Everything below concerns pharmacokinetics. We keep the language plain, cite what the science says, and separate well-supported claims from open questions.
Last reviewed on 2025-12-19. Where a claim depends on a specific study, the study is described rather than over-claimed.
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.
Animal studies have examined behaviour in tests of anxiety, memory retention and stress response, and several report changes in neurotrophic or neurotransmitter-related markers. The human evidence base is much smaller, consisting mainly of short trials conducted in Russia with limited reporting in English-language journals. Sample sizes are modest and outcome measures vary between studies, so the findings are best described as preliminary. Independent replication under modern trial standards has not been widely reported.
Outside its country of origin the compound is generally handled as a research chemical rather than an approved medicine. No regulatory approval from the United States Food and Drug Administration or the European Medicines Agency has been granted for human use. Identity and purity are normally checked by reverse-phase high-performance liquid chromatography, with mass spectrometry used to confirm the molecular mass. Lyophilised material is stored cold and desiccated, and repeated freeze-thaw cycles are avoided.
| 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 |
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.
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.
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.
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.
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.
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.
Erika Cremer (20 May 1900, Munich – 21 September 1996, Innsbruck) was a German physical chemist and Professor Emeritus at the University of Innsbruck who is regarded as one of the most important pioneers in gas chromatography, as she second conceived the technique in 1944, after Richard Synge and Archer J.P. Martin in 1941.
Unlike physical disabilities, persons with mental illness are perceived by the public to be in control of their disabilities and responsible for causing them. Furthermore, research respondents are less likely to pity persons with mental illness, instead reacting to psychiatric disability with anger and believing that help is not deserved. The behavioral impact (or discrimination) that results from public stigma may take four forms: withholding help, avoidance, coercive treatment, and segregated institutions.
=== By Administration === Medicines can also be categorized based on how they are administered. The route of administration can affect the speed and effectiveness of treatment. Below is a summary of common routes:
== Mass spectrometry == Generally this topic is discussed when covering mass spectrometry and occurs generally by the same mechanisms. To neutralize the positive charge on the ionization site a single two-electron transfer must be made. Neutralization of the positive charge at the ionization site is performed at the expense of the atom adjacent to the ionization site, transferring the positive charge to this atom as a result of the bond cleavage.
Sources: en.wikipedia.org
==== Metabolism ==== In vitro studies found very minimal metabolism of enobosarm by human cytochrome P450 enzymes. The greatest degree of oxidative metabolite generation occurred with CYP3A4. Upon incubation with human UDP-glucuronosyltransferase (UGT) enzymes, enobosarm glucuronide was generated, with a majority of this inactive metabolite being produced by UGT1A1 and UGT2B7. Enobosarm glucuronide is the primary circulating metabolite of enobosarm. Coadministration of the strong CYP3A4 inhibitor itraconazole had minimal impact on the pharmacokinetics of enobosarm and enobosarm glucuronide, whereas the strong CYP3A4 inducer rifampin reduced enobosarm peak levels by 23%, elimination half-life by 23%, and area-under-the-curve levels by 43%. Coadministration of the pan-UGT inhibitor probenecid with enobosarm resulted in similar peak levels of enobosarm but the elimination half-life of enobosarm was extended by 78% and area-under-the-curve levels increased by 50%. These data are consistent with the preclinical findings that enobosarm is a substrate of CYP3A4 and UGT enzymes. The metabolism of enobosarm is similar to that of the closely structurally related drug bicalutamide.
Ernst on developing the first two-dimensional NMR experiments, and established the nuclear Overhauser effect as a convenient way of measuring distances within proteins. This research later led to the complete assignment of resonances for among others the bovine pancreatic trypsin inhibitor and glucagon. In October 2010, Wüthrich participated in the USA Science and Engineering Festival's Lunch with a Laureate program where middle and high school students will get to engage in an informal conversation with a Nobel Prize–winning scientist over a brown-bag lunch. Wüthrich is also a member on the USA Science and Engineering Festival's Advisory Board and a supporter of the Campaign for the Establishment of a United Nations Parliamentary Assembly, an organisation which campaigns for democratic reform in the United Nations. Wüthrich is a member of the Executive Advisory Board of the World.Minds Foundation, where he contributes to international dialogue on science, research, and innovation policy.
