This is a working overview of Intranasal delivery, written for readers who want more than a one-paragraph summary but less than a textbook.
This page was last updated on 2025-11-09 and is reviewed periodically as new material appears.
Published work on this peptide almost always uses intranasal delivery, with drops or a spray applied to the nasal mucosa. Some animal experiments have used subcutaneous or intraperitoneal injection, and a smaller number have compared routes directly. Oral administration is not a focus of the literature, because short peptides of this size are broken down by digestive enzymes and cross intestinal barriers poorly. How much of an intranasal dose reaches the bloodstream intact in humans remains an open question.
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.
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.
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.
| Property | Value | Notes |
|---|---|---|
| Common route | Intranasal | Also injected in some animal work |
| Solubility class | Freely soluble in water | Solid form is hygroscopic |
| Typical storage | About -20 degrees Celsius | Keep desiccated and dark |
| Purity method | Reverse-phase HPLC | Reported as area percent |
| Confirmatory method | Mass spectrometry | Verifies expected molecular mass |
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.
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.
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.
=== Relationship with other guerrillas === The Hukhbalahap's methods were generally terrorist in nature; for example, Ray Hunt, an American who led his own band of 3,000 guerrillas, said of the Hukbalahap that
Not all ants have the same kind of societies. The Australian bulldog ants are among the biggest and most basal of ants. Like virtually all ants, they are eusocial, but their social behaviour is poorly developed compared to other species. Each individual hunts alone, using her large eyes instead of chemical senses to find prey. Some species attack and take over neighbouring ant colonies. Extreme specialists among these slave-raiding ants, such as the Amazon ants, are incapable of feeding themselves and need captured workers to survive. Captured workers of enslaved Temnothorax species have evolved a counter-strategy, destroying just the female pupae of the slave-making Temnothorax americanus, but sparing the males (who do not take part in slave-raiding as adults).
=== Small molecule CGRP antagonists (gepants) === Ubrogepant is approved for acute treatment of migraines Rimegepant (BMS-927711) is approved for acute migraine treatment (since February 2020) and for preventive treatment of episodic migraines (since May 2021). Atogepant (AGN-241689) is approved for preventative treatment of migraines Zavegepant (BHV- 3500) is a nasal spray approved for acute treatment of migraines. Telcagepant (MK-0974), reached phase III clinical trials; development discontinued in 2011. Olcegepant (BIBN-4096BS) is a drug candidate BI 44370 TA (BI 44370) MK-3207 SB-268262
Portugal has a tradition of a humanistic criminal justice. The Portuguese Constitution defines the country as being one that is based on human dignity. It abolished capital punishment and life imprisonment in the 19th century, and forbids extradition in the case of either sentence possibly being imposed. The Portuguese Penal Code provides for a wide range of non-custodial sentences, with the aim of keeping a prison sentence a punishment of last resort. Portuguese penitentiary laws have traditionally been progressive, and based on rehabilitation as the main goal of the implementation of such a sentence. Since the 1980s, Portugal has strengthened LGBTQ rights and become one of Europe's most equal countries, although historical isolation and authoritarianism continues to shape social acceptance of LGBTQ people. In 2001, Portugal decriminalised the personal possession and consumption of all drugs. Portugal faces issues such as unwarranted use of force by law enforcement, racism and discrimination against minorities, migrant slavery, restrictions on freedom of association and collective bargaining, violations of wage, hour, and overtime laws, and persistent structural and institutional deficiencies in the prison system.
Sources: en.wikipedia.org
=== Psychological === It has been proposed that the initial encoding of events by such people includes semantic processing, and therefore semantic cues are used in retrieval. Once cued, the memory is retrieved as episodic and follows a pattern similar to that of a spreading activation model. This is particularly evident in Jill Price's case. She describes how one memory triggers another, which in turn triggers another and how she is powerless to stop it: "It's like a split screen; I'll be talking to someone and seeing something else." This theory serves to explain why hyperthymestics have both a sense of 'knowing' (semantic memory) and 'remembering' (episodic memory) during recollection. One writer claimed hyperthymesia may be a result of reviewing memories constantly to an obsessive-compulsive degree. However, Price has completely dismissed this article as "a load of crap", and hyperthymesiacs claim to never revisit uneventful memories. Other findings have shown that the tendencies to absorb new information and fantasise are personality traits that are higher in hyperthymestics than the rest of the population. These traits, absorption and fantasising, also correlated with a test which measures superior autobiographical memory within the hyperthymestic sample. McGaugh rejects the idea that hyperthymestic syndrome can be explained away so easily; he argues that nothing explains how subjects are able to memorise so much: "You'd have to assume that every day they rehearse it... The probability of these explanations dwindles as you look at the evidence."
