A practical reference on batch purity: what it is, how it behaves, what the literature reports, and where the honest uncertainties sit.
Reviewed 2026-01-27. Anything still debated is marked as such rather than presented as settled.
Regulatory treatment varies by jurisdiction. In Russia the compound is a registered prescription product, while in the European Union and the United States it is generally handled as a research chemical without a marketing authorization. Suppliers therefore operate outside pharmaceutical oversight, and buyers rely on supplier documentation for purity and identity claims. Chain of custody and third-party testing are the main verification tools. Analysts note that the absence of a pharmacopoeial monograph for research-grade material limits standardization across vendors.
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.
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.
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.
| Property | Value | Notes |
|---|---|---|
| Typical purity report | 95% or higher by HPLC | Area percentage at 214 nm |
| Identity confirmation | Mass spectrometry | Electrospray or MALDI |
| Powder storage | -20 C, desiccated | Protect from light |
| Solution storage | 2-8 C short term | Freeze aliquots for longer |
| Quality document | Certificate of analysis | States method and value |
Peptide bonds are vulnerable to protease attack, and Selank is no exception. Measured half-life in serum is short, on the order of minutes in several reports, which explains why intranasal administration is the common route described in the literature. Absorption across the nasal mucosa partially bypasses first-pass hepatic metabolism. Quantitative data on human bioavailability remain limited and are difficult to compare across studies.
Lyophilised material kept dry at minus 20 degrees Celsius or colder is the most stable form, and suppliers commonly state a shelf life of two years or more under those conditions. Once dissolved, degradation accelerates through hydrolysis and deamidation, particularly at alkaline pH or elevated temperature. Working solutions are usually divided into single-use aliquots to avoid repeated freeze-thaw cycles. The choice of reconstitution solvent affects both stability and the ionic strength of the final preparation.
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.
Published clinical work is concentrated in Russian-language journals and generally involves small samples without independent replication. Systematic reviews in English note the shortage of randomised, placebo-controlled trials and the difficulty of verifying methods from translated reports. Outcome measures vary between studies, which complicates pooling of results. Interest in the compound as a cognitive or anxiolytic agent therefore rests on a thinner evidence base than the volume of citations suggests. Replication in well-powered trials with preregistered endpoints would be needed before firm conclusions about efficacy can be drawn.
Proposed mechanisms centre on the GABAergic system. Animal and tissue studies report changes in GABA-A receptor expression and reduced activity of GABA transaminase, the enzyme that degrades GABA. Effects on monoamine turnover, including serotonin and dopamine pathways, are also described, and a separate line of work links the peptide to increased expression of brain-derived neurotrophic factor in hippocampal tissue. Most of these findings come from rodent models and cell preparations. How the individual observations combine into a single coherent mode of action is not settled.
Peptide stability depends strongly on temperature, moisture, and pH. Lyophilized Selank is generally most stable when stored cold and dry, with freezer temperatures commonly used for long-term storage. In solution, the compound is susceptible to hydrolysis and to microbial growth if it is not handled aseptically. The C-terminal proline-rich extension appears to slow enzymatic cleavage relative to tuftsin, though quantitative degradation rates vary with the matrix and the conditions tested. Published stability data specific to Selank remain sparse.
Quality assessment of Selank samples typically combines purity determination with identity confirmation and counter-ion analysis. Purity is usually reported as a percentage by chromatographic area, with values above 95 percent often quoted for research-grade material. Water content and residual solvents are checked in lyophilized batches because they affect both stability and accurate mass determination. A reported purity figure does not by itself establish that a sample is the intended sequence, so orthogonal methods are needed to rule out sequence isomers or truncation products.
=== Extensions === The area under the effect curve (AUEC) is an integral of the effect of a drug over time, estimated as a previously-established function of concentration. It was proposed to be used instead of AUC in animal-to-human dose translation, as computer simulation shows that it could cope better with half-life and dosing schedule variations than AUC. This is an example of a PK/PD model, which combines pharmacokinetics and pharmacodynamics.
Carlton – The rivalry between Essendon and Carlton is considered one of the strongest in the league. With the teams sharing the record of 16 premierships, both sides are keen to become outright leader, or if out of the finals race, at least ensure the other doesn't. In recent years, the rivalry has thickened, with Carlton beating the 1999 Minor Premiers and premiership favourites by 1 point in the Preliminary Final. Other notable meetings between the two clubs include the 1908, 1947, 1949, 1962 and 1968 VFL Grand Finals and 1993 AFL Grand Final, with some decided by small margins. Of the 6 Grand Finals played out of the two clubs, Essendon has won 3 and Carlton has won 3. Collingwood – In the early days of the VFL, this rivalry grew out of several Grand Final meetings: 1901, 1902 and 1911. The teams didn't meet again in a Grand Final until 1990 when Collingwood won to draw level with the Bombers on 14 premierships and deny the Bombers a chance to join Carlton with 15 flags. Since 1995, the clubs face off against each other annually in the Anzac Day clash, a match which is described as the second biggest of the season (behind only the Grand Final). Being possibly the two biggest football clubs in Victoria, regardless of their position on the ladder, this game always attracts a huge crowd, and it is a match both teams have a great desire to win regardless of either team's season prospects. The rivalry thickened further in 2023 when Collingwood joined Essendon and Carlton with a record 16 premierships.
