Selank raises a handful of sensible questions. This page answers them in order, starting with the fundamentals and moving to applications.
Reviewed 2025-09-28. Anything still debated is marked as such rather than presented as settled.
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.
Enzymatic stability motivates the extra three residues at the carboxyl end. Native tuftsin is cleaved quickly by circulating aminopeptidases and carboxypeptidases, which limits its duration of action and its usefulness as a tool compound. Extending the chain with proline-rich segments is a common design tactic because proline constrains the backbone and slows proteolysis. The same Pro-Gly-Pro motif appears in other Russian-developed peptides of the era. Whether the full seven-residue chain is required for activity, or whether it acts mainly as a prodrug releasing tuftsin, remains unresolved.
Selank is a hydrophilic peptide and dissolves readily in water and in aqueous buffers. The lyophilised powder is typically a white to off-white solid. Because short peptides are prone to hydrolysis and oxidation, handling benefits from limiting exposure to heat, moisture and strong light. Working solutions are commonly prepared in sterile water or saline, and repeated freeze-thaw cycles are avoided to reduce aggregation and loss of activity. These practices reflect general laboratory convention rather than published stability specifications.
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.
| Property | Value | Notes |
|---|---|---|
| Chemical class | Synthetic heptapeptide | Tuftsin analogue with a C-terminal Pro-Gly-Pro tail |
| Amino acid sequence | Thr-Lys-Pro-Arg-Pro-Gly-Pro | Abbreviated TKPRPGP in most catalogues |
| Molecular mass | About 752 Da | Value for the free peptide |
| Solubility | Freely soluble in water | Aqueous solutions are kept cold and used promptly |
| Typical storage | -20 °C, dry, protected from light | Applies to the lyophilised powder before reconstitution |
Proposed mechanisms centre on modulation of the GABAergic system, with reports of altered expression of genes related to GABA-A receptor subunits and changed monoamine turnover. Some studies describe inhibition of enkephalinase, the enzyme that degrades endogenous enkephalins, which may prolong opioid peptide signalling. Effects on brain-derived neurotrophic factor and on cytokine expression have also been reported. These findings come largely from animal models and small human studies, and the precise primary target remains unresolved.
Published clinical evidence is limited. Most controlled trials were conducted in Russia, enrolled modest numbers of participants, and appeared in Russian-language journals, which restricts independent verification. Reported outcomes include lower anxiety scores, improved attention and memory measures, and changes in fatigue ratings. Reviews written in English note methodological limitations such as small samples and inconsistent endpoints. Whether the compound produces clinically meaningful benefit relative to established anxiolytics is therefore an open question rather than an established finding.
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.
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.
LMNA missense mutation (c.1580G>T) introduced at LMNA gene – position 1580 (nt) in the DNA sequence (CGT) causing the guanine to be replaced with the thymine, yielding CTT in the DNA sequence. This results at the protein level in the replacement of the arginine by the leucine at the position 527. This leads to destruction of salt bridge and structure destabilization. At phenotype level this manifests with overlapping mandibuloacral dysplasia and progeria syndrome. The resulting transcript and protein product is:
A study to compare the results of people taking a new treatment with the results of people taking the standard treatment (for example, which group has better survival rates or fewer side effects). In most cases, studies move into phase III only after a treatment seems to work in phases I and II. Phase III trials may include hundreds of people. (NCI) Expanded controlled and uncontrolled trials after preliminary evidence suggesting effectiveness of the drug has been obtained, and are intended to gather additional information to evaluate the overall benefit-risk relationship of the drug and provide and adequate basis for physician labeling. (NLM) Phase 3 studies are expanded controlled and uncontrolled trials. They are performed after preliminary evidence suggesting effectiveness of the drug has been obtained, and are intended to gather the additional information about effectiveness and safety that is needed to evaluate the overall benefit-risk relationship of the drug and to provide an adequate basis for physician labeling. Phase 3 studies usually include from several hundred to several thousand subjects. (21CFR312) Phase IV clinical trial
=== North America === Soybeans were first introduced to North America from China in 1765, by Samuel Bowen, a former East India Company sailor who had visited China in conjunction with James Flint, the first Englishman legally permitted by the Chinese authorities to learn Chinese. The first "New World" soybean crop was grown on Skidaway Island, Georgia, in 1765 by Henry Yonge from seeds given him by Samuel Bowen. Bowen grew soy near Savannah, Georgia, possibly using funds from Flint, and made soy sauce for sale to England. Although soybean was introduced into North America in 1765, for the next 155 years, the crop was grown primarily for forage. In 1831, the first soy product "a few dozen India Soy" [sauce] arrived in Canada. Soybeans were probably first cultivated in Canada by 1855, and definitely in 1895 at Ontario Agricultural College. It was not until Lafayette Mendel and Thomas Burr Osborne showed that the nutritional value of soybean seeds could be increased by cooking, moisture or heat, that soy went from a farm animal feed to a human food. William Joseph Morse is considered the "father" of modern soybean agriculture in America. In 1910, he and Charles Piper began to popularize what was regarded as a relatively unknown Oriental peasant crop in America into a "golden bean", with the soybean becoming one of America's largest and most nutritious farm crops.
