The short version of certificate of analysis fits in a sentence. The long version — which is the one that helps — is below.
This page was last updated on 2025-11-20 and is reviewed periodically as new material appears.
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.
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.
| Property | Value | Notes |
|---|---|---|
| Appearance | White to off-white powder | Lyophilised solid form |
| Solubility class | Freely soluble in water | Hydrophilic heptapeptide |
| Dry storage temperature | -20 degrees Celsius or lower | Sealed, desiccated, protected from light |
| Solution storage | 2 to 8 degrees Celsius short term | Avoid repeated freeze-thaw cycles |
| Common identification method | Reversed-phase HPLC with mass spectrometry | Confirms purity and molecular mass |
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.
Measuring peptide exposure inside the brain is technically difficult. Selank is degraded rapidly in plasma, and assays must separate intact peptide from fragments, which favors targeted mass spectrometry over immunoassays alone. Reported half-lives are short, on the order of minutes, so effects observed hours later are attributed to downstream signaling rather than to the parent compound. Blood-brain barrier permeability is debated and rarely quantified directly. Gaps include absent dose-response characterization, inconsistent reporting of purity, and almost no pharmacokinetic data from human participants.
Selank is studied chiefly as an animal-model anxiolytic with proposed secondary effects on memory and immune signaling. Reported mechanisms include modulation of the GABA-A receptor complex, inhibition of enkephalin-degrading enzymes, and shifts in monoamine turnover within limbic structures. Some experiments describe increased expression of brain-derived neurotrophic factor in the hippocampus after repeated dosing. No single molecular target has been confirmed, and the peptide does not bind any receptor with the selectivity typical of a conventional small-molecule drug. Mechanism therefore remains a set of hypotheses rather than an established pathway.
Laboratory work relies on standard behavioral paradigms. Rodents are tested in the elevated plus maze, open field, and passive avoidance tasks, with outcomes compared against diazepam or vehicle controls. Intranasal dosing is used most often because it bypasses first-pass metabolism, though intraperitoneal and intravenous routes also appear in published protocols. Biochemical endpoints include tissue BDNF concentrations, cytokine levels, and monoamine metabolites. Human data are limited to small Russian trials reporting reduced anxiety scores; most were not prospectively registered, and few employed independent outcome assessment.
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.
=== Weissenbacher-Zweymüller syndrome === At least one identified mutation in the COL11A2 gene is responsible for Weissenbacher-Zweymüller syndrome. This mutation causes the amino acid glycine to be replaced with the amino acid glutamic acid at position 955 in the alpha 2 chain of type XI collagen (written as Gly955Glu). This mutation prevents collagen molecules from being assembled properly, which disrupts the structure of type XI collagen. These changes result in the characteristic signs and symptoms of Weissenbacher-Zweymüller syndrome.
== Chemistry == Indium has 49 electrons, with an electronic configuration of [Kr]4d105s25p1. In compounds, indium most commonly donates the three outermost electrons to become indium(III), In3+. In some cases, the pair of 5s-electrons are not donated, resulting in indium(I), In+. The stabilization of the monovalent state is attributed to the inert pair effect, in which relativistic effects lowers the energy of the 5s-orbital, observed in heavier elements. Thallium (indium's heavier homolog) shows an even stronger effect, manifested by the pervasiveness of thallium(I) vs thallium(III), Gallium (indium's lighter homolog) is only rarely observed in the +1 oxidation state. Thus, although thallium(III) is a moderately strong oxidizing agent, indium(III) is not, and many indium(I) compounds are powerful reducing agents. While the energy required to include the s-electrons in chemical bonding is lowest for indium among the group 13 metals, bond energies decrease down the group so that by indium, the energy released in forming two additional bonds and attaining the +3 state is not always enough to outweigh the energy needed to involve the 5s-electrons. Indium(I) oxide and hydroxide are more basic and indium(III) oxide and hydroxide are more acidic. A number of standard electrode potentials, depending on the reaction under study, are reported for indium, reflecting the decreased stability of the +3 oxidation state:
=== Western medicine === There has been a recent increase in research to confirm the efficacy of some of the claimed benefits of E. sinensis, as well as find additional possible uses within the medical field. Testing on immuno-suppressed mice has showed positive effects on immune system function. This points to an area of future research for human use. Chitosan extraction for utilization in production of nanofiber membranes used for wound dressings. Research around nanofiber dressings has increased in recent years. Shrimp and crab chitosan is usually utilized, E. sinensis chitosan extraction has aims to address seasonal and regional restrictions.
