The short version of Certificate of analysis fits in a sentence. The long version — which is the one that helps — is below.
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Published clinical evidence is limited. Most controlled trials were conducted in Russia, enrolled modest numbers of participants, and appeared in Russian-language journals, which restricts independent verification. Reported outcomes include lower anxiety scores, improved attention and memory measures, and changes in fatigue ratings. Reviews written in English note methodological limitations such as small samples and inconsistent endpoints. Whether the compound produces clinically meaningful benefit relative to established anxiolytics is therefore an open question rather than an established finding.
Selank is a synthetic heptapeptide with the sequence Thr-Lys-Pro-Arg-Pro-Gly-Pro. It was designed at the Institute of Molecular Genetics of the Russian Academy of Sciences as a structural analogue of tuftsin, a naturally occurring tetrapeptide fragment of the immunoglobulin heavy chain. The added Pro-Gly-Pro tail was intended to slow enzymatic degradation and extend biological activity. In Russia it is registered as an anxiolytic nasal preparation, while regulators elsewhere have not approved it for clinical use.
Proposed mechanisms centre on modulation of the GABAergic system, with reports of altered expression of genes related to GABA-A receptor subunits and changed monoamine turnover. Some studies describe inhibition of enkephalinase, the enzyme that degrades endogenous enkephalins, which may prolong opioid peptide signalling. Effects on brain-derived neurotrophic factor and on cytokine expression have also been reported. These findings come largely from animal models and small human studies, and the precise primary target remains unresolved.
Animal studies have examined behaviour in tests of anxiety, memory retention and stress response, and several report changes in neurotrophic or neurotransmitter-related markers. The human evidence base is much smaller, consisting mainly of short trials conducted in Russia with limited reporting in English-language journals. Sample sizes are modest and outcome measures vary between studies, so the findings are best described as preliminary. Independent replication under modern trial standards has not been widely reported.
Outside its country of origin the compound is generally handled as a research chemical rather than an approved medicine. No regulatory approval from the United States Food and Drug Administration or the European Medicines Agency has been granted for human use. Identity and purity are normally checked by reverse-phase high-performance liquid chromatography, with mass spectrometry used to confirm the molecular mass. Lyophilised material is stored cold and desiccated, and repeated freeze-thaw cycles are avoided.
Published work on this peptide almost always uses intranasal delivery, with drops or a spray applied to the nasal mucosa. Some animal experiments have used subcutaneous or intraperitoneal injection, and a smaller number have compared routes directly. Oral administration is not a focus of the literature, because short peptides of this size are broken down by digestive enzymes and cross intestinal barriers poorly. How much of an intranasal dose reaches the bloodstream intact in humans remains an open question.
| Property | Value | Notes |
|---|---|---|
| Molecular formula | C33H57N11O9 | Free peptide form |
| Molecular mass | About 751.9 Da | Calculated average mass |
| Amino acid sequence | Thr-Lys-Pro-Arg-Pro-Gly-Pro | Single-letter form TKPRPGP |
| Structural basis | Tuftsin analogue | Extended version of a natural tetrapeptide |
| Development origin | Russian Academy of Sciences | Work carried out from the 1980s onward |
Selank is not a naturally occurring peptide and has no known endogenous counterpart in human physiology. Russian-language sources frequently call it TP-7, while English-language sources use the name Selank almost exclusively. Database indexing is uneven, partly because early reports appeared in regional journals that are not widely cataloged. Some summaries describe the material as a tuftsin analog and others as a synthetic heptapeptide; the labels overlap rather than conflict. Citing the primary sequence resolves ambiguity more reliably than the research or trade name alone.
Selank is a synthetic heptapeptide with the sequence Thr-Lys-Pro-Arg-Pro-Gly-Pro, written TKPRPGP in one-letter notation. Its structure consists of the immunomodulatory tetrapeptide tuftsin, Thr-Lys-Pro-Arg, extended at the carboxyl terminus by a Pro-Gly-Pro segment. The molecular formula is commonly given as C33H57N11O9, corresponding to a monoisotopic mass near 751.4 Da and an average molecular mass near 751.9 Da. All seven residues are proteinogenic amino acids, and the molecule carries no modified side chains or non-natural linkages.
