This is a working overview of Certificate of analysis, written for readers who want more than a one-paragraph summary but less than a textbook.
This page was last updated on 2025-11-13 and is reviewed periodically as new material appears.
Development work on the compound began in the 1980s and 1990s at the Institute of Molecular Genetics in Moscow, within the same research programme that produced the peptide Semax. Early investigators sought a tuftsin derivative with improved resistance to enzymatic breakdown and with activity in the central nervous system after peripheral administration. Most of the primary literature from this period was published in Russian, a factor that still shapes how easily the findings can be checked by outside groups.
Naming for this compound is not fully standardised in English sources. The spelling Selanc appears in some transliterations, and catalogue entries may instead list the peptide sequence itself as the identifier. Reference material sometimes groups it with other short synthetic peptides studied for behavioural effects, which can create confusion when citations are compared. Distinguishing the exact sequence from related tuftsin analogues is therefore a practical first step when reviewing any dataset or specification sheet.
Selank is a synthetic heptapeptide with the sequence Thr-Lys-Pro-Arg-Pro-Gly-Pro, frequently abbreviated as TKPRPGP. It was designed as a structural analogue of tuftsin, a naturally occurring tetrapeptide released by enzymatic cleavage of the immunoglobulin heavy chain. The two additional proline residues at the C-terminal end extend the parent chain and change how the molecule behaves in solution. The free peptide has a calculated molecular mass of approximately 751.9 g/mol and is generally supplied as a lyophilised white to off-white powder.
Regulatory status differs sharply by region. Selank holds a Russian marketing authorization, where it is supplied mainly as nasal drops, while authorities elsewhere have not approved it for medical use. Material sold internationally is therefore usually labeled as a research chemical rather than a medicine. Peer-reviewed publications come predominantly from Russian laboratories, and sample sizes are generally small. Whether the compound produces comparable effects under independent, well-controlled replication remains an open question that the broader literature has not settled.
Selank is a synthetic heptapeptide developed in Russia as a structural analogue of tuftsin, a naturally occurring immunomodulatory tetrapeptide. Its sequence, Thr-Lys-Pro-Arg-Pro-Gly-Pro, keeps the tuftsin core at the N-terminus and appends a Pro-Gly-Pro tail. Researchers at the Institute of Molecular Genetics in Moscow synthesized the compound during the 1990s while searching for peptides with combined anxiolytic and immunomodulatory activity. The added tail was intended to resist enzymatic cleavage and prolong the molecule's presence in circulation.
The compound has a calculated molecular weight near 751.9 daltons and carries a net positive charge at physiological pH because of its arginine residue. It dissolves freely in water and in common aqueous buffers, and typically appears as a white or off-white lyophilized powder. The amide backbone makes the molecule susceptible to peptidases, which limits oral use and favors intranasal or parenteral routes. Nomenclature in the literature varies: the substance is also described by the sequence abbreviation TP-7 and by a Russian trade designation.
| Property | Value | Notes |
|---|---|---|
| Chemical class | Synthetic heptapeptide | Tuftsin analogue |
| Sequence | Thr-Lys-Pro-Arg-Pro-Gly-Pro | Single-letter form: TKPRPGP |
| Molecular formula | C33H57N11O9 | Calculated for the free peptide |
| Molecular weight | About 751.9 g/mol | Derived from the sequence |
| Appearance | White to off-white powder | Typical lyophilised form |
Enzymatic stability motivates the extra three residues at the carboxyl end. Native tuftsin is cleaved quickly by circulating aminopeptidases and carboxypeptidases, which limits its duration of action and its usefulness as a tool compound. Extending the chain with proline-rich segments is a common design tactic because proline constrains the backbone and slows proteolysis. The same Pro-Gly-Pro motif appears in other Russian-developed peptides of the era. Whether the full seven-residue chain is required for activity, or whether it acts mainly as a prodrug releasing tuftsin, remains unresolved.
Selank is a synthetic heptapeptide with the sequence Thr-Lys-Pro-Arg-Pro-Gly-Pro. Its four N-terminal residues reproduce tuftsin, a tetrapeptide fragment of the immunoglobulin heavy chain, while the C-terminal Pro-Gly-Pro extension is a synthetic addition. The peptide has a molecular mass near 752 daltons and carries a net positive charge at physiological pH because of the arginine and lysine side chains. Published indexes list it under the name Selank and the sequence abbreviation TKPRPGP. Solid-phase peptide synthesis is the standard production route for research quantities.
