Intranasal delivery raises a handful of sensible questions. This page answers them in order, starting with the fundamentals and moving to applications.
This page was last updated on 2025-08-28 and is reviewed periodically as new material appears.
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.
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.
| Property | Value | Notes |
|---|---|---|
| Common route | Intranasal | Also injected in some animal work |
| Solubility class | Freely soluble in water | Solid form is hygroscopic |
| Typical storage | About -20 degrees Celsius | Keep desiccated and dark |
| Purity method | Reverse-phase HPLC | Reported as area percent |
| Confirmatory method | Mass spectrometry | Verifies expected molecular mass |
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.
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.
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.
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.
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.
as it was in the general continuum equations and in the incompressible flow section. The compressible momentum Navier–Stokes equation results from the following assumptions on the Cauchy stress tensor:
The most common dashi stocks for miso soup are made of niboshi (dried baby sardines), kombu (dried kelp), katsuobushi (thin shavings of fermented, dried, and smoked bonito), or hoshi-shiitake (dried shiitake). The kombu can also be used with katsuobushi or hoshi-shiitake. Kelp or shiitake dashi give a vegetarian soup stock. When the soup includes clams such as asari, shijimi, or hamaguri, prepared dashi is often not used. Outside Japan, American- or European-style miso soup is sometimes made by dissolving miso in a Western vegetable stock. It can also be made with chicken broth. The stock might include ingredients such as negi, carrot, potato and daikon radish. In some versions of the dish, chicken stock, Western-style fish stock, and other non-dashi bases can even be used, but there is some debate over whether or not miso soups made using these non-traditional bases count as true miso soup.
== Interaction of free protons with ordinary matter == Although protons have affinity for oppositely charged electrons, this is a relatively low-energy interaction and so free protons must lose sufficient velocity (and kinetic energy) in order to become closely associated and bound to electrons. High energy protons, in traversing ordinary matter, lose energy by collisions with atomic nuclei, and by ionization of atoms (removing electrons) until they are slowed sufficiently to be captured by the electron cloud in a normal atom. However, in such an association with an electron, the character of the bound proton is not changed, and it remains a proton. The attraction of low-energy free protons to any electrons present in normal matter (such as the electrons in normal atoms) causes free protons to stop and to form a new chemical bond with an atom. Such a bond happens at any sufficiently "cold" temperature (that is, comparable to temperatures at the surface of the Sun) and with any type of atom. Thus, in interaction with any type of normal (non-plasma) matter, low-velocity free protons do not remain free but are attracted to electrons in any atom or molecule with which they come into contact, causing the proton and molecule to combine. Such molecules are then said to be "protonated", and chemically they are simply compounds of hydrogen, often positively charged. Often, as a result, they become so-called Brønsted acids. For example, a proton captured by a water molecule in water becomes hydronium, the aqueous cation H3O+.
=== Peptide Folding === Coupling ribosome profiling with ChIP can elucidate how and when newly synthesized proteins are folded. Using the footprints provided by Ribo-Seq, specific ribosomes associated with factors, like chaperones, can be purified. Pausing the ribosome at specific time points, allowing it to translate a polypeptide over time, and exposing the different points to a chaperone and precipitating out using ChIP purifies these samples and can show at which point in time the peptide is being folded.
=== 116th Congress (2019–2021) === In March 2019, Kennedy introduced the Holding Foreign Companies Accountable Act, which Trump signed into law on December 18, 2020. The law prohibits any company from listing on an American stock exchange if it refuses to allow the Public Company Accounting Oversight Board to audit its annual private audit for three consecutive years. It also requires companies to disclose whether they are owned by a foreign government. In 2019, Kennedy again introduced a bill to extend the National Flood Insurance Program. It extended the program through June 14, 2019, rather than lapsing on May 31. The bill passed the Senate on May 23, 2019, and was signed into law.
Sources: en.wikipedia.org
=== General and cited references === Chinn, George M., ed. (1987). The Machine Gun: History, Evolution, and Development of Manual, Automatic, and Airborne Repeating Weapons (PDF). Vol. V. Ann Arbor, Michigan: Edward Brothers Publishing Co. Retrieved 28 April 2019.