Quality assessment of Selank samples typically combines purity determination with identity confirmation and counter-ion analysis. Purity is usually reported as a percentage by chromatographic area, with values above 95 percent often quoted for research-grade material. Water content and residual solvents are checked in lyophilized batches because they affect both stability and accurate mass determination. A reported purity figure does not by itself establish that a sample is the intended sequence, so orthogonal methods are needed to rule out sequence isomers or truncation products.
Characterization of Selank in laboratory settings relies on standard peptide analytical techniques. Reverse-phase high-performance liquid chromatography separates the peptide from related impurities and degradation products, while mass spectrometry confirms molecular identity through accurate mass measurement. Amino acid analysis and peptide sequencing verify the primary structure when reference material is unavailable. Because Selank is a short chain, fragmentation-based analysis produces a diagnostic ion pattern that supports confident identification.
Published clinical work is concentrated in Russian-language journals and generally involves small samples without independent replication. Systematic reviews in English note the shortage of randomised, placebo-controlled trials and the difficulty of verifying methods from translated reports. Outcome measures vary between studies, which complicates pooling of results. Interest in the compound as a cognitive or anxiolytic agent therefore rests on a thinner evidence base than the volume of citations suggests. Replication in well-powered trials with preregistered endpoints would be needed before firm conclusions about efficacy can be drawn.
Proposed mechanisms centre on the GABAergic system. Animal and tissue studies report changes in GABA-A receptor expression and reduced activity of GABA transaminase, the enzyme that degrades GABA. Effects on monoamine turnover, including serotonin and dopamine pathways, are also described, and a separate line of work links the peptide to increased expression of brain-derived neurotrophic factor in hippocampal tissue. Most of these findings come from rodent models and cell preparations. How the individual observations combine into a single coherent mode of action is not settled.
Pharmacokinetic data are sparse and largely derived from animal work. After intranasal administration the peptide appears in plasma within minutes, and reported half-lives are short, on the order of minutes to tens of minutes. Degradation proceeds through ordinary proteolytic cleavage into constituent amino acids and smaller fragments. Direct evidence that intact Selank reaches brain tissue in meaningful amounts is limited, and the extent of blood-brain barrier penetration is debated. Some authors argue that fragments, not the parent peptide, carry much of the observed activity.
Reverse-phase high-performance liquid chromatography with ultraviolet detection near 214 nanometres is the standard purity method. Mass spectrometry, typically electrospray ionisation, confirms identity through the expected mass-to-charge pattern. Amino acid analysis can verify composition independently. Chiral purity requires separate techniques such as derivatisation followed by chromatographic separation, and such data are rarely reported for research-grade material.
Quantification in biological matrices relies on liquid chromatography coupled to tandem mass spectrometry with stable-isotope internal standards. Low plasma concentrations and adsorption to container surfaces both complicate measurement. Solid-phase extraction is often needed to reduce matrix interference before injection. Reported limits of quantification differ widely between laboratories, which makes direct comparison of pharmacokinetic results difficult and limits meta-analysis.
Peptide bonds are vulnerable to protease attack, and Selank is no exception. Measured half-life in serum is short, on the order of minutes in several reports, which explains why intranasal administration is the common route described in the literature. Absorption across the nasal mucosa partially bypasses first-pass hepatic metabolism. Quantitative data on human bioavailability remain limited and are difficult to compare across studies.
=== Breastfeeding === Paracetamol is excreted in breast milk at measurable concentrations (milk/plasma ratio approximately 1), but the amount ingested by the infant is much lower than paediatric therapeutic doses and rarely associated with clinical effects. Use during breastfeeding is considered compatible at recommended doses, with extra caution for preterm infants or infants with liver disease.
