Everything below concerns freeze-thaw. We keep the language plain, cite what the science says, and separate well-supported claims from open questions.
Updated 2026-06-19. Numbers and descriptions here follow the published literature rather than marketing material.
Lyophilized Selank, the dry powder form, is generally stored frozen at minus 20 degrees Celsius or colder for long-term keeping. The solid is hygroscopic and should stay sealed, dry, and protected from light. Once dissolved, the peptide is less stable and is usually held refrigerated at 2 to 8 degrees Celsius for short periods. Repeated freezing and thawing is avoided because it can promote aggregation and loss of activity. Buffers and pH choice also affect how long a solution remains usable.
Solubility behavior is a practical concern for handling. Selank dissolves readily in water and in common aqueous buffers, which simplifies preparation of working solutions. The choice of solvent, ionic strength, and pH can influence aggregation over time, particularly at higher concentrations. Aqueous solutions are typically sterile-filtered before use. Because stability depends on several variables, storage and handling notes should be treated as general guidance rather than fixed rules, and specific values are best confirmed against a certificate of analysis for each batch.
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.
Selank is a synthetic heptapeptide with the sequence Thr-Lys-Pro-Arg-Pro-Gly-Pro. It was designed as a stabilized analogue of tuftsin, a naturally occurring tetrapeptide fragment derived from the immunoglobulin heavy chain. The additional Pro-Gly-Pro segment at the carboxyl terminus is intended to slow enzymatic cleavage. The compound is usually described in the literature as a synthetic peptide with anxiolytic and cognitive-related activity, a label that reflects a research context rather than an approved therapeutic category.
| Property | Value | Notes |
|---|---|---|
| Solubility | Freely soluble in water | Also in aqueous buffers |
| Typical purity (HPLC) | 95 percent or higher | Lot-dependent |
| Dry powder storage | Minus 20 degrees Celsius | Sealed, dry, protected from light |
| Solution storage | 2 to 8 degrees Celsius | Short-term use |
| Identity confirmation | Mass spectrometry | ESI or MALDI-TOF |
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.
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.
Tuftsin, the parent structure, is a naturally occurring immunomodulatory tetrapeptide released from the Fc region of immunoglobulin G by spleen enzymes. Selank extends this four-residue sequence with three additional amino acids. The stated rationale is that the added tail slows enzymatic breakdown and may influence receptor interactions. How the full heptapeptide behaves at the molecular level is not firmly established, and proposed mechanisms often involve indirect modulation of neurotransmitter or immune signaling rather than a single defined target.
Selank is a synthetic heptapeptide developed in Russia. Its sequence is Thr-Lys-Pro-Arg-Pro-Gly-Pro, a seven-residue chain built around the natural tetrapeptide tuftsin. Researchers at the Institute of Molecular Genetics of the Russian Academy of Sciences first described the compound in the mid-1990s. The design combined the tuftsin core with an added Pro-Gly-Pro tail, a modification intended to extend the molecule's stability in biological fluids. Published work on the peptide has appeared mainly in Russian-language journals.
Pharmacokinetic data are sparse and largely derived from animal work. After intranasal administration the peptide appears in plasma within minutes, and reported half-lives are short, on the order of minutes to tens of minutes. Degradation proceeds through ordinary proteolytic cleavage into constituent amino acids and smaller fragments. Direct evidence that intact Selank reaches brain tissue in meaningful amounts is limited, and the extent of blood-brain barrier penetration is debated. Some authors argue that fragments, not the parent peptide, carry much of the observed activity.
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.
resD: plays a role in site-specific recombination, resolving plasmid multimers back to monomers at the cer site. ParM is a prokaryotic actin homologue which provides the force to drive copies of the R1 plasmid to opposite ends of rod shaped bacteria before division. CopA-like RNA, an antisense RNA involved in replication control of the plasmid.
== Organization and leadership == The National Institutes of Health (NIH) is composed of 27 Institutes and Centers, most of which include research programs led by a Scientific Director and conducted by federal researchers and their trainees at one of several NIH campus locations. Collectively, these research programs encompass the Intramural Research Program (IRP). The IRP includes the United States National Library of Medicine, an international resource for researchers, and the NIH Clinical Center, the world's largest clinical research hospital. Intramural researchers are affiliated with individual Laboratories, Branches or Centers, which are typically organized around common thematic research goals and approaches, much like a department or center at an academic institution. Within these larger structures, Principal Investigators run Sections or Units devoted to their independent research goals. Core facilities, supported by staff scientists and clinicians, are among the shared resources available to IRP researchers. Scientific interests are not bound by the organizational structure. There exists a full spectrum of scientific interest groups (called SIGs) that brings researchers from different Institutes and Centers together around common areas of scientific interest where ideas can be shared and collaborations initiated. In addition, institutes come together to work cooperatively on major initiatives focused on unraveling the complexities of disease.
== Further reading == Hartonen, Kari; Laitinen, Totti; Riekkola, Marja-Liisa (2011). "Current instrumentation for aerosol mass spectrometry". TrAC Trends in Analytical Chemistry. 30 (9): 1486–1496. doi:10.1016/j.trac.2011.06.007. ISSN 0165-9936.
