This is a working overview of Intranasal route, written for readers who want more than a one-paragraph summary but less than a textbook.
Reviewed 2026-07-20. Anything still debated is marked as such rather than presented as settled.
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.
The compound was designed at the Institute of Molecular Genetics of the Russian Academy of Sciences during the 1980s and 1990s. The stated design goal was to retain the immunomodulatory and central nervous system activity attributed to tuftsin while improving resistance to enzymatic breakdown. Adding a proline-rich tail to the short parent peptide was a deliberate strategy, because proline residues restrict the conformations available to many peptidases. The same laboratory produced Semax, an ACTH fragment analog, and both compounds were developed in parallel as short, enzymatically stabilized peptides intended for intranasal use.
Reversed-phase high-performance liquid chromatography is the standard technique for estimating peptide purity. The result is a peak-area percentage, which describes how much of the detected material elutes as the main peak in one run. Mass spectrometry confirms the molecular mass and can reveal truncated, adducted, or otherwise modified species. Amino acid analysis or tandem mass spectrometry can address sequence fidelity when identity is in doubt. None of these measurements, taken alone, establishes that a sample is fit for any specific purpose.
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.
| Property | Value | Notes |
|---|---|---|
| Peptide sequence | Thr-Lys-Pro-Arg-Pro-Gly-Pro | Seven residues; tuftsin plus a Pro-Gly-Pro tail |
| Molecular formula | C33H57N11O9 | Commonly reported value for the free peptide |
| Monoisotopic mass | Roughly 751.4 Da | Average molecular mass near 751.9 Da |
| Appearance | White to off-white powder | Typically supplied as a lyophilized solid |
| Solubility class | Freely soluble in water | Also dissolves in saline and other polar solvents |
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.
Pharmacokinetic data are limited. Like most short peptides, Selank is vulnerable to plasma and tissue peptidases, and its measured half-life in circulation is short, on a minutes scale. The Pro-Gly-Pro tail slows this degradation but does not eliminate it. Intranasal administration is the route described in most reports, with absorption through the nasal mucosa and a hypothesized path into the central nervous system that avoids the blood-brain barrier. Direct measurements of human brain exposure are unavailable, so distribution claims rest on inference from animal work.
Clinical evidence comes mainly from small studies conducted in Russia, several of which were open-label or lacked robust blinding. Reported outcomes include lower anxiety scores, changes in attention measures, and effects on asthenic states following illness. Sample sizes are typically in the tens of participants, and independent replication outside the region is scarce. Reviews published in English generally note the limited methodological quality of the underlying trials. Whether the compound produces clinically meaningful effects under rigorous conditions remains unresolved.
Proposed mechanisms center on modulation of the GABA system, but no single molecular target has been confirmed. Rodent studies report changes in GABA-A receptor expression and in the turnover of serotonin, dopamine, and norepinephrine in several brain regions. Increases in brain-derived neurotrophic factor and its receptor have also been described after repeated administration. These findings come largely from animal models, and the degree to which they describe human neurochemistry remains an open question. The mechanism is best characterized as multi-system and not fully resolved.
== Hydrogen bonds in polymers == Hydrogen bonding plays an important role in determining the three-dimensional structures and the properties adopted by many proteins. Compared to the C−C, C−O, and C−N bonds that comprise most polymers, hydrogen bonds are far weaker, perhaps 5% as strong. Thus, hydrogen bonds can be broken by chemical or mechanical means while retaining the basic structure of the polymer backbone. This hierarchy of bond strengths (covalent bonds being stronger than hydrogen-bonds being stronger than van der Waals forces) is relevant in the properties of many materials.
Supermarket News ranked 7-Eleven's North American operations No. 11 in the 2007 "Top 75 North American Food Retailers", based on the 2006 fiscal year estimated sales of US$15.0 billion. Based on the 2005 revenue, 7-Eleven is the 24th largest retailer in the United States. As of 2013, 8,144 7-Eleven franchised units exist across the United States. Franchise fees range between US$10,000 – $1,000,000 and the ongoing royalty rate varies. 7-Eleven America has its headquarters in the Cypress Waters development in Irving, Texas. Small-size Slurpees are free on "7-Eleven Day", on July 11. This holiday first became widely celebrated on July 11, 2008, when first discovered by J. Brabank and C. Johnson. One exception is 2020, when the COVID-19 pandemic caused that year's cancellation. 7 Rewards members got a free medium Slurpee in their app instead. 7-Eleven Stores of Oklahoma operated independently beginning in 1953 under an agreement with the Brown family. As part of this franchise agreement, 7-Elevens in Oklahoma bore slight differences to stores elsewhere: for instance, products such as Big Bite hot dogs were not sold there, the Slurpee was branded as the "Icy Drink", and Oklahoma stores operated their own loyalty program called "Thx!", which did not intersect with the national 7Rewards system. On March 2, 2020, 7-Eleven, Inc. announced it had officially closed on the acquisition of over 100 of these independently operated 7-Eleven stores in Oklahoma. All of these 100 stores were in the greater Oklahoma City metropolitan area.