== External links == The MEROPS online database for peptidases and their inhibitors: A02.001 Archived 2005-01-23 at the Wayback Machine Proteopedia HIV-1_protease - the HIV-1 protease structure in interactive 3D. Proteopedia Flaps_Morph_for_HIV_Protease - Animation of the flaps opening and closing based on X-ray crystal structures. HIV-1+Protease at the U.S. National Library of Medicine Medical Subject Headings (MeSH)
Some historians assert that as many as 17 million people were sold into slavery on the coast of the Indian Ocean, the Middle East, and North Africa, and approximately 5 million African slaves were bought by Muslim slave traders and taken from Africa across the Red Sea, Indian Ocean, and Sahara Desert between 1500 and 1900. The captives were sold throughout the Middle East. This trade accelerated as superior ships led to more trade and greater demand for labour on plantations in the region. Eventually, tens of thousands of captives were being taken every year. The Indian Ocean slave trade was multi-directional and changed over time. To meet the demand for menial labour, Bantu slaves bought by east African slave traders from southeastern Africa were sold in cumulatively large numbers over the centuries to customers in Egypt, Arabia, the Persian Gulf, India, European colonies in the Far East, the Indian Ocean islands, Ethiopia, Sudan and Somalia. According to the Encyclopedia of African History, "It is estimated that by the 1890s the largest slave population of the world, about 2 million people, was concentrated in the territories of the Sokoto Caliphate. The use of slave labour was extensive, especially in agriculture." The Anti-Slavery Society estimated there were 2 million slaves in Ethiopia in the early 1930s out of an estimated population of 8 to 16 million. Slave labour in East Africa was drawn from the Zanj, Bantu peoples that lived along the East African coast.
Innate immune response cells such as dendritic cells engulf pathogens through a process called phagocytosis. Dendritic cells then migrate to the lymph nodes where T cells (adaptive immune cells) wait for signals to trigger their activation. In the lymph nodes, dendritic cells mince the engulfed pathogen and then express the pathogen clippings as antigen on their cell surface by coupling them to a special receptor known as a major histocompatibility complex. T cells can then recognize these clippings and undergo a cellular transformation resulting in their own activation. γδ T cells possess characteristics of both the innate and adaptive immune responses. Macrophages can also activate T cells in a similar approach (but do not do so naturally). This process carried out by both dendritic cells and macrophages is termed antigen presentation and represents a physical link between the innate and adaptive immune responses. Upon activation, mast cells release heparin and histamine to effectively increase trafficking to and seal off the site of infection to allow immune cells of both systems to clear the area of pathogens. In addition, mast cells also release chemokines which result in the positive chemotaxis of other immune cells of both the innate and adaptive immune responses to the infected area. Due to the variety of mechanisms and links between the innate and adaptive immune response, an adjuvant-enhanced innate immune response results in an enhanced adaptive immune response.
Sources: en.wikipedia.org
=== Sound production === The ability to produce sound for communication appears to have evolved independently in several teleost lineages. Sounds are produced either by stridulation or by vibrating the swim bladder. In the Sciaenidae, the muscles that attach to the swim bladder cause it to oscillate rapidly, creating drumming sounds. Marine catfishes, sea horses and grunts stridulate by rubbing together skeletal parts, teeth or spines. In these fish, the swim bladder may act as a resonator. Stridulation sounds are predominantly from 1000–4000 Hz, though sounds modified by the swim bladder have frequencies lower than 1000 Hz.
==== New album: Criminal Migraine (2026–present) ==== On August 17, 2026, Ice-T released a new double album, Criminal Migraine, for digital download independently through his website. This is Ice's first new rap album in 20 years, since Gangsta Rap was released in 2006. The new album is not available on any streaming service and features guest appearances by Treach, Smoothe Da Hustler, CJ Mac and Ras Kass.
