Research chemical comes up often in conversation and rarely with the context attached. Here we lay out the basics in order, then work through the practical considerations.
Last reviewed on 2026-08-01. Where a claim depends on a specific study, the study is described rather than over-claimed.
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.
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.
Selank is a synthetic heptapeptide developed in Russia as a structural analogue of tuftsin, a naturally occurring immunomodulatory tetrapeptide. Its sequence, Thr-Lys-Pro-Arg-Pro-Gly-Pro, keeps the tuftsin core at the N-terminus and appends a Pro-Gly-Pro tail. Researchers at the Institute of Molecular Genetics in Moscow synthesized the compound during the 1990s while searching for peptides with combined anxiolytic and immunomodulatory activity. The added tail was intended to resist enzymatic cleavage and prolong the molecule's presence in circulation.
| 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 |
Dry powder is normally held at -20 degrees Celsius or lower, in a sealed container with desiccant and protection from light. Reconstituted solutions are usually kept at 2 to 8 degrees Celsius for short periods and frozen for longer ones. Proline residues at several positions are generally associated with some resistance to peptidase attack, but chemical stability still declines at neutral to alkaline pH and at elevated temperature. Exact shelf-life figures are product-specific and are not standardised across suppliers.
Identity and purity are usually assessed by reversed-phase high-performance liquid chromatography, with mass spectrometry used to confirm molecular mass and sequence information. Amino acid analysis and peptide mapping may supplement these methods. Certified reference standards are scarce, and many commercial lots are sold as research chemicals without a pharmacopoeial monograph. Regulatory treatment differs by country: Selank is a registered prescription medicine in Russia, while in the European Union and the United States it is not an approved drug and may fall under research-chemical or unapproved-product frameworks.
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.
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.
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.
Attachment to a host cell. Release of viral genes and possibly enzymes into the host cell. Replication of viral components using host-cell machinery. Assembly of viral components into complete viral particles. Release of viral particles to infect new host cells.
A Penning trap stores charged particles using a strong homogeneous axial magnetic field to confine particles radially and a quadrupole electric field to confine the particles axially. Penning traps are well suited for measurements of the properties of ions and stable charged subatomic particles. Precision studies of the electron magnetic moment by Dehmelt and others are an important topic in modern physics. Penning traps can be used in quantum computation and quantum information processing and are used at CERN to store antimatter. Penning traps form the basis of Fourier-transform ion cyclotron resonance mass spectrometry for determining the mass-to-charge ratio of ions.
==== Metabolism ==== Ritonavir is extensively metabolized by the liver, driven predominantly by the CYP3A enzyme family, with minor contributions from CYP2D6. The biotransformation yields four major metabolites via pathways including N-demethylation, hydroxylation of the isopropyl side chain, and cleavage of the terminal thiazole groups. The primary metabolite is the isopropylthiazole oxidation metabolite (M-2), which retains antiviral activity comparable to the parent drug but circulates at very low plasma concentrations.
== History == The disorder was first described in 1959 by psychiatrist and researcher Albert Stunkard as "night eating syndrome" (NES). The term "binge eating" was coined to describe the same bingeing-type eating behavior but without the exclusive nocturnal component. There is less research on BED than there is on anorexia or bulimia.
===== Nanocubes ===== Silver nanocubes can be synthesized using ethylene glycol as a reducing agent and PVP as a capping agent, in a polyol synthesis reaction (vide supra). A typical synthesis using these reagents involves adding fresh silver nitrate and PVP to a solution of ethylene glycol heated at 140 °C. This procedure can actually be modified to produce another anisotropic silver nanostructure, nanowires, by just allowing the silver nitrate solution to age before using it in the synthesis. By allowing the silver nitrate solution to age, the initial nanostructure formed during the synthesis is slightly different than that obtained with fresh silver nitrate, which influences the growth process, and therefore, the morphology of the final product. Nanorods, Nanobars, and Nanowires Silver nanorods (also categorized as nanobars or nanowires depending on their aspect ratio), are a class of anisotropic nanoparticles extensively studied for their tunable electrical and optical properties. Their morphology is typically controlled by selective capping agents during the synthesis. For instance, polyvinylpyrrodine (PVP) can strongly bind to the {100} facets of silver seeds while interacting more weakly with the {111} facets. This preferential adsorption restricts growth on the {100} surfaces and promotes elongation at the <110> direction, ultimately resulting in the formation of rod-like structures.
Sources: en.wikipedia.org
To ensure that the Presidency of Quito became a part of Gran Colombia and did not remain a collection of small, divided republics, Bolívar sent aid in the form of supplies and an army under Antonio José de Sucre to Guayaquil in February 1821. For a year Sucre was unable to take Quito, and by November both sides, exhausted, signed a ninety-day armistice. The following year, at the Battle of Pichincha on 24 May 1822, Sucre's Venezuelan forces finally conquered Quito; Gran Colombia's hold on the territory was secure. The following year, after a Peruvian Patriot army was destroyed in the Battle of Ica, San Martín met with Simón Bolívar in Guayaquil on 26 and 27 July. Thereafter San Martín decided to retire from the scene. For the next two years, two armies of Rioplatense (Argentinian), Chilean, Colombian and Peruvian Patriots were destroyed trying to penetrate the royalist bastion in the Andean regions of Peru and Upper Peru. A year later a Peruvian congress resolved to make Bolívar head of the Patriot forces in the country. An internecine conflict between La Serna and General Pedro Antonio Olañeta, which was an extension of the Liberal Triennium, proved to be the royalists' undoing. La Serna lost control of half of his best army by the beginning of 1824, giving the Patriots an opportunity.