1993/1579) Merchant Shipping (Prevention of Oil Pollution) (Amendment) Order 1993 (S.I. 1993/1580) Merchant Shipping (Prevention of Pollution by Garbage) (Amendment) Order 1993 (S.I. 1993/1581) International Carriage of Perishable Foodstuffs (Amendment) Regulations 1993 (S.I. 1993/1589) Swavesey Internal Drainage Board Award Drains Variation Order 1993 (S.I. 1993/1590) Wireless Telegraphy (Short Range Devices) (Exemption) Regulations 1993 (S.I. 1993/1591) Montrose Harbour Revision Order 1993 (S.I. 1993/1592) Local Government Superannuation (Scotland) Amendment Regulations 1993 (S.I. 1993/1593) Severn Bridge Regulations 1993 (S.I. 1993/1595)
== Side effects == Although melarsoprol cures about 96% of people with late stage disease, its toxicity limits its use. About 1–5% of people die during treatment. As a toxic organic compound of arsenic, melarsoprol is a dangerous treatment that is typically only administered by injection under the supervision of a licensed physician. Notable side effects are similar to arsenic poisoning. Among clinicians, it is colloquially referred to as "arsenic in antifreeze". Severe and life-threatening adverse reactions are associated with melarsoprol. It is known to cause a range of side effects including convulsions, fever, loss of consciousness, rashes, bloody stools, nausea and vomiting. In approximately 5–10% of cases, it causes encephalopathy. Of those, about 50% die due to encephalopathy-related adverse reactions. Additional potentially serious side effects of melarsoprol include damage to the heart, presence of albumin in the urine that could be associated with kidney damage, and an increase in blood pressure.
Sources: en.wikipedia.org
At least one person has been killed by carbon dioxide gas subliming off dry ice in coolers placed in a car. In 2020, three people were killed at a party in Moscow after 25 kg of dry ice was dumped in a pool; carbon dioxide is heavier than air, and so can linger near the ground, just above water level.
=== 1960s === During the 1960s, the main conflict in Colombia was between leftist guerillas and the central government. Key concerns included access to land, the battle between communist and far-right ideologies, and the marginalization of peasant populations. In the early 1960s, Colombian Army units loyal to the National Front began to attack peasant communities. This happened throughout Colombia, with the Colombian army deeming these peasant communities as enclaves for bandits and communists. It was the 1964 attack on the community of Marquetalia that motivated the later creation of FARC. Despite the infantry and police encirclement of the villages inside Marquetalia (3,500 men swept through the area), Manuel Marulanda managed to escape the army cordon. Unlike the rural FARC, which had roots in previous Liberal peasant struggles, the National Liberation Army (ELN) was mostly an outgrowth of university unrest. It would subsequently tend to follow a small group of charismatic leaders, including Camilo Torres Restrepo. Both guerrilla groups remained mostly operational in remote areas of the country during the rest of the 1960s. The Colombian government organized several short-lived counter-guerrilla campaigns in the late 1950s and early 1960s. The U.S. government and the CIA aided these efforts, which employed hunter-killer teams and involved U.S. personnel from the previous Philippine campaign against the Huks, who would later participate in the subsequent Phoenix Program in the Vietnam War.
=== Circulating plasma levels === Plasma from patients with advanced heart failure presents increased levels of HGF, which correlates with a negative prognosis and a high risk of mortality. Circulating HGF has been also identified as a prognostic marker of severity in patients with hypertension. Circulating HGF has been also suggested as a precocious biomarker for the acute phase of bowel inflammation.
Charles Brenner (born October 30, 1961) holds the position of Professor of Metabolic Regulation at University of Helsinki, having been recruited with support of the Research Council of Finland. Prior to this, he held the inaugural Alfred E Mann Family Foundation Chair of the Department of Diabetes & Cancer Metabolism at the Beckman Research Institute of the City of Hope National Medical Center and served as the Roy J. Carver Chair and head of biochemistry at the University of Iowa. Brenner is a major contributor in the field of nicotinamide adenine dinucleotide (NAD) metabolism and has developed targeted, quantitative methods for NAD metabolomics. Brenner discovered eukaryotic nicotinamide riboside (NR) kinase and nucleosidase pathways to NAD.
Sources: en.wikipedia.org
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.
Reported human trials are few, brief and originate mainly from one country. They describe effects on anxiety-related measures, but sample sizes are small and reporting is limited. The results are widely regarded as preliminary rather than confirmed.
Reverse-phase liquid chromatography is used to assess purity and separation of related impurities. Mass spectrometry confirms that the observed molecular mass matches the expected peptide. A certificate of analysis from the supplier is the usual document of record.
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.