKUST-1 shows a similar, "hyperfilling" phenomenon to the ZIF structures under hydrostatic loading.
The dominant narrative in the American Masonic histories for decades related that it was these American Freemasons who allowed Freemasonry to resurge in Cuba, but several modern historians write that it was the Cubans themselves who forced the resurgence, and the change in their government's approach to the nature of Freemasonry allowed them a sense of autonomy, rather than a complete dominance. Revolutionary GOCA exiles were allowed to return to the island, including its founder Aurelio Miranda y Álvarez, and Fernando Figueredo Socarrás. They met with Cuban Freemasons who had fought for independence in Cuba, such as José Fernández Pellón, Francisco de Paula Rodríguez, Gerardo L. Betancourt, Juan Bautista Hernández Barreiro, and Miguel Gener. When Governor Brooke officially assumed office, Miguel Gener, the Grand Commander of the Supreme Council, offered his respects to the General, and committed to cooperation with the North American bodies of Freemasonry. Soon after this, Gener was appointed to the office of Mayor of Havana. Freemasonry was "officially" reestablished in Cuba on February 5, 1899, when the Supreme Council of Colon and the Island of Cuba was reformed to become the Supreme Council of Cuba, which is the same Supreme Council that exists today. The United Grand Lodge of Colon and the Island of Cuba was reformed on March 26 to become the Grande Lodge of Cuba, at the same industrial property now owned by Padilla Lodge. Juan Bautista Hernández Barreiro was elected Grand Master, who simultaneously served as the government's Minister of Public Instruction.
There are some skeptics who think that the scratch created for the assay isn't a very accurate representation of an actual wound. This is very likely true as real wounds are inherently more complex, but this assay does allow for collective cell movements under defined experimental conditions to provide some insight. Despite it being described as straightforward, the technique has been criticized because of inconsistencies in its application from one experiment to another.
==== Indications ==== Nabilone, marketed under the brand name Cesamet®, is a synthetic form of tetrahydrocannabinol (THC). It is used to treat chemotherapy-induced nausea and vomiting in cancer patients who fail to have sufficient response to conventional antiemetic treatments. It is also used to treat anorexia and weight loss in AIDS patients.
Sources: en.wikipedia.org
=== Rowing === New Zealand Secondary School Championships (Maadi Cup) Maadi Cup (boys' U18 eight) – Westlake Boys High School Levin Jubilee Cup (girls' U18 eight) – St Margaret's College Star Trophy (overall points) – King's College
== Optimizing protein purification == Combinations of chromatographic methods can be used to purify a target molecule. The purpose of purifying proteins with FPLC is to deliver quantities of the target at sufficient purity in a biologically active state to suit its further use. The quality of the end product varies depending the type and amount of starting material, efficiency of separation, and selectivity of the purification resin. The ultimate goal of a given purification protocol is to deliver the required yield and purity of the target molecule in the quickest, cheapest, and safest way for acceptable results. The range of purity required can be from that required for basic analysis (SDS-PAGE or ELISA, for example), with only bulk impurities removed, to pure enough for structural analysis (NMR or X-ray crystallography), approaching >99% target molecule. Purity required can also mean pure enough that the biological activity of the target is retained. These demands can be used to determine the amount of starting material required to reach the experimental goal. If the starting material is limited and full optimization of purification protocol cannot be performed, then a safe standard protocol that requires a minimum adjustment and optimization steps are expected. This may not be optimal with respect to experimental time, yield, and economy but it will achieve the experimental goal.
When an anomeric center is involved in a glycosidic bond (as is common in nature) then one can distinguish between α- and β-glycosidic bonds by the relative stereochemistry of the anomeric position and the stereocenter furthest from C1 in the saccharide. Pharmacologists often join substances to glucuronic acid via glycosidic bonds in order to increase their water solubility; this is known as glucuronidation. Many other glycosides have important physiological functions.
=== Criminal use === In late August 2018, a South Carolina woman was charged with murdering her husband by putting eye drops containing tetryzoline in his drinking water. An autopsy found a high concentration of tetryzoline in his body. Tetryzoline has been used as a date rape drug in a number of cases because of its ability to cause dizziness and unconsciousness. In 2018, a 62 year-old woman in Pewaukee, Wisconsin, died in an apparent overdose or suicide involving tetryzoline and other substances; in November 2023 her caregiver was convicted of first-degree murder, following the allegation that her death was caused by a water bottle laced with Visine. In 2019, a North Carolina paramedic was accused of using tetryzoline eye drops to cause the death of his wife. The blood sample results showed about 30–40 times higher than the therapeutic level of tetryzoline.