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.
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.
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.
Selank is studied chiefly as an animal-model anxiolytic with proposed secondary effects on memory and immune signaling. Reported mechanisms include modulation of the GABA-A receptor complex, inhibition of enkephalin-degrading enzymes, and shifts in monoamine turnover within limbic structures. Some experiments describe increased expression of brain-derived neurotrophic factor in the hippocampus after repeated dosing. No single molecular target has been confirmed, and the peptide does not bind any receptor with the selectivity typical of a conventional small-molecule drug. Mechanism therefore remains a set of hypotheses rather than an established pathway.
==== Elimination ==== Minoxidil is excreted almost exclusively (>97%) in urine. About 10 to 15% is excreted in urine unchanged. The elimination half-life of oral minoxidil is about 3 to 4 hours. Conversely, the half-life of topical minoxidil is 22 hours on average. Oral minoxidil is excreted within 12 to 20 hours in urine. Despite this however, the hypotensive effect of oral minoxidil lasts approximately 72 hours following a single dose. With discontinuation of topical minoxidil, about 95% of systemically absorbed minoxidil is excreted within 4 days. The renal clearance of oral minoxidil is 352 mL/minute.
=== Norwegian === According to Guinness Book of Records (2001), the longest meaningful word used in Norwegian is minoritetsladningsbærerdiffusjonskoeffisientmålingsapparatur (63 letters), meaning devices for measuring coefficients of diffusion of carriers of minority charges. Nouns, and also verbs and adjectives, can be prefixed as qualifiers to other words quite freely, e.g. to make an unlikely, but understandable and grammatically correct, compound word like damplokomotivfyrbøteraspirantluemerkeprodusentdatterkinoavtaletidspunkt, an agreed meeting time for a cinema date with a daughter of a producer of hat badges for trainees aiming to become firemen on steam locomotives.
In Britain, a number of different filmmakers came together under John Grierson. They became known as the Documentary Film Movement. Grierson, Alberto Cavalcanti, Harry Watt, Basil Wright, and Humphrey Jennings amongst others succeeded in blending propaganda, information, and education with a more poetic aesthetic approach to documentary. Examples of their work include Drifters (John Grierson), Song of Ceylon (Basil Wright), Fires Were Started, and A Diary for Timothy (Humphrey Jennings). Their work involved poets such as W. H. Auden, composers such as Benjamin Britten, and writers such as J. B. Priestley. Among the best-known films of the movement are Night Mail and Coal Face. Calling Mr. Smith (1943) is an anti-Nazi color film created by Stefan Themerson which is both a documentary and an avant-garde film against war.
Hypoglycemia is a condition that occurs when blood glucose levels decrease below normal, causing symptoms including anxiety, tremors, nausea, palpitations, confusion, and coma. Individuals with diabetes or other conditions that result in low blood sugar may carry glucose tablets, oral glucose gel, hard candy, or sugar packets to use when their blood sugar becomes too low. Severe low blood sugar can lead to confusion, coma, neurological damage and other potentially serious complications, making it unsafe to administer glucose by mouth. In these cases, dextrose (D-glucose) can be administered into a vein to quickly and directly raise blood glucose levels.
To allow comparison of results between people of different sizes, the CCr is often corrected for the body surface area (BSA) and expressed compared to the average sized man as mL/min/1.73 m2. While most adults have a BSA that approaches 1.7 m2 (1.6 m2 to 1.9 m2), extremely obese or slim patients should have their CCr corrected for their actual BSA.