== Efficacy == There is no clear measure of the effectiveness of the war on drugs, and it has been widely called a policy failure. Thirty years into the campaign, a National Research Council report, "Informing America's Policy on Illegal Drugs" (2001), found that "existing drug-use monitoring systems are strikingly inadequate to support the full range of policy decisions that the nation must make." The report noted that studies of efforts to address drug usage and smuggling, from US military operations to eradicate coca fields in Colombia, to domestic drug treatment centers, had all been inconclusive, if the programs had been evaluated at all: It concluded, "It is unconscionable for this country to continue to carry out a public policy of this magnitude and cost without any way of knowing whether and to what extent it is having the desired effect." Writing in the New Statesmen in 2021, journalist James Bloodworth stated, "The war on drugs is a failure. We know this. We've long known it. In fact, there is such an abundance of evidence for its failure that we have more certainty here than in most areas of policy. ... According to the International Drug Policy Consortium there was a 31 per cent global increase in drug taking between 2011 and 2016. ...
AB + e− → A− + B+ + e− Calibration of the mass spectrometer is important in electron capture ionization mode. A calibration compound is needed to ensure reproducibility in EC-MS. It is used to ensure that the mass scale used is correct and that the groups of ions are constant on a regular basis. Fragmentation in ECI has been studied by tandem mass spectrometry. The technique can be used with gas chromatography-mass spectrometry.
=== Control of the oxygen reduction potential === Spoilage bacteria and lipid oxidation usually need oxygen, so reducing the oxygen around fish can increase shelf life. This is done by controlling or modifying the atmosphere around the fish, or by vacuum packaging. Controlled or modified atmospheres have specific combinations of oxygen, carbon dioxide and nitrogen, and the method is often combined with refrigeration for more effective fish preservation.
Sources: en.wikipedia.org
=== Highway safety === Safety grooving, the cutting of grooves in concrete to increase traction and prevent injury, was first developed to reduce aircraft accidents on wet runways. Represented by the International Grooving and Grinding Association, the industry expanded into highway and pedestrian applications. Safety grooving originated at Langley Research Center, which assisted in testing the grooving at airports and on highways. Skidding was reduced, stopping distance decreased, and a vehicle's cornering ability on curves was increased. The process has been extended to animal holding pens, parking lots, and other potentially slippery surfaces.
The Turkish and Persian people were the first to cultivate tulips. While the cultivation of tulips in Iranian gardens dates back to the 10th century, the westward expansion of diverse tulip varieties into Asia Minor occurred most significantly under the Seljuk dynasty. The Persian poet Omar Khayyam's 11th-century poetry frequently featured the tulip as a symbol of ideal feminine beauty. Early cultivars must have emerged from hybridisation in gardens from wild collected plants, which were then favoured, possibly due to flower size or growth vigour. The tulip is not mentioned by any writer from antiquity, therefore it seems probable that tulips were introduced into Anatolia only with the advance of the Seljuks. In the Ottoman Empire, numerous types of tulips were cultivated and bred, and today, 14 species can still be found in Turkey. Tulips are mentioned by the 13th century Persian sufi mystic Jalāl ad-Dīn Rûmi. Species of tulips in Turkey typically come in red, less commonly in white or yellow. The Ottoman Turks had discovered that these wild tulips were great changelings, freely hybridising (though it takes 7 years to show colour) but also subject to mutations that produced spontaneous changes in form and colour. A paper by Arthur Baker reports that in 1574, Sultan Selim II ordered the Kadi of A'azāz in Syria to send him 50,000 tulip bulbs. However, John Harvey points out several problems with this source, and there is also the possibility that tulips and hyacinth (sümbüll), originally Indian spikenard (Nardostachys jatamansi) have been confused.
=== Outside Greece === Although frappés are commonly associated with Greece, their popularity has grown in other nations in the recent years. Frappés first became broadly known outside of Greece during the 2004 Summer Olympics in Athens, wherein many tourists became fond of them and an article was published in the Los Angeles Times. Immigrants and tourists in Greece have also helped to take the frappé abroad.
== Research and pipeline == In 2025, Novo tested whether semaglutide helped slow progression for Alzheimer's disease. However, on November 24, 2025, the company announced that the studies failed to find any effect of the drug on cognition and functioning in people with mild cognitive impairment or with dementia. Novo was researching pulmonary delivery systems for diabetic medications, and in the early stages of research into autoimmune and chronic inflammatory diseases, using technologies such as translational immunology and monoclonal antibodies. In September 2014, the company announced a decision to discontinue all research in inflammatory disorders, including the discontinuation of R&D in anti-IL-20 for the treatment of rheumatoid arthritis. In September 2018, it was reported that the company would lay off 400 administrative staff, laboratory technicians and scientists, in Denmark and China in order to concentrate research and development efforts on "transformational biological and technological innovation".
Sources: en.wikipedia.org
Purity is usually reported as an HPLC area percentage, most often measured at 214 nm. Identity is confirmed separately by mass spectrometry. A certificate of analysis should state both the method and the observed value.
Dry powder is kept frozen, desiccated, and shielded from light. Dissolved material is aliquoted and frozen to limit freeze-thaw cycles. Short-term refrigerated storage is common for working solutions.
Russia registers it as a prescription nasal product. Most other markets classify it as a research chemical with no approved medical use. Oversight of purity and labeling is consequently minimal in those markets.
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.