If you have been reading about Intranasal route and want a single page that covers the useful parts, this is it: definitions, context, how it is studied, and the questions that come up repeatedly.
Last reviewed on 2025-11-25. Where a claim depends on a specific study, the study is described rather than over-claimed.
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.
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.
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.
Development took place at the Institute of Molecular Genetics of the Russian Academy of Sciences, where a series of short peptides were designed in the 1980s and 1990s. Selank was selected from variants of tuftsin that showed resistance to plasma peptidases. Russian regulatory approval covers it as an anxiolytic agent given intranasally. Outside that market the compound is normally handled as a research chemical rather than a medicine, and no widely recognised international pharmacopoeial monograph exists. The name Selank is a coined trade designation rather than a systematic chemical name.
| Property | Value | Notes |
|---|---|---|
| Typical purity specification | 95 percent or higher by RP-HPLC | Area percentage of the main peak |
| Identity confirmation | Electrospray ionization mass spectrometry | Observed mass compared with the theoretical value near 751.9 Da |
| Recommended dry storage | -20 °C, desiccated | -80 °C for multi-year archival material |
| Solution handling | Prepare fresh; avoid long storage | Sterile filtration reduces microbial load |
| Common synonyms | TKPRPGP; TP-7 | Sequence code and laboratory designation used interchangeably |
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.
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.
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.
=== Transport === Another difference between eukaryotes and prokaryotes is mRNA transport. Because eukaryotic transcription and translation is compartmentally separated, eukaryotic mRNAs must be exported from the nucleus to the cytoplasm—a process that may be regulated by different signaling pathways. Mature mRNAs are recognized by their processed modifications and then exported through the nuclear pore by binding to the cap-binding proteins CBP20 and CBP80, as well as the transcription/export complex (TREX). Multiple mRNA export pathways have been identified in eukaryotes. In spatially complex cells, some mRNAs are transported to particular subcellular destinations. In mature neurons, certain mRNA are transported from the soma to dendrites. One site of mRNA translation is at polyribosomes selectively localized beneath synapses. The mRNA for Arc/Arg3.1 is induced by synaptic activity and localizes selectively near active synapses based on signals generated by NMDA receptors. Other mRNAs also move into dendrites in response to external stimuli, such as β-actin mRNA. For export from the nucleus, actin mRNA associates with ZBP1 and later with 40S subunit. The complex is bound by a motor protein and is transported to the target location (neurite extension) along the cytoskeleton. Eventually ZBP1 is phosphorylated by Src in order for translation to be initiated. In developing neurons, mRNAs are also transported into growing axons and especially growth cones. Many mRNAs are marked with so-called "zip codes", which target their transport to a specific location.
=== Formulations === They may be administered orally or, in some cases, through long-acting (depot) injections administered in the dorsgluteal, ventrogluteal or deltoid muscle. Short-acting parenteral formulations also exist, which are generally reserved for emergencies or when oral administration is otherwise impossible. The oral formulations include immediate release, extended release, and orally disintegrating products (which are not sublingual, and can help ensure that medications are swallowed instead of "cheeked"). Sublingual products (e.g., asenapine) also exist, which must be held under the tongue for absorption. The first transdermal formulation of an antipsychotic (transdermal asenapine, marketed as Secuado), was FDA-approved in 2019.
== Synthesis and production == Reflecting their high stabilities, thiophenes arise from many reactions involving sulfur sources and hydrocarbons, especially unsaturated ones. The first synthesis of thiophene by Meyer, reported the same year that he made his discovery, involves acetylene and elemental sulfur. Thiophenes are classically prepared by the reaction of 1,4-diketones, diesters, or dicarboxylates with sulfidizing reagents such as P4S10 such as in the Paal-Knorr thiophene synthesis. Specialized thiophenes can be synthesized similarly using Lawesson's reagent as the sulfidizing agent, or via the Gewald reaction, which involves the condensation of two esters in the presence of elemental sulfur. Another method is the Volhard–Erdmann cyclization. Thiophene is produced on a modest scale of around 2,000 metric tons per year worldwide. Production involves the vapor phase reaction of a sulfur source, typically carbon disulfide, and a C-4 source, typically butanol. These reagents are contacted with an oxide catalyst at 500–550 °C.