From the late 1920s fresh vegetables were successfully processed through freezing by the Postum Company (the forerunner of General Foods), which had acquired the technology when it bought the rights to Clarence Birdseye's successful fresh freezing methods.
Since their establishment in 1952, Special Forces soldiers have operated in Vietnam, Cambodia, Laos, North Vietnam, Guatemala, Nicaragua, El Salvador, Colombia, Panama, Haiti, Somalia, Bosnia, Kosovo, 1st Gulf War, Afghanistan, Iraq, the Philippines, Syria, Yemen, Niger and, in an FID role, East Africa.
Sources: en.wikipedia.org
== Awards == In 2004 the ELGA CENTRA received an Industrial Product Design Award; in 2009 the PURELAB Ultra was the Readers Choice Laboratory Equipment winner: the ELGA PURELAB flex received the Instrument Business Outlook (IBO) Silver design award for Laboratory Equipment Industrial Design in 2009, the Aquatech China Innovation Gold Award in 2010 and the Industrial Product Design Gold Award, the Materials Innovation Gold Award, the dBA Design Effectiveness and the Red Dot Award in 2011; in 2011 the ELGA PURELAB Pulse also received the Scientists Choice Award.
Phenadoxone (trade names Heptalgin, Morphidone, and Heptazone) is an opioid analgesic of the open chain class (methadone and relatives) invented in Germany by Hoechst in 1947. It is one of a handful of useful synthetic analgesics which were used in the United States for various lengths of time in the 20 or so years after the end of the Second World War but which were withdrawn from the market for various or no known reason and which now are mostly in Schedule I of the United States' Controlled Substances Act of 1970, or (like phenazocine and bezitramide) in Schedule II but not produced or marketed in the US. Others on this list are ketobemidone (Ketogin), dextromoramide (Dimorlin, Palfium and others), phenazocine (Narphen and Prinadol), dipipanone (Diconal, Pipadone and Wellconal), piminodine (Alvodine), propiram (Algeril), anileridine (Leritine) and alphaprodine (Nisentil). Phenadoxone has a US DEA ACSCN of 9637 and has had a zero annual manufacturing quota under the Controlled Substances Act 1970. Its withdrawal from US distribution prior to the promulgation of said act is a large part of its Schedule I designation; it is, however, used as a legitimate medication in other countries and consumption is increasing worldwide as indicated below. Phenadoxone is generally considered to be a strong opioid analgesic and is regulated in much the same way as morphine where it is used. The usual starting dose is 10–20 mg and it has a duration of analgesic effect of 1 to 4 hours. Phenadoxone is not used at this time for purposes other than pain relief.
Equilin is a naturally occurring estrogen sex hormone found in horses as well as a medication. It is one of the estrogens present in the estrogen combination drug preparations known as conjugated estrogens (CEEs; e.g. Premarin) and esterified estrogens (EEs; e.g. Estratab, Menest). CEEs is the most commonly used form of estrogen medications in hormone replacement therapy (HRT) for menopausal symptoms in the United States. Estrone sulfate is the major estrogen in CEEs (about 50%) while equilin sulfate is the second major estrogen in the formulation, present as about 25% of the total.
==== Oxyhemoglobin ==== Oxyhemoglobin is formed during physiological respiration when oxygen binds to the heme component of the protein hemoglobin in red blood cells. This process occurs in the pulmonary capillaries adjacent to the alveoli of the lungs. The oxygen then travels through the blood stream to be dropped off at cells where it is utilized as a terminal electron acceptor in the production of ATP by the process of oxidative phosphorylation. It does not, however, help to counteract a decrease in blood pH. Ventilation, or breathing, may reverse this condition by removal of carbon dioxide, thus causing a shift up in pH. Hemoglobin exists in two forms, a taut (tense) form (T) and a relaxed form (R). Various factors such as low pH, high CO2 and high 2,3 BPG at the level of the tissues favor the taut form, which has low oxygen affinity and releases oxygen in the tissues. Conversely, a high pH, low CO2, or low 2,3 BPG favors the relaxed form, which can better bind oxygen. The partial pressure of the system also affects O2 affinity where, at high partial pressures of oxygen (such as those present in the alveoli), the relaxed (high affinity, R) state is favoured. Inversely, at low partial pressures (such as those present in respiring tissues), the (low affinity, T) tense state is favoured. Additionally, the binding of oxygen to the iron(II) heme pulls the iron into the plane of the porphyrin ring, causing a slight conformational shift. The shift encourages oxygen to bind to the three remaining heme units within hemoglobin (thus, oxygen binding is cooperative).
Sources: en.wikipedia.org
Reverse-phase HPLC is the usual method and gives a percentage purity value. Mass spectrometry then confirms the molecular mass. Together they provide a basic identity and purity profile for a lot.
Freeze-dried material is kept frozen, often at minus 20 degrees Celsius, and protected from light and moisture. Dissolved peptide is refrigerated for short-term use. Repeated freeze-thaw cycles are avoided.
A certificate of analysis typically lists purity by HPLC, the confirmed mass, appearance, and sometimes water or counter-ion content. It documents results for a specific batch. Details vary by supplier.
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.