Sources: en.wikipedia.org
=== Eggs and hatchlings === C. brunneus lay eggs in a variety of habitats from chalk hills to sandy hills but most commonly lay their eggs in sandy, dry habitats. In the lab, C. brunneus prefer dry and compact substrates composed of fine particles such as sand. They produce the largest number of eggs between 28-35 °C degrees. In theory, smaller eggs should have higher mortality rates because of reduced provisions provided within the egg. However researchers found that egg viability is greater in the southern populations where eggs are smaller. This can be explained by higher overwintering temperatures. Egg size is influenced by a number of factors. As maternal age increases so does egg size. At the beginning of the breeding season females lay smaller eggs compared to the end of the breeding season. Eggs laid in the last part of the breeding season are smaller in size due to deteriorating maternal health. Research suggests that there is no correlation between stage of development and water uptake. While eggs can withstand a large amount of water loss they cannot survive complete desiccation. Therefore, it is not important at what point water is absorbed, it is only important that water is absorbed at some point. A larger egg size generally results in a larger hatchling and adult size. Eggs laid by C. brunneus from late August to early September are the heaviest, hatch the latest, and have heavier hatchlings. While earlier hatchlings are initially smaller, earlier hatchlings achieve a larger body size than later hatchlings.
== Obligations and enforcement == The conventions are legally binding, effectively under the Vienna Convention on the Law of Treaties (VCLT). The INCB, charged with monitoring treaty compliance, relies primarily on direct discussion with individual countries to address non-compliance issues. Formal drug treaty disagreements between countries over issues such as treaty compliance and amendment, import-export, jurisdiction, and extradition, are addressed in dispute provisions in each of the conventions that call for remedies including negotiation, mediation, arbitration, judicial proceedings, or other "peaceful means", or turning to the International Court of Justice. Periodically, the UN General Assembly holds special session meetings on drugs that provide a normative framework for the drug conventions. Falling out of compliance with the conventions, apart from denunciation by the UN and other countries, could have practical consequences, particularly for developing nations. The conventions regulate trade in legal pharmaceuticals, including the WHO list of essential drugs—leaving the system could make securing medicine more difficult. Being party to the three conventions is also a requirement for certain trade agreements, and for access to the European Union (EU). Enforcement measures rely largely on dialog and diplomacy. The INCB, in addition to discussion, can call out perceived non-compliance in its reports and in public statements – "naming and shaming" – and by alerting the CND and ECOSOC. Beyond that, it has no practical enforcement power.
Essentially, a spin-polarized magnetic surface acts as a chiral agent that initiates the adsorption and initial crystallization of one enantiomer of the relatively insoluble RAO. Furthermore, RAO displays conglomerate crystallization behavior, so homochiral RAO can be isolated from a racemic mixture provided that initial seeds are of a single enantiomer. The enantioselective crystallization of RAO on a magnetic surface results in an enantiomeric excess, although on early Earth magnetic surfaces (e.g., magnetite sediments) this initial ee would be small due to nonuniformities in the magnetization of the surface. This occurs because Earth's geomagnetic field only induces a weak magnetization on ferromagnetic minerals. However, due to the CISS effect, interaction between initial enantiopure RAO crystals would strengthen the net magnetization of the magnetic surface which would in turn allow for increased chiral selectivity in RAO adsorption, resulting in a positive feedback loop between surface electron spin-polarization and RAO chiral purity. Accordingly, multiple RAO dissolution and recrystallization cycles could amplify an initial CISS effect-induced enantiomeric excess to full homochirality. Experimental results indicate that full homochirality (ee=100%) can be achieved in only two crystallization steps.
== External links == Quantities, Units and Symbols in Physical Chemistry (IUPAC green book) An introductory video on Mass Spectrometry The Royal Society of Chemistry NIST Standard Reference Database 1A v17
Sources: en.wikipedia.org
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.
Tuftsin is a natural tetrapeptide derived from the Fc portion of immunoglobulin G. Selank retains that tetrapeptide at its N-terminus and adds three residues to improve resistance to enzymatic breakdown. The relationship is structural, and the two molecules are not interchangeable in experimental work.
It holds a product registration in Russia for intranasal use as an anxiolytic. Registrations of that kind are not automatically accepted by regulators elsewhere. In most other countries it is treated as an unapproved substance or a research material.
Dry powder is normally held at -20 degrees Celsius or below in a sealed, light-protected container with desiccant. Brief room-temperature handling during weighing is generally tolerated. Storage instructions vary between suppliers, so the accompanying certificate of analysis should be followed.