If you have been reading about reverse-phase HPLC 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 2026-01-04. Where a claim depends on a specific study, the study is described rather than over-claimed.
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.
Naming conventions place Selank in the same research family as Semax, another Russian-developed peptide investigated for cognitive effects. The two compounds share a lineage but differ in sequence and in the biological systems proposed as their targets. Semax descends from ACTH fragments, whereas Selank descends from tuftsin. Publications sometimes identify Selank by its full peptide sequence or by laboratory codes rather than one uniform trade name. Because replication outside Russia is limited, reports on its properties are best read alongside the study design and the purity of the material tested.
Selank is a synthetic heptapeptide developed in Russia during the 1990s. Researchers at the Institute of Molecular Genetics of the Russian Academy of Sciences designed it as a stabilized analog of tuftsin, a naturally occurring immunomodulatory tetrapeptide. The compound has been studied primarily for its reported anxiolytic and nootropic effects. It remains largely unknown in Western pharmacology and is not approved as a medicine by major regulators such as the FDA or the EMA.
The primary structure of Selank is Thr-Lys-Pro-Arg-Pro-Gly-Pro, corresponding to the molecular formula C33H57N11O9 and a monoisotopic mass of roughly 751.9 daltons. The N-terminal threonine and the arginine residue in the fourth position are shared with tuftsin, which carries the sequence Thr-Lys-Pro-Arg. The three additional residues at the C-terminus, Pro-Gly-Pro, extend the chain and are associated with greater resistance to enzymatic degradation. This extension also separates Selank from the shorter parent peptide.
| Property | Value | Notes |
|---|---|---|
| Molecular formula | C33H57N11O9 | Derived from the seven-residue sequence |
| Molecular weight | About 751.9 g/mol | Average mass; the monoisotopic value is slightly lower |
| Residue count | Seven amino acids | Thr-Lys-Pro-Arg-Pro-Gly-Pro |
| Parent compound | Tuftsin (Thr-Lys-Pro-Arg) | Selank extends tuftsin at the C-terminus |
| Compound class | Synthetic short peptide | Studied in a research setting; not a licensed drug in most markets |
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.
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.
Purity assessment relies mainly on reverse-phase high-performance liquid chromatography with ultraviolet detection. Because the peptide lacks a strong chromophore, detection often uses backbone absorbance near 214 nm. Identity is confirmed by mass spectrometry, typically electrospray ionization or matrix-assisted laser desorption, comparing the measured mass against the expected value. Amino acid analysis can verify composition after acid hydrolysis. Diastereomer content and residual counterions are reported less often, although both can influence biological assays.
Lyophilized material is generally stable for extended periods when kept dry at or below minus twenty degrees Celsius. Working solutions are less stable, and common practice is to aliquot and freeze them so that repeated freeze-thaw cycles are avoided. Aqueous solutions are sensitive to pH extremes and to microbial growth, so short-term storage at refrigerator temperature is typical. Oxidation and hydrolysis are the principal degradation routes. Reconstitution with sterile water or a mild buffer is standard, and solutions should be protected from light.
=== Brand names === It is marketed under several brand names, including, Brozam, Lectopam, Lexomil, Lexotan, Lexilium, Lexaurin, Brazepam, Rekotnil, Bromaze, Somalium, Lexatin, Calmepam, Zepam and Lexotanil.
=== Senate Foreign Relations Committee === Biden was a longtime member of the Senate Foreign Relations Committee. He became its ranking minority member in 1997, and chaired it from June 2001 to 2003 and 2007 to 2009. His positions were generally liberal internationalist. He collaborated effectively with Republicans and sometimes went against elements of his own party. During this time he met with at least 150 leaders from 60 countries and international organizations, becoming a well-known Democratic voice on foreign policy. Biden voted against authorization for the Gulf War in 1991. He became interested in the Yugoslav Wars after hearing about Serbian abuses during the Croatian War of Independence in 1991. Once the Bosnian War broke out, Biden was among the first to call for the "lift and strike" policy. George H. W. Bush and Bill Clinton were both reluctant to implement the policy, fearing Balkan entanglement. In April 1993, Biden had a tense three-hour meeting with Serbian leader Slobodan Milošević. Biden worked on several versions of legislative language urging the U.S. toward greater involvement. He has called his role in affecting Balkan policy in the mid-1990s his "proudest moment in public life" related to foreign policy. In 1999, during the Kosovo War, Biden supported the NATO bombing of Yugoslavia. He and Senator John McCain co-sponsored the McCain-Biden Kosovo Resolution, which called on Clinton to use all necessary force, including ground troops, to confront Milošević over Yugoslav actions toward Kosovo Albanians.
=== Medical illness === Cushing's syndrome (a condition in which the body contains excess amounts of cortisol) may also influence childhood obesity. Researchers analyzed two isoforms (proteins that have the same purpose as other proteins, but are programmed by different genes) in the cells of 16 adults undergoing abdominal surgery. They discovered that one type of isoform created oxo-reductase activity (the alteration of cortisone to cortisol) and this activity increased 127.5 pmol mg sup when the other type of isoform was treated with cortisol and insulin. The activity of the cortisol and insulin can possibly activate Cushing's syndrome. Hypothyroidism is a hormonal cause of obesity, but it does not significantly affect obese people who have it more than obese people who do not have it. In a comparison of 108 obese patients with hypothyroidism to 131 obese patients without hypothyroidism, researchers discovered that those with hypothyroidism had only 0.077 points more on the caloric intake scale than did those without hypothyroidism.