Sources: en.wikipedia.org
== General references == Colonial Reports. Aden Report: 1953 & 1954, HM Stationery Office 1956. Paul Dresch. A History of Modern Yemen. Cambridge, UK: Cambridge University Press, 2000. R.J. Gavin. Aden Under British Rule: 1839–1967. London: C. Hurst & Company, 1975. Gillian King. Imperial Outpost: Aden: Its Place in British Foreign Policy. Chatham House Essay Series, 1964. H. J. Liebensy. Administration and Legal Development in Arabia. Middle East Journal, 1955. Tom Little. South Arabia: Arena of Conflict. London: Pall Mall Press, 1968. Elizabeth Monroe. Kuwayt and Aden: A Contrast in British Policies. Middle East Journal, 1964. Newsinger, John (2012). British Counterinsurgency. London: Springer. ISBN 978-1137316868. E. H. Rawlings. The Importance of Aden. Contemporary Review, 195, 1959. Jonathan Walker. Aden Insurgency: The Savage War in South Arabia 1962–67, Spellmount, 2004. D. C. Watt. Labour Relations and Trade Unionism in Aden: 1952–60. Middle East Journal, 1962.
Usually the largest workers in the colony develop into repletes; and, if repletes are removed from the colony, other workers become repletes, demonstrating the flexibility of this particular polymorphism. This polymorphism in morphology and behaviour of workers initially was thought to be determined by environmental factors such as nutrition and hormones that led to different developmental paths; however, genetic differences between worker castes have been noted in Acromyrmex sp. These polymorphisms are caused by relatively small genetic changes; differences in a single gene of Solenopsis invicta can decide whether the colony will have single or multiple queens. The Australian jack jumper ant (Myrmecia pilosula) has only a single pair of chromosomes (with the males having just one chromosome as they are haploid), the lowest number known for any animal, making it an interesting subject for studies in the genetics and developmental biology of social insects.
In molecular biology, the Signal Peptide Peptidase (SPP) is a type of protein that specifically cleaves parts of other proteins. It is an intramembrane aspartyl protease with the conserved active site motifs 'YD' and 'GxGD' in adjacent transmembrane domains (TMDs). Its sequences is highly conserved in different vertebrate species. SPP cleaves remnant signal peptides left behind in membrane by the action of signal peptidase and also plays key roles in immune surveillance and the maturation of certain viral proteins.
== Function == Mambalgins are potent inhibitors of acid-sensing ion channels (ASICs), which are multimeric membrane proteins that respond to low pH and whose activation is thought to be involved in perception of pain. Mambalgins have been shown to interact specifically with ASIC subtypes present in the central nervous system (homomeric ASIC1a and heteromeric ASIC1a/ASIC2a or ASIC1a/ASIC2b), as well as those found in sensory neurons (ASIC1b and ASIC1a/ASIC1b). They have no effect on other ASICs or on other types of ion channel proteins. These interactions are likely mediated in part by mambalgins' positive electrostatic potential facilitating binding to negatively charged ASICs. Mambalgins are believed to trap ASICs in a closed conformation. In tests performed on laboratory mice, mambalgins have the in vivo effect of analgesia without the toxic effects seen with most 3FTx proteins, and in particular, without the clinical manifestations associated with inhibition of nicotinic acetylcholine receptors, the targets of most 3FTx proteins including mambalgins' closest relatives. Furthermore, the analgesic effects of mambalgins does not confer side effects such as respiratory depression and drug tolerance, both associated with opioid analgesics.
==== Removal of the spleen ==== The spleen is the organ which removes damaged or misshapen red blood cells from the circulation. In thalassemia, this can lead to the spleen becoming enlarged, a condition known as splenomegaly. Slight enlargement of the spleen is not a problem, however if it becomes extreme then surgical removal of the spleen (splenectomy) may be recommended.
Sources: en.wikipedia.org
The sequence is Thr-Lys-Pro-Arg-Pro-Gly-Pro, commonly written as TKPRPGP. It shares the first four residues with tuftsin and carries three prolines in the chain. The proline-rich tail is the main structural feature that separates it from the parent tetrapeptide.
Selank is a synthetic analogue built on the tuftsin tetrapeptide Thr-Lys-Pro-Arg. Extra proline residues were added to the C-terminus during design work. That modification is intended to make the peptide less vulnerable to rapid enzymatic degradation.
Transliteration from Russian produces variant spellings such as Selanc. Many suppliers avoid the trade-style name entirely and list the peptide sequence. Comparing sequences rather than names is the reliable way to confirm two entries describe the same molecule.
Selank is a synthetic seven-amino-acid peptide modeled on tuftsin, a fragment of the immunoglobulin G heavy chain. It was designed in Russia to combine anxiolytic and immunomodulatory properties in one molecule.