lyophilized powder is one of those subjects where the details matter more than the headlines. This page pulls together the background, the mechanisms, and the practical points readers ask about most.
Updated 2025-09-25. Numbers and descriptions here follow the published literature rather than marketing material.
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.
Once dissolved, the peptide is markedly less stable than the dry powder. Aqueous solutions are subject to backbone hydrolysis and to microbial growth when they are handled without sterile technique. Buffered solutions near neutral pH are common for short-term laboratory work, while acidic conditions are sometimes used to improve solubility. Analytical laboratories generally prepare working solutions fresh rather than storing them, and a residual water film left in a reopened vial can seed degradation even when the container appears dry.
Reversed-phase high-performance liquid chromatography is the standard technique for estimating peptide purity. The result is a peak-area percentage, which describes how much of the detected material elutes as the main peak in one run. Mass spectrometry confirms the molecular mass and can reveal truncated, adducted, or otherwise modified species. Amino acid analysis or tandem mass spectrometry can address sequence fidelity when identity is in doubt. None of these measurements, taken alone, establishes that a sample is fit for any specific purpose.
Lyophilized selank is normally supplied as a dry powder and is considered stable for extended periods when kept cold and dry. Moisture uptake is the main practical threat, because absorbed water promotes both hydrolysis and aggregation in the solid state. Vials are usually warmed to room temperature before opening so that condensation does not form on the powder. Supplier documentation commonly specifies -20 °C for routine storage, with -80 °C used for material intended to be archived for years.
| Property | Value | Notes |
|---|---|---|
| Identity confirmation | Reversed-phase HPLC retention time versus reference standard | Retention depends on column, gradient, and ion-pairing agent |
| Mass confirmation | Electrospray or MALDI mass spectrometry | Doubly protonated ion near m/z 377 is consistent with about 752 Da |
| Typical purity specification | 95 percent or higher by chromatographic peak area | Lower values suggest truncated or modified peptide species |
| Storage of lyophilized powder | -20 °C, desiccated, protected from light | Powder tolerates long storage better than solution |
| Storage of solution | 2-8 °C for short periods | Freeze-thaw cycling promotes aggregation and surface adsorption |
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.
Reported activity for Selank centers on anxiolytic and nootropic effects. Russian clinical reports describe use in anxiety and in cognitive or attention-related complaints. Most of this evidence comes from studies conducted by the same research groups that developed the peptide. Independent replication in other countries remains limited, and no major Western regulatory agency has approved the compound for any indication. The gap between local reports and external verification is a recurring point in discussions of the peptide.
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.
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.
Selank is a synthetic heptapeptide with the sequence Thr-Lys-Pro-Arg-Pro-Gly-Pro. It was designed at the Institute of Molecular Genetics of the Russian Academy of Sciences as a structural analogue of tuftsin, a naturally occurring tetrapeptide fragment of the immunoglobulin heavy chain. The added Pro-Gly-Pro tail was intended to slow enzymatic degradation and extend biological activity. In Russia it is registered as an anxiolytic nasal preparation, while regulators elsewhere have not approved it for clinical use.
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.
The compound was designed at the Institute of Molecular Genetics of the Russian Academy of Sciences during the 1980s and 1990s. The stated design goal was to retain the immunomodulatory and central nervous system activity attributed to tuftsin while improving resistance to enzymatic breakdown. Adding a proline-rich tail to the short parent peptide was a deliberate strategy, because proline residues restrict the conformations available to many peptidases. The same laboratory produced Semax, an ACTH fragment analog, and both compounds were developed in parallel as short, enzymatically stabilized peptides intended for intranasal use.
Selank is not a naturally occurring peptide and has no known endogenous counterpart in human physiology. Russian-language sources frequently call it TP-7, while English-language sources use the name Selank almost exclusively. Database indexing is uneven, partly because early reports appeared in regional journals that are not widely cataloged. Some summaries describe the material as a tuftsin analog and others as a synthetic heptapeptide; the labels overlap rather than conflict. Citing the primary sequence resolves ambiguity more reliably than the research or trade name alone.
Selank is a synthetic heptapeptide with the sequence Thr-Lys-Pro-Arg-Pro-Gly-Pro, written TKPRPGP in one-letter notation. Its structure consists of the immunomodulatory tetrapeptide tuftsin, Thr-Lys-Pro-Arg, extended at the carboxyl terminus by a Pro-Gly-Pro segment. The molecular formula is commonly given as C33H57N11O9, corresponding to a monoisotopic mass near 751.4 Da and an average molecular mass near 751.9 Da. All seven residues are proteinogenic amino acids, and the molecule carries no modified side chains or non-natural linkages.