Nickel allergy is any of several allergic conditions provoked by exposure to the chemical element nickel. Nickel allergy often takes the form of nickel allergic contact dermatitis (Ni-ACD), a form of allergic contact dermatitis (ACD). Ni-ACD typically causes a rash that is red and itchy and that may be bumpy or scaly. The main treatment for it is avoiding contact with nickel-releasing metals, such as inexpensive jewelry. Another form of nickel allergy is a systemic form: systemic nickel allergy syndrome (SNAS) can mimic some of the symptoms of irritable bowel syndrome (IBS) and also has a dermatologic component.
Specifically, the complex of TAP, tapasin, MHS Class 1, ERp57, and calreticulin is called the peptide-loading complex (PLC). Peptides are loaded to MHC-I peptide binding groove between two alpha helices at the bottom of the α1 and α2 domains of the MHC class I molecule. After releasing from tapasin, peptide-MHC-I complexes (pMHC-I) exit the ER and are transported to the cell surface by exocytic vesicles. Naïve anti-viral T cells (CD8+) cannot directly eliminate transformed or infected cells. They have to be activated by the pMHC-I complexes of antigen-presenting cells (APCs). Here, antigen can be presented directly (as described above) or indirectly (cross-presentation) from virus-infected and non-infected cells. After the interaction between pMHC-I and TCR, in presence of co-stimulatory signals and/or cytokines, T cells are activated, migrate to the peripheral tissues and kill the target cells (infected or damaged cells) by inducing cytotoxicity. Cross-presentation is a special case in which MHC-I molecules are able to present extracellular antigens, usually displayed only by MHC-II molecules. This ability appears in several APCs, mainly plasmacytoid dendritic cells in tissues that stimulate CD8+ T cells directly. This process is essential when APCs are not directly infected, triggering local antiviral and anti-tumor immune responses immediately without trafficking the APCs in the local lymph nodes.
Sources: en.wikipedia.org
Misdiagnoses can lead physicians to order biopsies, potentially exacerbating the growth of FOP bone. The presence of malformed toes or thumbs in those born with FOP helps distinguish this disorder from other skeletal problems. With proper medical management the median age of survival is 40 years. However, delayed diagnosis, trauma, and infections can decrease life expectancy.
===== Organic oxidation methods for TOC analysis ===== Oxidation of organics to CO2 is most commonly achieved in liquid solutions by the creation of the highly oxidizing chemical species, the hydroxyl radical (OH•). Organic oxidation in a combustion environment involves the creation of other energized molecular oxygen species. For the typical TOC levels in UPW systems most methods utilize hydroxyl radicals in the liquid phase. There are multiple methods to create sufficient concentrations of hydroxyl radicals needed to completely oxidize the organics in water to CO2, each method being appropriate for different water purity levels. For typical raw waters feeding into the front end of an UPW purification system the raw water can contain TOC levels between 0.7 mg/L to 15 mg/L and require a robust oxidation method that can ensure there is enough oxygen available to completely convert all the carbon atoms in the organic molecules into CO2. Robust oxidation methods that supply sufficient oxygen include the following methods; Ultraviolet light (UV) & persulfate, heated persulfate, combustion, and super critical oxidation. Typical equations showing persulfate generation of hydroxyl radicals follows. S2O2−8 + hν (254 nm) → 2 SO−4• and SO−4 • + H2O → HSO−4 + OH • When the organic concentration is less than 1 mg/L as TOC and the water is saturated with oxygen UV light is sufficient to oxidize the organics to CO2, this is a simpler oxidation method.
== Further reading == Notes for guidance on the clinical administration of radiopharmaceuticals and use of sealed radioactive sources. Administration of radioactive substances advisory committee. March 2006. Produced by the Health Protection Agency. Malabsorption. In: The Merck Manual of Geriatrics, chapter 111. Leukoscan summary of product characteristics (Tc99m-Sulesomab). Schwochau, Klaus. Technetium. Wiley-VCH (2000). ISBN 3-527-29496-1
== Purpose == The purpose of the NPU terminology is to enable patient examination data to be safely transmitted between laboratory information systems, recognized, compared, reused in calculations, extracted for research or statistics, and stored for documentation, without loss of meaning. It does not cover sampling procedures or methodologies used for determining these data, which may both vary over time. The terminology adheres to international standards of metrology, terminology, and health informatics, in particular the International System of Quantities (ISQ) and the International Systems of Units (SI units). It currently includes over 17 000 entries widely covering multiple disciplines in the field of clinical laboratory science including:
Sources: en.wikipedia.org
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.
Tuftsin contains four residues, while selank carries an additional Pro-Gly-Pro segment at the carboxyl end. That extension is intended to reduce enzymatic cleavage. Comparative pharmacokinetic data in humans remain limited.
No single receptor target is widely accepted as the definitive mediator of the reported effects. Proposed contributors include GABAergic modulation, shifts in monoamine turnover, and altered neuropeptide degradation. The mechanism is treated in the literature as unresolved.
Selank is a synthetic heptapeptide designed as a stabilized analog of the natural tetrapeptide tuftsin. It has been investigated mainly for anxiolytic and cognitive effects. It is not an approved pharmaceutical in most countries.