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This page was last updated on 2025-10-19 and is reviewed periodically as new material appears.
Selank is a synthetic heptapeptide developed in Russia. Its sequence is Thr-Lys-Pro-Arg-Pro-Gly-Pro, a seven-residue chain built around the natural tetrapeptide tuftsin. Researchers at the Institute of Molecular Genetics of the Russian Academy of Sciences first described the compound in the mid-1990s. The design combined the tuftsin core with an added Pro-Gly-Pro tail, a modification intended to extend the molecule's stability in biological fluids. Published work on the peptide has appeared mainly in Russian-language journals.
Reported activity for Selank centers on anxiolytic and nootropic effects. Russian clinical reports describe use in anxiety and in cognitive or attention-related complaints. Most of this evidence comes from studies conducted by the same research groups that developed the peptide. Independent replication in other countries remains limited, and no major Western regulatory agency has approved the compound for any indication. The gap between local reports and external verification is a recurring point in discussions of the peptide.
Tuftsin, the parent structure, is a naturally occurring immunomodulatory tetrapeptide released from the Fc region of immunoglobulin G by spleen enzymes. Selank extends this four-residue sequence with three additional amino acids. The stated rationale is that the added tail slows enzymatic breakdown and may influence receptor interactions. How the full heptapeptide behaves at the molecular level is not firmly established, and proposed mechanisms often involve indirect modulation of neurotransmitter or immune signaling rather than a single defined target.
Selank is a hydrophilic peptide and dissolves readily in water and in aqueous buffers. The lyophilised powder is typically a white to off-white solid. Because short peptides are prone to hydrolysis and oxidation, handling benefits from limiting exposure to heat, moisture and strong light. Working solutions are commonly prepared in sterile water or saline, and repeated freeze-thaw cycles are avoided to reduce aggregation and loss of activity. These practices reflect general laboratory convention rather than published stability specifications.
Dry powder is normally held at -20 degrees Celsius or lower, in a sealed container with desiccant and protection from light. Reconstituted solutions are usually kept at 2 to 8 degrees Celsius for short periods and frozen for longer ones. Proline residues at several positions are generally associated with some resistance to peptidase attack, but chemical stability still declines at neutral to alkaline pH and at elevated temperature. Exact shelf-life figures are product-specific and are not standardised across suppliers.
| Property | Value | Notes |
|---|---|---|
| Chemical class | Synthetic heptapeptide | Modeled on tuftsin |
| Amino acid sequence | Thr-Lys-Pro-Arg-Pro-Gly-Pro | Seven residues |
| Approximate molecular mass | Around 750 Da | Depends on counter-ion and hydration |
| Common forms | Lyophilized powder | Also described as aqueous solution |
| Primary origin of research | Russian laboratories | Mid-1990s onward |
Lyophilized selank is normally supplied as a dry powder and is considered stable for extended periods when kept cold and dry. Moisture uptake is the main practical threat, because absorbed water promotes both hydrolysis and aggregation in the solid state. Vials are usually warmed to room temperature before opening so that condensation does not form on the powder. Supplier documentation commonly specifies -20 °C for routine storage, with -80 °C used for material intended to be archived for years.
Once dissolved, the peptide is markedly less stable than the dry powder. Aqueous solutions are subject to backbone hydrolysis and to microbial growth when they are handled without sterile technique. Buffered solutions near neutral pH are common for short-term laboratory work, while acidic conditions are sometimes used to improve solubility. Analytical laboratories generally prepare working solutions fresh rather than storing them, and a residual water film left in a reopened vial can seed degradation even when the container appears dry.
Laboratory work relies on standard behavioral paradigms. Rodents are tested in the elevated plus maze, open field, and passive avoidance tasks, with outcomes compared against diazepam or vehicle controls. Intranasal dosing is used most often because it bypasses first-pass metabolism, though intraperitoneal and intravenous routes also appear in published protocols. Biochemical endpoints include tissue BDNF concentrations, cytokine levels, and monoamine metabolites. Human data are limited to small Russian trials reporting reduced anxiety scores; most were not prospectively registered, and few employed independent outcome assessment.