This is a list of chemists. It should include those who have been important to the development or practice of chemistry. Their research or application has made significant contributions in the area of basic or applied chemistry.
Sources: en.wikipedia.org
== Characters == Erasmas (nickname "Raz"): The protagonist of Anathem; a Decenarian fraa from the Concent of Saunt Edhar. The neglected son of a lower-class family, he was collected by the concent at the age of eight. Orolo: A Decenarian fraa from the Concent of Saunt Edhar. He is an eminent cosmographer and Erasmas's mentor at the concent. He is banished for using forbidden technology to observe the alien ship in violation of the Discipline's isolation requirements. He dies while recovering the alien body from Orithena, and is canonized as a Saunt for his sacrifice. Arsibalt: A Decenarian fraa from the Concent of Saunt Edhar and one of Erasmas's friends. The estranged son of a religious official, he seeks to reconcile religion with theorics. Lio: A Decenarian fraa from the Concent of Saunt Edhar and one of Erasmas's friends. He's known as an absent-minded eccentric and is interested in military history, Vale-lore (martial arts), and unusual gardening techniques. He leads the space mission to destroy the alien weapon. Jesry: A Decenarian fraa from the Concent of Saunt Edhar and one of Erasmas's friends. Unlike Erasmas, Jesry comes from a prosperous family, and is bored with the routine of mathic life preceding the arrival of the aliens. He becomes famous for going into space with the Warden of Heaven (a religious leader of the Sæcular Power) to investigate the alien ship. Ala: A Decenarian suur from the Concent of Saunt Edhar. She becomes a major organizer of the Convox, and later, the Arbran resistance.
=== Box office === Nutty Professor II: The Klumps grossed $42.5 million in its opening weekend, beating out What Lies Beneath and Thomas and the Magic Railroad to reach the number one spot. At the time, it had the third-highest opening weekend for a 2000 film, behind Mission: Impossible 2 and X-Men. This also made it the biggest opening weekend for an Imagine Entertainment film, beating Ransom. The film would hold this record four months until How the Grinch Stole Christmas replaced it that November. It set a career record for Eddie Murphy, breaking the three-day record formerly held by Dr. Dolittle. The film managed to secure the fourth-highest July opening weekend, after X-Men, Men in Black and Independence Day. For its second weekend, it fell into second place behind Hollow Man with $18 million. In the United Kingdom, Nutty Professor II: The Klumps made $2.3 million in its opening weekend, ranking number one ahead of Hollow Man and Billy Elliot. It dropped into fourth place behind Dinosaur, Road Trip and Billy Elliot during its second weekend with $1.3 million. The film went on to generate a total gross of over $123.3 million in the United States and an additional $43 million in other territories, for a worldwide total of $166.3 million worldwide.
SOCl2 + H2O → 2 HCl + SO2 By a similar process it also reacts with alcohols to form alkyl chlorides. If the alcohol is chiral the reaction generally proceeds via an SNi mechanism with retention of stereochemistry; however, depending on the exact conditions employed, stereo-inversion can also be achieved. Historically the use of SOCl2 with pyridine was called the Darzens halogenation, but this name is rarely used by modern chemists.
==== Australia ==== Cocaine is a Schedule 8 controlled drug in Australia under the Poisons Standard. It is the second most popular illicit recreational drug in Australia behind cannabis. In Western Australia under the Misuse of Drugs Act 1981, 4.0g of cocaine is the amount of prohibited drugs determining a court of trial, 2.0g is the amount of cocaine required for the presumption of intention to sell or supply, and 28.0g is the amount of cocaine required for purposes of drug trafficking.
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.
Most published work uses intranasal application, either as drops or as a nasal spray. Injection routes appear in a smaller set of animal experiments. Oral use is uncommon in the literature because peptide breakdown and poor absorption limit this route.