Emdogain which has been shown to significantly improve probing attachment levels (1.1mm) and periodontal pocket depth reduction (0.9mm) when compared to a placebo or control materials. Resorption rates ranging from six to 24 weeks depending on its different chemical structures. With the resorbable membrane used, the membrane will bio-degrade. There is no need for a second surgery to remove the membrane, this will prevent any disruption to the healing process of the regenerated tissues. A synthetic resorbable membrane (eg: Powerbone Barrier Membrane) is an ideal alternative to the resorbable collagen material. Randomised clinical trials compared the stability of augmented bone between a synthetic resorbable membrane and a collagen membrane with guided bone regeneration simultaneous to dental implant placement in the aesthetic zone in terms of facial bone thickness. Success depends on several factors: osteoblasts being present at the site, a sufficient blood supply, stabilisation of the graft during healing, and soft tissue not being under tension.
== Chemical and physical properties == Zearalenone is a white crystalline solid, with molecular formula C18H22O5 and 318.364 g/mol molecular weight. It is a resorcyclic acid lactone. It exhibits blue-green fluorescence when excited by long wavelength ultraviolet (UV) light (360 nm) and a more intense green fluorescence when excited with short wavelength UV light (260 nm). In methanol, UV absorption maxima occur at 236 (e = 29,700), 274 (e = 13,909) and 316 nm (e = 6,020). Maximum fluorescence in ethanol occurs with irradiation at 314 nm and with emission at 450 nm. Solubility in water is about 0.002 g/100 mL. It is slightly soluble in hexane and progressively more so in benzene, acetonitrile, methylene chloride, methanol, ethanol, and acetone. It is also soluble in aqueous alkali. The naturally occurring isomer trans-zearalenone (trans-ZEN) is transformed by ultraviolet irradiation to cis-zearalenone (cis-ZEN).
28 February to 8 May The U.S. 101st Airborne Division and ARVN 1st Division launched Operation Massachusetts Striker to keep pressure on the PAVN in the southern A Shau Valley. The operation results in 223 PAVN killed and two captured while U.S. losses were 59 killed.
== Professional membership == American Association of Clinical Chemistry (AACC) Academy Fellow of AACC American Society of Clinical Pathology (ASCP) International Society on Thrombosis and Haemostasis (ISTH) Korean Society for Biochemistry and Molecular Biology
Sources: en.wikipedia.org
== Pharmacology == 6-MAM occurs as a metabolite of heroin. Once it has passed first-pass metabolism, 6-MAM is then metabolized into morphine or excreted in urine. Heroin is rapidly metabolized by esterase enzymes in the brain and has an extremely short half-life. It has also relatively weak affinity to μ-opioid receptors because the 3-hydroxy group, essential for effective binding to the receptor, is masked by the acetyl group. Therefore, heroin acts as a prodrug, serving as a lipophilic transporter for the systemic delivery of morphine, which actively binds with μ-opioid receptors.
Selegiline, also known as L-deprenyl and sold under the brand names Eldepryl, Zelapar, and Emsam among others, is a medication which is used in the treatment of Parkinson's disease and major depressive disorder. It has also been studied and used off-label for a variety of other indications, but has not been formally approved for any other use. The medication, in the form licensed for depression, has modest effectiveness for this condition that is similar to that of other antidepressants. Selegiline is provided as a swallowed tablet or capsule or an orally disintegrating tablet (ODT) for Parkinson's disease and as a patch applied to skin for depression. Side effects of selegiline occurring more often than with placebo include insomnia, dry mouth, dizziness, anxiety, abnormal dreams, and application site reactions (with the patch form), among others. At high doses, selegiline has the potential for dangerous food and drug interactions, such as tyramine-related hypertensive crisis (the so-called "cheese reaction") and risk of serotonin syndrome. However, doses within the approved clinical range appear to have little to no risk of these interactions. In addition, the ODT and transdermal patch forms of selegiline have reduced risks of such interactions compared to the conventional oral form. Selegiline has no known misuse potential or dependence liability and is not a controlled substance except in Japan. Selegiline acts as a monoamine oxidase inhibitor (MAOI) and thereby increases levels of monoamine neurotransmitters in the brain.