Measuring peptide exposure inside the brain is technically difficult. Selank is degraded rapidly in plasma, and assays must separate intact peptide from fragments, which favors targeted mass spectrometry over immunoassays alone. Reported half-lives are short, on the order of minutes, so effects observed hours later are attributed to downstream signaling rather than to the parent compound. Blood-brain barrier permeability is debated and rarely quantified directly. Gaps include absent dose-response characterization, inconsistent reporting of purity, and almost no pharmacokinetic data from human participants.
Identity and purity of selank are established with reversed-phase high-performance liquid chromatography coupled to mass spectrometry. The peptide elutes from C18 columns with acetonitrile gradients in water containing trifluoroacetic acid or formic acid, and detection is usually performed by ultraviolet absorbance near 214 nm. Electrospray ionization in positive mode gives a doubly protonated ion near m/z 377, consistent with a mass of about 752 Da. Amino acid analysis or tandem mass spectrometry of fragment ions confirms the sequence. Because the molecule has no aromatic residues, it lacks a usable 280 nm chromophore, so low-wavelength detection or mass spectrometry is required.
Peptide bonds in selank are susceptible to hydrolysis under strongly acidic or basic conditions, and the terminal proline residues are vulnerable to exopeptidase activity in biological samples. Lyophilized powder stored dry at -20 °C typically remains stable for extended periods, whereas aqueous solutions degrade faster and may lose measurable purity within days to weeks depending on pH, temperature, and microbial load. Repeated freeze-thaw cycles promote aggregation and adsorption to container surfaces. For analytical work, solutions are usually prepared fresh, kept cold, and used within a single working day.
Handling follows standard practice for research peptides. Material is weighed in a low-humidity environment because the powder absorbs atmospheric moisture. Purity is reported as the percentage area of the main peak in a chromatogram, with specifications commonly set at 95 percent or higher; values below that threshold indicate the presence of truncated or modified species. Residual trifluoroacetate from purification is often present and may affect mass balance. Certificates of analysis should state the analytical method, the column and gradient used, and the lot-specific retention time so that results can be compared across suppliers.
However, the experimental chemistry of meitnerium has not received as much attention as that of the heavier elements from copernicium to livermorium. Lawrence Berkeley National Laboratory tried to synthesize 271Mt in 2002–2003 for a possible chemical investigation of meitnerium, as it was expected that it might be more stable than nearby isotopes due to having 162 neutrons, a magic number for deformed nuclei; its half-life was predicted to be a few seconds, long enough for a chemical investigation. However, no atoms of 271Mt were detected; this isotope of meitnerium is currently unknown. An experiment determining the chemical properties of a transactinide would need to compare a compound of that transactinide with analogous compounds of some of its lighter homologs: for example, in the chemical characterization of hassium, hassium tetroxide HsO4 was compared with the osmium analog, osmium tetroxide OsO4. In a preliminary step toward determining the chemical properties of meitnerium, the GSI attempted sublimation of rhodium(III) oxide Rh2O3 and rhodium(III) chloride RhCl3. However, macroscopic amounts of the oxide would not sublimate until 1000°C and the chloride would not until 780°C, and then only in the presence of carbon aerosol particles: these temperatures are far too high for such procedures to be used on meitnerium, as most of the current methods used for the investigation of the chemistry of superheavies do not work above 500°C.
== Function == NPR1 is a membrane-bound guanylate cyclase that serves as the receptor for both atrial and brain natriuretic peptides (ANP and BNP, respectively). It is localized in the kidney where it results in natriuresis upon binding to natriuretic peptides. However, it is found in even greater quantity in the lungs and adipocytes.