Sources: en.wikipedia.org
The United States and the Soviet Union engaged in competition vis-à-vis the arts. Cultural competition played out in Moscow, New York, London, and Paris. In 1946 America opened an exhibition called 'Advancing American Art' which gained popularity with the aims of expressing American art, in response the Soviets opened a respective exhibition showcasing Soviet Realism. The Soviets excelled at ballet and chess, the Americans at jazz and abstract expressionist paintings. The US funded its own ballet troupes, and both used ballet as political propaganda, using dance to reflect life style in the "battle for the hearts and minds of men." The defection of a premier dancer became a major coup. Chess was inexpensive enough—and the Russians always won until America unleashed Bobby Fischer. Vastly more expensive was the Space Race, as a proxy for scientific supremacy (with a technology with obvious military uses). As well when it came to sports the two countries both competed in the Olympics during the Cold War period which also created severe tension when the West boycotted the first Russian Olympics in 1980.
As the solidification rate slows down, however, the area fraction of the particle-rich phase drops indicating an increase in packing efficiency. At the same time, the competitive growth process is taking place, replacing r-crystals with z-crystals. At a certain point nearing the end of the transition zone, the particle-rich phase fraction rises sharply since z-crystals are less efficient at packing particles than r-crystals. The apex of this curve marks the point where only z-crystals are present (SSZ). During steady-state growth, after the maximum particle-rich phase fraction is reached, the efficiency of packing increases as steady-state is achieved. In 2011, researchers at Yale University set out to probe the actual spatial packing of particles within the walls. Using small-angle X-ray scattering (SAXS) they characterized the particle size, shape and interparticle spacing of nominally 32 nm silica suspensions that had been freeze-cast at different speeds. Computer simulations indicated that for this system, the particles within the walls should not be touching but rather separated from one another by thin films of ice. Testing, however, revealed that the particles were, in fact, touching and more than that, they attained a packed morphology that cannot be explained by typical equilibrium densification processes.
== Births == 17 January - William Saunders, poet (died 1851) 1 February - Jane Williams (Ysgafell), writer (died 1885) 9 April - Theophilus Redwood, pharmacist (died 1892) 21 April - Sir George Cornewall Lewis, statesman (died 1863) date unknown Joseph Murray Ince, painter (died 1859) Harry Longueville Jones, archæologist, artist and Inspector of Schools for Wales (died 1870) David Pugh, politician (died 1890) probable - Thomas Rees (Twm Carnabwth), Rebecca rioter (died 1876)
==== Post-traumatic growth in constructive journalism ==== The phenomenon of PTG is applicable to many disciplines. The construct is important not only for just soldiers, emergency responders, and survivors of traumatic events, but on average, for everyday citizens facing typical adversity. One way to expose citizens to stories of PTG is through constructive journalism. Constructive journalism, as defined by PhD student Karen McIntyre at University of North Carolina Chapel Hill, is "an emerging style of journalism in which positive psychology techniques are applied to news work with the aim of engaging readers by creating more productive news stories, all while maintaining core journalistic functions". Cathrine Gyldensted, an experienced reporter with a Masters in applied positive psychology and coauthor of two books, demonstrated that typical news reporting, which is associated with negative valence, harms mood. Using PTG to focus on victims' strengths and instances of overcoming adversity encourages readers to implement similar ideals in their own lives. "So the goal of positive psychology in well-being theory is to measure and to build human flourishing." Combining positive psychology constructs like PTG, PERMA, and "broaden and build" with journalism could potentially improve affect and inspire individuals about the benefits of positive psychology. PERMA not only plays a role in our own personal lives but also can be used for public major news stories.
Sources: en.wikipedia.org
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.
Reversed-phase HPLC establishes purity, while mass spectrometry confirms the expected molecular mass. Sequence confirmation may use tandem mass spectrometry or peptide mapping. A certificate of analysis typically reports these results alongside the analytical method applied.
In Russia it is a registered medicine available by prescription. In many other countries it is not approved for human use and is supplied only as a research chemical. Import and possession rules differ by jurisdiction, and buyers are responsible for checking local requirements.
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.