The Soviet Union imposed heavy controls on city growth, preventing some cities from reaching their full potential while promoting others. For the entirety of the Soviet Union's existence, the most populous cities were Moscow and Leningrad (both in Russian SFSR), with the third far place taken by Kiev (Ukrainian SSR). At the USSR's inception, the fourth and fifth most populous cities were Kharkov (Ukrainian SSR) and Baku (Azerbaijan SSR), but, by the end of the century, Tashkent (Uzbek SSR), which had assumed the position of capital of Soviet Central Asia, had risen to fourth place. Minsk (Byelorussian SSR) saw rapid growth during the 20th century, rising from the 32nd most populous in the union to the 7th.
== Location and campus == The college consists of an administrative block and self-contained blocks for the basic clinical departments. The college maintains a library, computer centre and a reading room.
== Supporting mass spectrometry == The dashboard provides support for mass spectrometry providing searches against the chemical data contained in the database based on mass and molecular formula. The dashboard has been applied to non-targeted analysis searching for "known unknowns". Both targeted mass spectrometry and non-targeted mass spectrometry are supported. The searches utilize a search based on "MS-Ready" forms of chemical compounds. Individual chemical substances are collapsed into a form that would be detected by mass spectrometry such that salts are desalted and neutralized and multi-component chemicals are separated into their individual components.
Sources: en.wikipedia.org
== Etymology == The word vegetable was first recorded in English in the early 15th century. It comes from Old French, and was originally applied to all plants; the word is still used in this sense in biological contexts. It derives from Medieval Latin vegetabilis "growing, flourishing" (i.e. of a plant), a semantic change from a Late Latin meaning "to be enlivening, quickening". The meaning of "vegetable" as a "plant grown for food" was not established until the 18th century. In 1767, the word was specifically used to mean a "plant cultivated for food, an edible herb or root". The year 1955 saw the first use of the shortened, slang term "veggie". As an adjective, the word vegetable is used in scientific and technical contexts with a different and much broader meaning, namely of "related to plants" in general, edible or not—as in vegetable matter, vegetable kingdom, vegetable origin, etc.
After hearing arguments for and against Luke, Viserys decides to reaffirm Luke's status as heir to Driftmark, which enrages Vaemond. Vaemond calls Rhaenyra a "whore" and her children "bastards", which angers Viserys into declaring that he will have Vaemond's tongue for such speech, though Daemon decapitates Vaemond before he can do so. Viserys hosts a feast among the two sides of his family, where he implores them to make amends for their past conflicts. Rhaenyra and Alicent compliment each other, and the family eats and laughs in harmony for the first time in years. Viserys is glad to see his family united, and departs for bed before Alicent and Rhaenyra's families become tense once again. As he lays in bed, Viserys mistakes Alicent for Rhaenyra and vocalizes Aegon the Conqueror's Song of Ice and Fire to her, with Alicent interpreting his words to mean that he wants her son Aegon to succeed him as king. He calls out to his "love" Aemma in his last words, and passes away shortly after on his bed.
=== Funding criteria === The NIH employs five broad decision criteria in its funding policy. First, ensure the highest quality of scientific research by employing an arduous peer review process. Second, seize opportunities that have the greatest potential to yield new knowledge and that will lead to better prevention and treatment of disease. Third, maintain a diverse research portfolio to capitalize on major discoveries in a variety of fields such as cell biology, genetics, physics, engineering, and computer science. Fourth, address public health needs according to the disease burden (e.g., prevalence and mortality). And fifth, construct and support the scientific infrastructure (e.g., well-equipped laboratories and safe research facilities) necessary to conduct research. Advisory committee members advise the institute on policy and procedures affecting the external research programs and provide a second level of review for all grant and cooperative agreement applications considered by the Institute for funding.
=== Protein identification === There are two main ways MS is used to identify proteins. Peptide mass fingerprinting uses the masses of proteolytic peptides as input to a search of a database of predicted masses that would arise from digestion of a list of known proteins. If a protein sequence in the reference list gives rise to a significant number of predicted masses that match the experimental values, there is some evidence that this protein was present in the original sample. Purification steps therefore limit the throughput of the peptide mass fingerprinting approach. Alternatively, peptides can be fragmented with MS/MS to more definitively identify them. MS is also the preferred method for the identification of post-translational modifications in proteins versus other approaches such as antibody-based methods.
== Contraindications == Sulfanilamide is contraindicated in those known to be hypersensitive to sulfonamides, in nursing mothers, during pregnancy near term, and in infants less than two months of age.
Sources: en.wikipedia.org
The sequence is Thr-Lys-Pro-Arg-Pro-Gly-Pro, written TKPRPGP in one-letter code. It combines the tetrapeptide tuftsin with a carboxyl-terminal Pro-Gly-Pro extension. This full sequence identifies the molecule more precisely than the research name.
No peptide with this exact sequence has been identified as an endogenous substance. It is a laboratory-designed analog of tuftsin, a naturally occurring immunomodulatory tetrapeptide. The Pro-Gly-Pro extension has no known natural source.
Proline introduces conformational constraints that make a peptide less accessible to common peptidases. This is a standard stabilization strategy in peptide design. The added residues also increase the distance between the active tuftsin portion and typical cleavage sites.
Sealed, desiccated storage at -20 °C or colder is the standard recommendation for research-grade material. Vials should reach room temperature before they are opened, which limits condensation. Repeated temperature cycling is discouraged.