The puruṣamr̥ga plays a significant role in daily as well as yearly ritual of South Indian Hindu temples. In the Shodhasha-Upakaara (or sixteen honors) ritual, performed between one and six times at significant sacred moments through the day, it decorates one of the lamps of the Deepaaradhana or lamp ceremony. And in several temples the puruṣamr̥ga is also one of the vahana or vehicles of the deity during the processions of the Brahmotsava or festival. In Kanyakumari district, in the southernmost tip of the Indian subcontinent, during the night of Maha Shivaratri, devotees run 75 kilometres while visiting and worshiping at twelve Shiva temples. This Shiva Ottam or Running for Shiva is performed in commemoration of the story of the race between the Purushamirugam and Bhima, one of the Pandavas of the Hindu Epic Mahabharata. The Indian conception of a sphinx that comes closest to the classic Greco-Roman idea is the Sharabha and Gandabherunda, two mythical creatures, part lion, part human, part mammal and part bird, and the form of Sharabha that god Shiva took on and fought with the god Vishnu as Narasimha and Shiva as Sharabha was killed by Vishnu as Gandabherunda in the form of Narashima when Narashima killed Hiranyakashipu. In Sri Lanka and India, the sphinx is known as narasimha or human-lion. As a sphinx, it has the body of a lion and the head of a human being, and is not to be confused with Narasimha, the fourth incarnation of the deity Vishnu; this avatara or incarnation of Vishnu has a human body and the head of a lion and Vishnu as Narashima killed Hiranyakashipu.
Sources: en.wikipedia.org
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(CH2CH2)O + H2O → HO–CH2CH2–OH The reaction also occurs in the gas phase, in the presence of a phosphoric acid salt as a catalyst. The reaction is usually carried out at about 60 °C (140 °F) with a large excess of water, in order to prevent the reaction of the formed ethylene glycol with ethylene oxide that would form di- and triethylene glycol:
David Held (27 August 1951 – 2 March 2019) was a British political scientist who specialised in political theory and international relations; author of over twenty five scholarly academic texts and monographs. Basil Henriques Muriel Gray FRSE (born 30 August 1958) is a Scottish author, broadcaster and journalist, of Jewish ancestry. Gray has been a columnist for many publications, including Time Out magazine, the Sunday Correspondent, the Sunday Mirror, and Bliss magazine, and writes regularly for the Sunday Herald. and The Guardian. Zoë Heller author (Jewish father), daughter of screenwriter Lukas Heller; her paternal grandfather was the political philosopher Hermann Heller. Her brother is screenwriter Bruno Heller. Her sister, Lucy Heller Chief Executive of education charity Ark Noreena Hertz (born 24 September 1967) author, hosted "MegaHertz: London Calling", on SiriusXM's Insight channel and ITV News Economics Editor; wife of Danny Cohen (television executive), who previously held posts as Director of BBC Television and Controller of BBC One; from 1996 to 1997 she worked on the Middle East peace process with Palestinians, Egyptians, Israelis and Jordanians; honorary professor at University College London; Guardian op-ed writer.
Sources: en.wikipedia.org
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Manufacture and sale of sildenafil citrate drugs known as "generic Viagra" is common in India, where Pfizer's patent claim does not apply. Brand names include Kamagra (Ajanta Pharma), Silagra (Cipla), Edegra (Sun Pharmaceutical), Penegra (Zydus Cadila), Manly (Cooper Pharma) and Zenegra (Alkem Laboratories).
Sources: en.wikipedia.org
Selank is a synthetic peptide made of seven amino acids. It is modeled on tuftsin, a natural tetrapeptide, with an added three-residue tail. It is not a small-molecule drug.
It originates from research in Russia, associated with the Institute of Molecular Genetics of the Russian Academy of Sciences. The first descriptions date to the mid-1990s. Most published studies come from Russian laboratories.
No, Selank itself does not occur naturally. Its backbone is based on tuftsin, which is produced in the body, but the seven-residue version is a synthetic construct. It is supplied as a manufactured peptide.
Dry powder is normally held at -20 degrees Celsius or below in a sealed, light-protected container with desiccant. Brief room-temperature handling during weighing is generally tolerated. Storage instructions vary between suppliers, so the accompanying certificate of analysis should be followed.