Everything below concerns Semax. We keep the language plain, cite what the science says, and separate well-supported claims from open questions.
Updated 2026-03-23. Numbers and descriptions here follow the published literature rather than marketing material.
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.
Peptide bonds in selank are susceptible to hydrolysis under strongly acidic or basic conditions, and the terminal proline residues are vulnerable to exopeptidase activity in biological samples. Lyophilized powder stored dry at -20 °C typically remains stable for extended periods, whereas aqueous solutions degrade faster and may lose measurable purity within days to weeks depending on pH, temperature, and microbial load. Repeated freeze-thaw cycles promote aggregation and adsorption to container surfaces. For analytical work, solutions are usually prepared fresh, kept cold, and used within a single working day.
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.
Selank is a synthetic heptapeptide with the sequence Thr-Lys-Pro-Arg-Pro-Gly-Pro. It was designed as a stabilized analogue of tuftsin, a naturally occurring tetrapeptide fragment derived from the immunoglobulin heavy chain. The additional Pro-Gly-Pro segment at the carboxyl terminus is intended to slow enzymatic cleavage. The compound is usually described in the literature as a synthetic peptide with anxiolytic and cognitive-related activity, a label that reflects a research context rather than an approved therapeutic category.
Most published work on selank originates from a small number of research groups in the Russian Federation. A large share of that record appears in Russian-language journals, which limits access for readers who rely on English-indexed databases. Independent replication by laboratories outside the original research network is sparse in publicly available sources. This concentration of origin and language is a frequently noted feature when the compound is summarized in broader reviews of synthetic peptides.
Reported pharmacological effects center on reduced anxiety-like behavior in animal models and on measures of memory and learning. Proposed contributing mechanisms include modulation of GABAergic signaling, shifts in monoamine turnover, and changes in the activity of enzymes that degrade neuropeptides. Effects on the expression of genes linked to neuroplasticity have also been described. No single molecular target is widely accepted, and whether the behavioral findings arise from one pathway or several remains an open question.
| Property | Value | Notes |
|---|---|---|
| Identity confirmation | Reversed-phase HPLC retention time versus reference standard | Retention depends on column, gradient, and ion-pairing agent |
| Mass confirmation | Electrospray or MALDI mass spectrometry | Doubly protonated ion near m/z 377 is consistent with about 752 Da |
| Typical purity specification | 95 percent or higher by chromatographic peak area | Lower values suggest truncated or modified peptide species |
| Storage of lyophilized powder | -20 °C, desiccated, protected from light | Powder tolerates long storage better than solution |
| Storage of solution | 2-8 °C for short periods | Freeze-thaw cycling promotes aggregation and surface adsorption |
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.
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.
=== Hepatotoxicity === Moderate to severe acute hepatitis has occurred in several adults who had been taking the drug at the recommended dose for two to four weeks. Plasma rosiglitazone concentrations may be increased in people with existing liver problems.
== Natural extract == Combretum indicum (Quisqualis indica var. villosa) is native to tropical Asia but is still doubt whether is indigenous from Africa or was introduced there. Since the amino acid that can be isolated from its fruits can nowadays be made in the lab, the plant is mostly cultivated as an ornamental plant. In natural medicine tradition Quisqualis indica has an anthelmintic effect, therefore they are used to treat round worm infection. Quisqualic acid resembles the action of the anthelmintic α-santonin, so in some countries the seeds of the plants are used to substitute for the drug. However, the acid has shown excitatory effects on cultured neurons, as well as in a variety of animal models, as it causes several types of limbic seizures and neuronal necrosis. The quisqualic acid can be now commercially synthesized, and it functions as an antagonist for its receptor, found in the mammalian central nervous system.
=== Pharmacokinetics === Ketamine can be absorbed by many different routes due to its water and lipid solubility. Intravenous ketamine bioavailability is 100% by definition, intramuscular injection bioavailability is slightly lower at 93%, and epidural bioavailability is 77%. Subcutaneous bioavailability has never been measured but is presumed to be high. Among the less invasive routes, the intranasal route has the highest bioavailability (45–50%) and oral – the lowest (16–20%). Sublingual and rectal bioavailabilities are intermediate at approximately 25–50%. After absorption ketamine is rapidly distributed into the brain and other tissues. The plasma protein binding of ketamine is variable at 23–47%.
Sources: en.wikipedia.org
== External links == GeneReviews/NCBI/NIH/UW entry on Hemophilia A Factor+VIII at the U.S. National Library of Medicine Medical Subject Headings (MeSH) Overview of all the structural information available in the PDB for UniProt: P00451 (Human Factor VIII) at the PDBe-KB.
Illustrated and well defined chemistry lab practical on ion exchange from Dartmouth College Some applets illustrating ion exchange processes A simple explanation of deionization Ion exchange, BioMineWiki Archived 2020-08-11 at the Wayback Machine
Acrosin is a digestive enzyme that acts as a protease. In humans, acrosin is encoded by the ACR gene. Acrosin is released from the acrosome of spermatozoa as a consequence of the acrosome reaction. It aids in the penetration of the Zona Pellucida.