Sources: en.wikipedia.org
In chemistry, an enantiomer (/ɪˈnænti.əmər, ɛ-, -oʊ-/ ih-NAN-tee-ə-mər), also known as an optical isomer, antipode, or optical antipode, is one of a pair of molecular entities which are mirror images of each other and non-superposable. Enantiomer molecules are like right and left hands: one cannot be superposed onto the other without first being converted to its mirror image. It is solely a relationship of chirality and the permanent three-dimensional relationships among molecules or other chemical structures: no amount of re-orientation of a molecule as a whole or conformational change converts one chemical into its enantiomer. Chemical structures with chirality rotate plane-polarized light. A mixture of equal amounts of each enantiomer, a racemic mixture or a racemate, does not rotate light. Stereoisomers include both enantiomers and diastereomers. Diastereomers, like enantiomers, share the same molecular formula and are also non-superposable onto each other; however, they are not mirror images of each other. In nature, most chiral compounds are only present as one enantiomer, such as amino acids—for example, only the L-isomer of alanine is incorporated into proteins.
This application of bicalutamide was also under review by the FDA in the U.S. in 2002, but ultimately was not approved in this country. In Japan, bicalutamide is licensed at a dosage of 80 mg/day alone or in combination with a GnRH analogue for prostate cancer. The unique 80 mg dosage of bicalutamide used in Japan was selected for development in this country on the basis of observed pharmacokinetic differences with bicalutamide in Japanese men. Subsequent to negative findings of bicalutamide monotherapy for LPC in the EPC clinical programme, approval of bicalutamide for use specifically in the treatment of LPC was withdrawn in a number of countries including the U.K. (in October or November 2003) and several other European countries and Canada (in August 2003). In addition, the U.S. and Canada explicitly recommended against the use of 150 mg/day bicalutamide for this indication. The drug is effective for, remains approved for, and continues to be used in the treatment of LAPC and mPC, on the other hand. The patent protection of bicalutamide expired in the U.S. in March 2009 and the drug has subsequently been available as a generic, at greatly reduced cost. Bicalutamide was the fourth antiandrogen (and the third NSAA) to be introduced for the treatment of prostate cancer, following the SAA CPA in 1973 and the NSAAs flutamide in 1983 (1989 in the U.S.) and nilutamide in 1989 (1996 in the U.S.).
Tissue transaminase activities can be investigated by incubating a homogenate with various amino/keto acid pairs. Transamination is demonstrated if the corresponding new amino acid and keto acid are formed, as revealed by paper chromatography. Reversibility is demonstrated by using the complementary keto/amino acid pair as starting reactants. After chromatogram has been taken out of the solvent the chromatogram is then treated with ninhydrin to locate the spots.
The same is true for vessels in air: a dirigible that weighs 100 tons needs to displace 100 tons of air. If it displaces more, it rises; if it displaces less, it falls. If the dirigible displaces exactly its weight, it hovers at a constant altitude. While they are related to it, the principle of flotation and the concept that a submerged object displaces a volume of fluid equal to its own volume are not Archimedes' principle. Archimedes' principle, as stated above, equates the buoyant force to the weight of the fluid displaced. One common point of confusion regarding Archimedes' principle is the meaning of displaced volume. Common demonstrations involve measuring the rise in water level when an object floats on the surface in order to calculate the displaced water. This measurement approach fails with a buoyant submerged object because the rise in the water level is directly related to the volume of the object and not the mass (except if the effective density of the object equals exactly the fluid density).
On 1 June 2020, the United States Pharmacopeia (USP) decided to cancel the proposal to include recombinant technology for endotoxin testing in chapter 85, Bacterial Endotoxins, and start the development of a separate chapter that expands on the use, validation, and comparability of endotoxin tests based on recombinantly derived reagents. A separate guidance-only chapter 1085.1 was proposed by the USP, though comments and feedback published on 11 December 2020 show that pharmaceutical companies and the FDA did not support this chapter and requested compendial status. In response, USP subsequently developed General Chapter <86>, Bacterial Endotoxins Test Using Recombinant Reagents, which provides compendial requirements for endotoxin testing using non-animal-derived reagents such as recombinant factor C (rFC). Chapter <86> became official in USP–NF in May 2025, establishing rFC as a pharmacopeially recognized alternative to the Limulus amebocyte lysate test.
Sources: en.wikipedia.org
The sequence is Met-Glu-His-Phe-Pro-Gly-Pro, a seven-residue peptide. The first four residues correspond to the ACTH(4-10) fragment, and Pro-Gly-Pro is added at the C-terminus. N-acetylated versions also appear in the literature and differ in mass.
Semax is a synthetic analog of the ACTH(4-10) fragment rather than a copy of the full hormone. Truncation plus the added tail removes the steroidogenic portion of ACTH. That distinction explains why it is studied for nervous-system effects instead of adrenal stimulation.
It is registered as a prescription product in Russia and has been used there clinically, chiefly by the intranasal route. No approval exists in the United States or the European Union. Availability elsewhere typically falls under research-chemical distribution, with varying purity documentation.
Each freeze-thaw cycle can degrade a fraction of the peptide and promote aggregation. Dividing a stock solution into single-use volumes removes repeated cycling as a variable. It also limits the time a thawed solution spends at room temperature.