=== Spring 2003 === A US veteran sergeant reports witnessing torture of journalists and writers all over Iraq. Kurdistan region was not an exception. Writers without Borders embarrassed the Iraqi government quite frequently in reports covering minority, women and marginalised Iraqis from all over the country but with much focus on Baghdad, Karkuk, Salahedin and Mosul. Honorably discharged US veteran, Sergeant Frank "Greg" Ford reports that he witnessed war crimes in Samarra, Iraq. According to Ford, several members of his own unit, the 205th Military Intelligence Brigade participated in the torture of Iraqi detainees as young as 14. Ather Karen al-Mowafakia died in Basra, while in British custody. Details about the investigation are not known. Gary Bartlam, a British soldier of the 7th Armoured Brigade, was arrested after submitting film to a photo developers shop in Tamworth, England while on leave. The photographs depict a gagged Iraqi POW suspended hanging by rope from a fork lift, and other pictures seem to show prisoners being forced to perform sexual acts. Bartlam and two other soldiers were convicted at court martial of abuse - a fourth soldier was cleared. British Lieutenant Colonel Tim Collins was alleged by US Army Major Re Biastre to have been responsible for mistreatment of Iraqi civilians and prisoners of war. Lieutenant Colonel Collins was later cleared of any wrongdoing by an MOD investigation.
== Terminology == In the United Kingdom, the name or names of the fruit followed by juice can only legally be used to describe a product that is 100% fruit juice, as required by the Fruit Juices and Fruit Nectars (England) Regulations and the Fruit Juices and Fruit Nectars (Scotland) Regulations 2003. However, a juice made by reconstituting concentrate can be called juice. A product described as fruit "nectar" must contain at least 25% to 50% juice, depending on the fruit. A juice or nectar including concentrate must state that it does. The term "juice drink" is not defined in the Regulations and can be used to describe any drink that includes juice, whatever the amount. Comparable rules apply in all EU member states in their respective languages. In the US, fruit juice can only legally be used to describe a product that is 100% fruit juice. A blend of fruit juice(s) with other ingredients, such as high-fructose corn syrup, is called a juice cocktail or juice drink. According to the Food and Drug Administration (FDA), the term "nectar" is generally accepted in the US and in international trade for a diluted juice to denote a beverage that contains fruit juice or puree, water, and artificial sweeteners. "No added sugar" is commonly printed on the labels of juice containers, but the products may contain large amounts of naturally occurring sugars; however, sugar content is listed with other carbohydrates on labels in many countries.
Sanctions against Eritrean President Isaias Afewerki' People's Front for Democracy and Justice and Eritrean forces are lifted by the Trump administration "to advance US regional interests" in the Red Sea. September 22 – The cybercrime group ShinyHunters claims to have breached the Federal Bureau of Investigation's jobs portal and stolen personal data belonging to thousands of current and former FBI employees and job applicants. The FBI opens an investigation, while Reuters partially verifies a sample containing names, addresses, Social Security numbers and details of sensitive intelligence assignments. September 23 Iranian president Masoud Pezeshkian arrives in New York to speak at the United Nations General Assembly, the first time an elected leader from a nation at war with the United States sets foot on American soil to address a UN gathering. Movie magnate Harvey Weinstein is sentenced to 15 years in prison after being convicted of sexually assaulting former TV production assistant Miriam Haley in 2006 at his Manhattan apartment. September 24 A federal judge rules that Trump's White House ban on journalists from CNN, MS NOW, and Politico likely breached the First Amendment and due process clause and orders access to be reinstated. The Navy confirms that eight sailors from the USS Lincoln group, which spent a record-setting amount of time at sea in support of the Iran war, attempted suicide.
Sources: en.wikipedia.org
It is a seven-amino-acid peptide, Thr-Lys-Pro-Arg-Pro-Gly-Pro, produced by chemical synthesis rather than extracted from biological tissue. Its design is based on tuftsin, a natural immunomodulatory tetrapeptide. The C-terminal Pro-Gly-Pro segment is a common stabilising motif in short regulatory peptides.
The core four residues correspond to tuftsin, which occurs naturally as part of immunoglobulin G. The full seven-residue sequence, however, is not a known endogenous peptide. It is a laboratory-designed analogue intended to combine tuftsin-like activity with greater resistance to breakdown.
No single receptor has been confirmed as the primary target. Reports describe involvement of the GABAergic system, interference with enkephalin degradation, and shifts in neurotrophic factor expression. Because these observations come from different models and assays, they have not yet been integrated into one accepted mechanism.
Most published work uses intranasal application, either as drops or as a nasal spray. Injection routes appear in a smaller set of animal experiments. Oral use is uncommon in the literature because peptide breakdown and poor absorption limit this route.