The short version of peptidase fits in a sentence. The long version — which is the one that helps — is below.
Reviewed 2026-08-01. Anything still debated is marked as such rather than presented as settled.
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.
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.
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.
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.
| Property | Value | Notes |
|---|---|---|
| Primary route studied | Intranasal | Also examined parenterally in animal work |
| Reported plasma half-life | Minutes to tens of minutes | Values vary widely between reports |
| Main model systems | Rodent behavioural and cell assays | Human trials are few and small |
| Principal proposed targets | GABA-A receptor, GABA transaminase | Monoamine and neurotrophic pathways also reported |
| Evidence grade | Preliminary | Limited independent replication |
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.
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.
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.
Pharmacokinetic data are limited. Like most short peptides, Selank is vulnerable to plasma and tissue peptidases, and its measured half-life in circulation is short, on a minutes scale. The Pro-Gly-Pro tail slows this degradation but does not eliminate it. Intranasal administration is the route described in most reports, with absorption through the nasal mucosa and a hypothesized path into the central nervous system that avoids the blood-brain barrier. Direct measurements of human brain exposure are unavailable, so distribution claims rest on inference from animal work.
Clinical evidence comes mainly from small studies conducted in Russia, several of which were open-label or lacked robust blinding. Reported outcomes include lower anxiety scores, changes in attention measures, and effects on asthenic states following illness. Sample sizes are typically in the tens of participants, and independent replication outside the region is scarce. Reviews published in English generally note the limited methodological quality of the underlying trials. Whether the compound produces clinically meaningful effects under rigorous conditions remains unresolved.
Proposed mechanisms center on modulation of the GABA system, but no single molecular target has been confirmed. Rodent studies report changes in GABA-A receptor expression and in the turnover of serotonin, dopamine, and norepinephrine in several brain regions. Increases in brain-derived neurotrophic factor and its receptor have also been described after repeated administration. These findings come largely from animal models, and the degree to which they describe human neurochemistry remains an open question. The mechanism is best characterized as multi-system and not fully resolved.
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.
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.
=== Allergy === A study published online in March 2008 showed that Colostrinin is non-allergenic and can prevent allergic inflammation due to common indoor and outdoor allergens. The study used a well characterized mouse model of allergic airway inflammation. Colostrinin (given orally, intranasally or intraperitoneally) significantly decreased IgE/IgG1 production, airway eosinophilia, mucin production and hypersensitivity induced by allergenic extracts from ragweed pollen and house dust mites. In contrast, colostrum induced positive inflammatory responses.
European Center for Disease Prevention and Control U.S. Centers for Disease Control and Prevention, Infectious Disease Society of America (IDSA) Vaccine Research Center Information concerning vaccine research clinical trials for Emerging and re-Emerging Infectious Diseases. Microbes & Infection (journal)
=== Libertarianism and capitalism === In a 2001 interview with Reason, Hitchens said he had been interested in libertarian ideas when he was younger, but set aside those interests in the 1960s. He stated that capitalism had become the more revolutionary economic system, and he welcomed globalisation as "innovative and internationalist", but added, "I don't think that the contradictions, as we used to say, of the system, are by any means all resolved." He also stated that he had a renewed interest in the freedom of the individual from the state, but that he still considered libertarianism "ahistorical" both on the world stage and in the work of creating a stable and functional society, adding that libertarians are "more worried about the over-mighty state than the unaccountable corporation" whereas "the present state of affairs ... combines the worst of bureaucracy with the worst of the insurance companies." He also said that libertarians did not have a clear foreign policy stance. In a 2001 C-SPAN appearance, he told a caller:
Sources: en.wikipedia.org
In Australian law, most employees have the right to reasonable notice before dismissal, and dismissals must be for a fair reason, however these rights are not universally upheld. At common law, everyone has the right to reasonable notice before either side terminates a contract. The longer that people work for an employer, the more notice becomes reasonable, reflecting the concept of mutual respect. For example, in Quinn v Jack Chia (Australia) Mr Quinn had been initially hired on a contract with a one-month notice, but had worked for years, taking on senior responsibilities, and making personal sacrifices for his employer. The court held he was entitled to 12 months, not one month as the contract had said, given his length of service, seniority and dedication over the years. A longer period of notice could also be expressly or impliedly agreed. For instance, in Walker v Citigroup Global Markets Australia Pty Ltd an investment banker was promised during negotiations that if he took a new position he would get a guarantee bonus after a year's work, and a higher job title, but before the job had begun the employer terminated and argued that Walker was due only one month's notice according to the standard termination clause. The Federal Court held that despite the termination clause, the promise of a bonus indicated the contract was meant to run for at least one year, so Walker was awarded damages for a year, plus damages for loss of opportunity to remain in employment longer.