== Etymology == The name Pakistan was coined by Choudhry Rahmat Ali, a Pakistan Movement activist, who in January 1933 first published it (originally as "Pakstan") in a pamphlet Now or Never, using it as an acronym. Rahmat Ali explained: "It is composed of letters taken from the names of all our homelands, Indian and Asian, Panjab, Afghania, Kashmir, Sindh, and Baluchistan." He added, "Pakistan is both a Persian and Urdu word... It means the land of the Paks, the spiritually pure and clean." Etymologists note that پاک pāk, is 'pure' in Persian and Pashto and the Persian suffix ـستان -stan means 'land' or 'place of'. Rahmat Ali's concept of Pakistan only related to the northwestern area of the Indian subcontinent. He also proposed the name "Banglastan" for the Muslim areas of Bengal and "Osmanistan" for Hyderabad State, as well as a political federation between the three.
Other studies found that, in Tanzania, skin bleaching has been regularly practiced by middle and working classes, as light skin was perceived to facilitate social mobility. Skin whitening practices in several other African countries increased following the onset of independence movements against European colonial rule. Maya Allen attributed this to the increased flow of European products and commercial influence into colonized regions. Several historians have suggested that the increased prevalence of skin whitening in "the Global South" is potentially tied to both precolonial notions of beauty and post-colonial hierarchies of race.
In August 1935, Albert Rowe, secretary of the Tizard Committee, coined the term "Radio Direction and Finding" (RDF), deliberately choosing a name that could be confused with "Radio Direction Finding", a term already in widespread use. In a 9 September 1935 memo, Watson-Watt outlined the progress to date. At that time the range was about 40 mi (64 km), so Watson-Watt suggested building a complete network of stations 20 mi (32 km) apart along the entire east coast. Since the transmitters and receivers were separate, to save development costs he suggested placing a transmitter at every other station. The transmitter signal could be used by a receiver at that site as well as the ones on each side of it. This was quickly rendered moot by the rapid increases in range. When the Committee next visited the site in October, the range was up to 80 mi (130 km), and Wilkins was working on a method for height finding using multiple antennas. In spite of its ad hoc nature and short development time of less than six months, the Orfordness system had already become a useful and practical system. In comparison, the acoustic mirror systems that had been in development for a decade were still limited to only 5 mi (8.0 km) range under most conditions, and were very difficult to use in practice. Work on mirror systems ended, and on 19 December 1935, a £60,000 contract for five RDF stations along the south-east coast was sent out, to be operational by August 1936. The only person not convinced of the utility of RDF was Lindemann.
Sources: en.wikipedia.org
== Signs and symptoms == The symptoms of an episode of diabetic ketoacidosis usually evolve over a period of about 24 hours. Predominant symptoms are nausea and vomiting, pronounced thirst, excessive urine production and abdominal pain that may be severe. In severe DKA, breathing becomes rapid and of a deep, gasping character, called "Kussmaul breathing". The abdomen may be tender to the point that a serious abdominal condition may be suspected, such as acute pancreatitis, appendicitis or gastrointestinal perforation. Vomiting altered blood that resembles coffee grounds occurs in a minority of people and tends to originate from erosion of the esophagus. In severe DKA, there may be confusion or a marked decrease in alertness, including coma. On physical examination there is usually clinical evidence of dehydration, such as a dry mouth and decreased skin turgor. If the dehydration is profound enough to cause a decrease in the circulating blood volume, a rapid heart rate and low blood pressure may be observed. Often, a "ketotic" odor is present, which is often described as "fruity" or "like pear drops". The smell is due to the presence of acetone. If Kussmaul respiration is present, this is reflected in an increased respiratory rate. Small children with DKA are relatively prone to brain swelling, also called cerebral edema, which may cause headache, coma, loss of the pupillary light reflex, and can progress to death. It occurs in about 1 out of 100 children with DKA and more rarely occurs in adults.
(WINNER) The contestant won the whole competition. ‡ The contestant won the Pre-Heat challenge. (WIN) The contestant won the Main Heat challenge. (HIGH) The contestant had one of the best dishes for that week. (IN) The contestant performed well enough to move on to the next week. (LOW) The contestant had one of the bottom dishes for that week, but was not eliminated. (OUT) The contestant was eliminated for worst dish.
== Advertising == The company owns two blimps: the Bloomin' Onions I and II, both named after their appetizer. For several years, the company ran a media campaign with an Australian-themed variation of the Of Montreal composition "Wraith Pinned to the Mist (And Other Games)." General (Ret) Tommy Franks sits on the Board Of Directors for OSI Restaurant Partners, INC., which owns Outback Steakhouse.
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.
Selank is a synthetic seven-amino-acid peptide modeled on tuftsin, a fragment of the immunoglobulin G heavy chain. It was designed in Russia to combine anxiolytic and immunomodulatory properties in one molecule.