Sources: en.wikipedia.org
=== Influence === Alice in Chains are one of the most popular rock bands from the 1990s. Pantera and Damageplan guitarist Dimebag Darrell had expressed his admiration for Cantrell's guitar work in an interview for Guitar International in 1995, saying that "the layering and the honest feel that Jerry Cantrell gets on [Alice in Chains' Dirt] record is worth a lot more than someone who plays five million notes." Street musician Wesley Willis wrote a song about the band entitled "Alice in Chains", featured on his 1996 album Feel The Power. Billy Corgan revealed that the song "Bleeding The Orchid" from the Smashing Pumpkins' 2007 album Zeitgeist has a bit of a homage to Alice in Chains in the harmonies and was indirectly inspired by the death of Staley. Elton John stated that he is a fan of Alice in Chains and a big admirer of Cantrell. According to Jon Wiederhorn of MTV, Godsmack has "sonically followed Alice in Chains' lead while adding their own distinctive edge." Godsmack singer and founder Sully Erna has also cited Staley as his primary influence. Godsmack was named after the Alice in Chains song "God Smack" from the album Dirt. Staind has covered Alice in Chains' song "Nutshell" live, which appears on the compilation The Singles: 1996-2006, and also wrote a song entitled "Layne", dedicated to Staley, on the album 14 Shades of Grey. Three Days Grace also performs a cover of "Rooster", which can be seen on the DVD Live at the Palace.
Several scandals affected Uribe's administration; the Colombian parapolitics scandal expanded during his second term, involving numerous members of the administration's ruling coalition. Many pro-government lawmakers, such as the President's cousin Mario Uribe, were also investigated for their possible ties to paramilitary organizations. At the end of 2007, FARC agreed to release former senator Consuelo González, politician Clara Rojas, and her son Emmanuel, born in captivity after a relationship with one of her captors. Operation Emmanuel was proposed and set up by Venezuelan President Hugo Chávez, with the permission of the Colombian government. The mission was approved on December 26; however, on December 31, FARC claimed that the hostage release had been delayed because of Colombian military operations. At the same time, Colombian President Álvaro Uribe indicated that FARC had not freed the three hostages because Emmanuel may not be in their hands anymore. Two FARC gunmen were taken prisoner. Colombian authorities added that a boy matching Emmanuel's description had been taken to a hospital in San José del Guaviare in June 2005. The child was in poor condition; one of his arms was hurt, he had severe malnutrition, and he had diseases that are commonly suffered in the jungle. Having been evidently mistreated, the boy was later sent to a foster home in Bogotá, and DNA tests were announced to confirm his identity.
== Z-plasty == This is based upon the principle of mobilizing a full segment of skin from an area to the site needing tissue replacement. The flaps are triangularly shaped opposite each other. It can be used in direct excision and closure of a contracted scar to produce a better looking and healing scar. It helps to elongate and break up a linear scar. It also gives a good result in the release of linear contractures. Z-plasty is of paramount importance to the plastic surgeon and a frequently used method in both single multiple forms.
Sources: en.wikipedia.org
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.
A reported purity value reflects the share of the main peak in one chromatographic run and says nothing about identity. Confirming that the expected sequence is present requires a separate measurement such as mass spectrometry. Purity and identity are distinct questions.
A mass spectrum reports the molecular masses present in a sample and shows whether they match the value expected for selank, near 751.9 Da. It also flags common artifacts such as truncation or adduct formation. It does not establish correct stereochemistry or complete sequence order on its own.
Selank is a seven-amino-acid peptide built from the tuftsin sequence plus a Pro-Gly-Pro tail. It is produced by chemical synthesis rather than extracted from a natural source. The free peptide is usually supplied as a lyophilised powder or in an aqueous formulation.