== History == Opicapone was authorised for medical use in the European Union in June 2016. In February 2017, its developer Bial sold exclusive marketing rights for the United States and Canada to Neurocrine Biosciences for an initial payment of US$30 million. Opicapone was authorised for medical use in the United States in April 2020. Opicapone was approved based on evidence from two clinical trials (Trial 1/ NCT01568073, and Trial 2/NCT01227655) of 522 participants with Parkinson's disease (PD) whose symptoms were not well controlled while receiving their regular PD treatment. Trial 1 was conducted at 104 sites in 19 European countries, and Trial 2 was conducted at 69 sites in Argentina, Australia, Belgium, Chile, Czech Republic, Estonia, India, Israel, South Korea, Russia, South Africa and UK. There were two 12-week trials conducted in Parkinson's disease (PD) participants with inadequate control of their Parkinson's symptom ("off" time) while receiving carbidopa/levodopa PD medications. Participants were randomly selected to receive either opicapone or a placebo capsule once a day. Neither the participants nor the health care providers knew which treatment was being given until the trial was completed. In all of the trials, the participants kept daily diaries of the number of hours of "off" time for the three days before the evaluation visit. The benefit was evaluated by measuring the change from baseline in total daily "off" time in opicapone- and placebo-receiving participants.
== Hazards == Radium is highly radioactive, as is its immediate decay product, radon gas. When ingested, 80% of the ingested radium leaves the body through the feces, while the other 20% goes into the bloodstream, mostly accumulating in the bones. This is because the body treats radium as calcium and deposits it in the bones, where radioactivity degrades marrow and can mutate bone cells. Exposure to radium, internal or external, can cause cancer and other disorders, because radium and radon emit alpha and gamma rays upon their decay, which kill and mutate cells. Radium is generally considered the most toxic of the radioactive elements. Some of the biological effects of radium include the first case of "radium-dermatitis", reported in 1900, two years after the element's discovery. The French physicist Antoine Becquerel carried a small ampoule of radium in his waistcoat pocket for six hours and reported that his skin became ulcerated. Pierre Curie attached a tube filled with radium to his arm for ten hours, which resulted in the appearance of a skin lesion, suggesting the use of radium to attack cancerous tissue as it had attacked healthy tissue. Handling of radium has been blamed for Marie Curie's death, due to aplastic anemia, though analysis of her levels of radium exposure done after her death find them within accepted safe levels and attribute her illness and death to her use of radiography. A significant amount of radium's danger comes from its daughter radon, which as a gas can enter the body far more readily than can its parent radium.
The Brazilian press was officially born in Rio de Janeiro on 13 May 1808 with the creation of the Royal Printing National Press by the Prince Regent John. The Gazeta do Rio de Janeiro, the first newspaper published in the country, began to circulate on 10 September 1808. The largest newspapers nowadays are Folha de S.Paulo, O Globo, and O Estado de S. Paulo. Radio broadcasting began on 7 September 1922, with a speech by then President Epitácio Pessoa, and was formalized on 20 April 1923 with the creation of the "Radio Society of Rio de Janeiro". Television in Brazil began officially on 18 September 1950, with the founding of TV Tupi by Assis Chateaubriand. Since then, television has grown in the country, creating large commercial broadcast networks such as Globo, SBT, RecordTV, Bandeirantes and RedeTV. By the mid-1960s, Brazilian universities had installed mainframe computers from IBM and Burroughs Large Systems. In the 1970s and 1980s, the Brazilian government restricted foreign imports to protect the local manufacturing of computers. In the 1980s, Brazil produced half of the computers sold in the country. By 2009, the mobile phone and Internet use in Brazil was the fifth largest in the world. As of early 2025, internet penetration in Brazil stood at 86.2% of the total population (183 million individuals), and the ratio of cellular mobile connections to the total population was 102% (217 million active connections). In May 2010, the Brazilian government launched TV Brasil Internacional, an international television station, initially broadcasting to 49 countries.
Sources: en.wikipedia.org
Reports describe modulation of GABA signalling, changes in monoamine turnover and effects on neurotrophic factor expression. These observations come mainly from animal and cell studies. A single unifying mechanism has not been demonstrated.
The peptide enters plasma rapidly and is broken down by ordinary proteases into amino acids and shorter fragments. Reported half-lives are short. Whether meaningful amounts of the intact molecule reach the brain is an open question.
Most clinical reports are small, published in Russian and not independently replicated. English-language reviews highlight the absence of large randomised trials. Conclusions about efficacy should be treated as provisional.
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.