Thomson (1937), Roman Catholic priest, professor at Providence College Thomas Merton (1938), Trappist monk, writer, humanist; author of The Seven Storey Mountain Robert Farrar Capon (1946), Episcopal priest and author Wesley Frensdorff (1948), former Episcopal bishop of Nevada Haskel Lookstein (1953), Modern Orthodox Rabbi; spiritual leader of Congregation Kehilath Jeshurun and principal of Ramaz School since 1966 Harold Kushner (1955), rabbi and writer Adi Da (1961), born Franklin Albert Jones, spiritual teacher; founder of a new religious movement, Adidam Michael Lerner (1964), liberal rabbi and editor of Tikkun magazine Elliot N. Dorff (1965), conservative rabbi, chairman of the Rabbinical Assembly's Committee on Jewish Law and Standards Joseph Goldstein (1965), vipassana expert Alan Senauke (1969), Soto Zen priest, folk musician, and poet residing at the Berkeley Zen Center; former director of the Buddhist Peace Fellowship Taigen Dan Leighton (1971), Soto Zen priest and teacher, academic at the Institute of Buddhist Studies C. John McCloskey (1975), Catholic priest who helped prominent figures convert to Catholicism, including Newt Gingrich, Bernard Nathanson, Sam Brownback, and Lawrence Kudlow Haviva Ner-David (1991), Israeli feminist activist and rabbi Sharon Brous (1995), first woman to be named most influential rabbi by Newsweek
In relation to the significance of the event(s) on career choice, when merging the categories ‘probably chosen career regardless’ with ‘possibly chosen career regardless’, and ‘unlikely chosen career regardless’ with ‘not considered career otherwise’, there is a slight majority in relation to the former. There are no significant differences in relation to demographic factors. In relation to whether one or more psychologically wounding experiences led to the choice of a career as a therapist, there is a significant difference within designation, gender, grouping gender and ethnicity, and, grouping gender and age. There are no significant differences within approach, ethnicity or age. The majority of the wounds were caused by events experienced directly by the respondents (65%) as opposed to indirectly or both. Within demographic factors, the causes of the wounding experiences leading to career choice are not statistically significant. The exact causes of the wounds vary enormously. The main categories are abuse, family life as a child, mental ill-health (own), social, family life as an adult, bereavement, mental ill-health (others), life-threatening, physical ill-health (others), physical ill-health (own), and, other. There are many implications for the future of the therapeutic world, focusing mainly on supervision and training. The largest prevalence study on lived experience within the mental health field by Victor et al.
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=== Beginnings === In September 1935, British chocolate manufacturer Rowntree's brought the first aerated chocolate, Aero, to market. At the time, Rowntree's had been struggling for several years to compete with rival chocolate maker Cadbury's Cadbury Dairy Milk and was looking for a new product to gain an advantage. The new chocolate was the outcome of significant research focused on developing a "count line" chocolate inspired by the recent introduction of the Mars bar to the UK market. Rowntree's patented their aerated chocolate broadly, covering variants such as chocolate with inclusions. As it was released to market, the new chocolate garnered strong sales and positive reviews, although some concerns were voiced within Rowntree's that the product would be a novelty. In their initial marketing, Rowntree's promoted aerated chocolate as better than solid chocolate: more digestible and lacking its "cloying after-taste". Cadbury objected to this and petitioned Rowntree's to stop denigrating rival chocolate makers in marketing.Rival chocolate markers attempted to position their existing product lines as competition (Cadbury their crumbly Flake bars, and Fry's their aerated-honeycomb-filled Crunchie bars), but none were seen by customers as "aerated" in the same sense as Aero. Further to their objections about aerated chocolate's digestibility, Cadbury contested the validity of the patent itself, arguing it overstepped and covered chocolates Cadbury already manufactured, as well as being malformed.
Sources: en.wikipedia.org
Mulligan (Larry Friedman), the leader; occasionally plays guitar Maggie (Sherry Wright), identified by her long blond pigtailed hair; keyboards Mike (Steven Einbender), an Italian; drums Manny (Benjamin Sands), a Black preteen; bass Micki (Mi-On Hahm), a young Asian girl; guitar (Mulligan, Maggie and Micki all sing lead vocals on most of the band's songs while Mike and Manny usually handle backing vocals.) The group's clubhouse is a basement in a brownstone apartment, fully furnished with a kitchen, shortwave radio, home gym, laboratory, and even a small stage where they rehearse their music. Their grownup advisor and mentor is Wilbur Dooright (Barry Michlin), a bespectacled, bumbling accountant who, in some episodes, gives the kids their assignments "from upstairs", assumed to be a secret government organization (paying homage to the spy films and TV shows of the day). Wilbur provides much of the comic relief throughout the series.