==== Post-war foreign aid ==== Point Four and TCA had been established in the context of several other programs in the large-scale U.S. foreign aid effort of the 1940s. Already during the war, in 1943, the U.S. (jointly with its wartime allies, referred to collectively as "the United Nations") established the "United Nations Relief and Rehabilitation Administration" (UNRRA) for war-affected parts of Europe, China, the Philippines, Korea, and Ethiopia. Immediately after the war, the United States government supplied relief in Germany and Japan, funded by appropriations for "Government and Relief in Occupied Areas" (GARIOA). Relief was quickly followed by reconstruction assistance. In 1946, the U.S. created a special financial-assistance program for rehabilitation of war damages in its former possession, the Philippines. In 1948, reconstruction assistance was expanded through the Marshall Plan, implemented by the Economic Cooperation Administration (ECA), mainly for Western Europe. In the same year, the U.S. and China established the Joint Commission on Rural Reconstruction, which, starting on the mainland and continuing for two decades in Taiwan, provided sustained development assistance. Also, the Fulbright Program of academic exchanges was established in 1946, globalizing the wartime program of exchange visits between professionals from Latin America and the United States. In contrast to the Marshall Plan, Point Four focussed on technical assistance and provided financial assistance only in limited amounts to support its technical initiatives.
Sources: en.wikipedia.org
== Applications == Acetonitrile is used mainly as a solvent in the purification of butadiene in refineries. Specifically, acetonitrile is fed into the top of a distillation column filled with hydrocarbons including butadiene, and as the acetonitrile falls down through the column, it absorbs the butadiene which is then sent from the bottom of the tower to a second separating tower. Heat is then employed in the separating tower to separate the butadiene. In the laboratory, it is used as a medium-polarity non-protic solvent that is miscible with water and a range of organic solvents, but not saturated hydrocarbons. It has a convenient range of temperatures at which it is a liquid, and dissolves a wide range of ionic and nonpolar compounds and is useful as a mobile phase in HPLC and LC–MS. It is widely used in battery applications because of its relatively high dielectric constant and ability to dissolve electrolytes. For similar reasons, it is a popular solvent in cyclic voltammetry. Its ultraviolet transparency UV cutoff, low viscosity and low chemical reactivity make it a popular choice for high-performance liquid chromatography (HPLC). Acetonitrile plays a significant role as the dominant solvent used in oligonucleotide synthesis from nucleoside phosphoramidites. Industrially, it is used as a solvent for the manufacture of pharmaceuticals and photographic film.
=== 1994–1996: Nagoya Grampus Eight === Shortly after his dismissal, Wenger travelled to the United Arab Emirates to attend a series of conferences held by FIFA. Wenger was a member of the football governing body's technical committee, responsible for analysing the 1994 World Cup, and made a presentation to coaches of emerging football nations. His speech was closely followed by Japanese delegates, whose country had invested millions into the restructuring of its football league system. Representatives of Toyota, the majority owner of Nagoya Grampus Eight soon met with Wenger and offered him the chance to become the club's manager. Wenger deliberated, even though the idea of working abroad appealed to him; negotiations between the two parties lasted for two months. In that time, he sought the advice of his closest friends and family, and flew to Japan to watch Nagoya Grampus' striker Gary Lineker make his final appearance before his professional retirement. In December 1994, Wenger agreed to become manager of Nagoya Grampus, on a two-year contract worth ¥75m annually.
Like all governing institutions in mainland China, Ningxia has a parallel party-government system, in which the CCP Ningxia Regional Committee secretary outranks the government chairman. The CCP Ningxia Regional Committee acts as the top policy-formulation body, and has control over the Ningxia Hui Autonomous Region People's Government.
Sources: en.wikipedia.org
Identity is confirmed by matching the retention time in reversed-phase chromatography against a reference standard and by measuring the molecular mass with mass spectrometry. Tandem mass spectrometry or amino acid analysis can verify the sequence of the seven residues. Because the peptide contains no aromatic amino acids, detection at 280 nm is not useful.
Lyophilized powder is normally stored desiccated at -20 °C, protected from light and moisture. Powder kept under these conditions is generally stable for long periods. Solutions are less stable and are usually prepared immediately before use.
A purity value from one chromatographic method does not capture every possible impurity. Related peptides with similar retention behavior, counterions, and residual solvents may not appear in the same analysis. Independent testing with an orthogonal method provides stronger assurance of identity and content.
Selank is a synthetic heptapeptide with the sequence Thr-Lys-Pro-Arg-Pro-Gly-Pro, designed as a metabolically stabilized analogue of the endogenous tetrapeptide tuftsin. It has been studied mainly against anxiety-related and cognitive endpoints rather than as an approved medicine in most jurisdictions.