== Research == Other therapies are under investigation, including gene therapy. BioMarin is conducting clinical trials to investigate PEG-PAL (PEGylated recombinant phenylalanine ammonia lyase or 'PAL'), which is an enzyme substitution therapy in which the missing PAH enzyme is replaced with an analogous enzyme that also breaks down Phe (to ammonia and trans-cinnamic acid). PEG-PAL was in Phase 2 clinical development as of 2015, but was put on clinical hold in September 2021. In February 2022, the FDA issued a statement requiring further data from non-clinical studies to assess oncogenic risk resulting from PEG-PAL treatments.
Alice in Chains released their debut album, Facelift, in August 1990 through Columbia Records. Inspired by the music of Black Sabbath, Deep Purple, and Motörhead, the album was initially unsuccessful; the band's first live performances were local shows and festivals around Seattle. Their first tour came as a supporting act to Extreme for a month. Extreme themselves had yet to reach fame and were playing their first tour; neither band drew well. Alice in Chains followed with an opening slot on a tour with Iggy Pop in November 1990, but the band was similarly received with indifference. Their fortunes began to turn when the video for their breakout single, "Man in the Box", landed regular rotation on MTV, beating Blue Murder for a slot on the channel's "Buzz Bin". With newfound momentum, the group secured two supporting slots on two high-profile tours: first, they were selected to join thrash metal bands Anthrax, Megadeth, and Slayer, on the Clash of the Titans Tour in mid-1991, having replaced opening act Death Angel after the band was involved in a bus accident that left its drummer Andy Galeon critically injured and unable to perform. They were then appointed to a slot on Van Halen's For Unlawful Carnal Knowledge Tour later that year; Van Halen frontman Sammy Hagar personally selected the band. Sales of Facelift increased drastically, and by September 1991, it had been certified gold by the Recording Industry Association of America (RIAA).
== Venom == The venom of the Wagler's pit viper contains four novel peptides (Waglerins 1-4). The Waglerins produce fatal respiratory paralysis of adult mice. An initial study indicated that micromolar concentrations of Waglerin 1 act both pre- and postsynaptically to inhibit transmission across rat neuromuscular junctions. However, Waglerin-1 is a more potent inhibitor of transmission across the mouse neuromuscular junction. A subsequent study demonstrated that Waglerin-1 inhibited the adult mouse endplate response to acetylcholine with an IC50 of 50 nanomolar. In striking contrast, transmission across neuromuscular junctions of neonatal or transgenic mice lacking the adult acetylcholine receptor was not altered by micromolar concentrations of Waglerin-1. Biochemical studies demonstrated that the exquisite selectivity of Waglerin-1 for the adult mouse acetylcholine receptor relies upon several amino acid residues unique to the epsilon subunit of the adult mouse acetylcholine receptor. Waglerin-1's selectivity for the epsilon-subunit containing acetylcholine receptor of adult mice is complemented by selectivity of small peptide toxins purified from the venom of Conus geographus and Conus pergrandis for the gamma-subunit containing acetylcholine receptor of neonatal skeletal muscle. The Waglerins and complementary conotoxins are useful tools to discover the contribution of acetylcholine receptor subunits to synaptogenesis. In addition, study of the Waglerins and related toxic peptides may lead to the discovery of novel molecular targets for drug development.
Sources: en.wikipedia.org
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.
Reported human trials are few, brief and originate mainly from one country. They describe effects on anxiety-related measures, but sample sizes are small and reporting is limited. The results are widely regarded as preliminary rather than confirmed.
Reverse-phase liquid chromatography is used to assess purity and separation of related impurities. Mass spectrometry confirms that the observed molecular mass matches the expected peptide. A certificate of analysis from the supplier is the usual document of record.
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.