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=== Chemical precursor === Castor oil can react with other materials to produce other chemical compounds that have numerous applications. Transesterification followed by steam cracking gives undecylenic acid, a precursor to specialized polymer nylon 11, and heptanal, a component in fragrances. Breakdown of castor oil in strong base gives 2-octanol, both a fragrance component and a specialized solvent, and the dicarboxylic acid sebacic acid. Hydrogenation of castor oil saturates the alkenes, giving a waxy lubricant. Castor oil may be epoxidized by reacting the OH groups with epichlorohydrin to make the triglycidyl ether of castor oil which is useful in epoxy technology. This is available commercially as Heloxy 505. The production of lithium grease consumes a significant amount of castor oil. Hydrogenation of castor oil yields 12-hydroxystearic acid, a precursor to lithium 12-hydroxystearate, a thickener in lubricating greases. Since it has a relatively high dielectric constant (4.7), highly refined and dried castor oil is sometimes used as a dielectric fluid within high-performance, high-voltage capacitors.
=== Other === A relationship between intra-operative blood transfusion and cancer recurrence has been observed in colorectal cancer. In lung cancer intra-operative blood transfusion has been associated with earlier recurrence of cancer, worse survival rates and poorer outcomes after lung resection. Suppression of the immune system by blood transfusion has been implicated as playing a role in more than 10 different cancer types, through mechanisms involving the innate and adaptive immune system. Five major mechanisms for this include the lymphocyte-T set, myeloid-derived suppressor cells (MDSCs), tumor-associated macrophages (TAMs), natural killer cells (NKCs), and dendritic cells (DCs). Blood transfusion may modulate the activity of antitumor CD8+ cytotoxic T lymphocytes (CD8+/CTL), temporal response of Tregs, and the STAT3 signaling pathway. The role of the antitumor immune response in cancer therapeutics was explored historically through the use of bacteria to enhance the antitumor immune response and more recently in cellular Immunotherapy. However, the impact of transfusion-related immunomodulation (TRIM) on cancer progression has not been definitively established and requires further study. In retrospective studies, blood transfusion has been associated with worse outcomes after cytoreductive surgery and HIPEC. However, correlation does not prove causation, and transfused patients often have more complicated surgeries and more underlying cardiopulmonary disease compared to untransfused patients; conclusions should be based on prospective randomized controlled trials.
Most of these exacerbations were mild to moderately severe and developed more often in patients who were older in age or had generalized myasthenia gravis, myasthenia gravis with bulbar symptoms, severe symptoms, a thymoma, or a history of thymectomy to remove a thymoma. These studies, however, were mostly of low quality. Prospective studies comparing the effects of the different corticosteroids to define the rate and severity of the myasthenia exacerbations are needed. Calcium channel blockers: Calcium channel blockers (e.g., felodipine, nifedipine, and verapamil) are drugs that lower blood pressure in people with hypertension. Felodipine and nifedipine are reported to worsen myasthenia gravis and nifedipine and verapamil are reported to cause respiratory failure in people with severe generalized myasthenia gravis. Penicillamine: Penicillamine is a chelation therapy drug used to treat various diseases (e.g., Wilson's disease). About 1-2% of individuals treated long term with penicillamine develop myasthenia gravis and/or develop low concentrations of antibodies to AChR. Their myasthenia gravis is often mild and predominantly ocular myasthenia gravis, becomes evident usually 6–7 months (range one month to 8 years) after starting the drug, and goes into complete remission in 70% of the cases within 6–10 months after discontinuing the drug. Botulinum toxin A: Botulinum toxin A (sold under the brand name Botox, Jeuveau, and Xeomin) blocks transmission at neuromuscular junctions to paralyze the muscles into which it is injected.
Sources: en.wikipedia.org
Identity is confirmed by matching the retention time in reversed-phase chromatography against a reference standard and by measuring the molecular mass with mass spectrometry. Tandem mass spectrometry or amino acid analysis can verify the sequence of the seven residues. Because the peptide contains no aromatic amino acids, detection at 280 nm is not useful.
Lyophilized powder is normally stored desiccated at -20 °C, protected from light and moisture. Powder kept under these conditions is generally stable for long periods. Solutions are less stable and are usually prepared immediately before use.
A purity value from one chromatographic method does not capture every possible impurity. Related peptides with similar retention behavior, counterions, and residual solvents may not appear in the same analysis. Independent testing with an orthogonal method provides stronger assurance of identity and content.
Sealed, desiccated storage at -20 °C or colder is the standard recommendation for research-grade material. Vials should reach room temperature before they are opened, which limits condensation. Repeated temperature cycling is discouraged.