Intranasal delivery raises a handful of sensible questions. This page answers them in order, starting with the fundamentals and moving to applications.
This page was last updated on 2025-08-13 and is reviewed periodically as new material appears.
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.
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.
| Property | Value | Notes |
|---|---|---|
| Typical purity report | 95% or higher by HPLC | Area percentage at 214 nm |
| Identity confirmation | Mass spectrometry | Electrospray or MALDI |
| Powder storage | -20 C, desiccated | Protect from light |
| Solution storage | 2-8 C short term | Freeze aliquots for longer |
| Quality document | Certificate of analysis | States method and value |
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.
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.
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.
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.
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.
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.
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.
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.
==== Chemical reactions in seawater ==== Silver nanoparticles are thermodynamically unstable in oxic environments. In seawater, silver oxide is not thermodynamically favored when chloride and sulfur are present. On the surface where O2 is present in much greater quantities than chloride or sulfur, silver reacts to form a silver oxide surface layer. This oxidation has been shown to occur in nanoparticles as well, despite their shell.Dissolution of Ag2O in Water:Ag2O + H2O → 2Ag− + 2OH− The nano-size of the particles aids in oxidation since their smaller surface area increases their redox potential. The silver oxide layer easily dissolves in water because of its low Ksp value of 4 × 10−11. Possible Oxidation Reactions of Silver:Ag + O2 → Ag+ + O2−4Ag + O2 → 4Ag+ + 2O2−In aerobic, acidic seawater, oxidation of Ag can occur through the following reaction:Oxidation of Silver in Seawater:2Ag(s) + ½ O2(aq) + 2H+(aq) ⇌ 2Ag+(aq) + H2O(l) The formation of these Ag+ ions are a concern for environmental health, as these ions freely interact with other organic compounds, such as humic acids, and disrupt the normal balance of an ecosystem. These Ag+ ions will also react with Cl− to form complexes such as AgCl2−, AgCl32−, and AgCl43−, which are bioavailable forms of silver that are potentially more toxic to bacteria and fish than silver nanoparticles.
Multiple limited series or one-shot comic books that tie into the MCU films and television series have been published by Marvel Comics. They are intended to tell additional stories about existing characters or to make connections between MCU projects, without necessarily expanding the universe or introducing new concepts or characters.
== Pharmacology == Chlordiazepoxide acts on benzodiazepine allosteric sites that are part of the GABAA receptor/ion-channel complex and this results in an increased binding of the inhibitory neurotransmitter GABA to the GABAA receptor thereby producing inhibitory effects on the central nervous system and body similar to the effects of other benzodiazepines. Chlordiazepoxide is an anticonvulsant. Chlordiazepoxide is preferentially stored in some organs including the hearts of neonates. Absorption by any administered route and the risk of accumulation is significantly higher in neonates. The withdrawal of chlordiazepoxide during pregnancy and breast feeding is recommended, as chlordiazepoxide rapidly crosses the placenta and also is excreted in breast milk. Chlordiazepoxide also decreases prolactin release in rats. Benzodiazepines act via micromolar benzodiazepine binding sites as Ca2+ channel blockers and significantly inhibit depolarization-sensitive Calcium uptake in animal nerve terminal preparations. Chlordiazepoxide inhibits acetylcholine release in mouse hippocampal synaptosomes in vivo. This has been found by measuring sodium-dependent high affinity choline uptake in vitro after pretreatment of the mice in vivo with chlordiazepoxide. This may play a role in chlordiazepoxide's anticonvulsant properties.
=== Cancer === In response to a report of precancerous changes in the pancreases of rats and organ donors treated with the DPP-4 inhibitor sitagliptin, the US FDA and the European Medicines Agency each undertook independent reviews of all clinical and preclinical data related to the possible association of DPP-4 inhibitors with pancreatic cancer. In a joint letter to the New England Journal of Medicine, the agencies stated that they had not yet reached a final conclusion regarding a possible causative relationship. A 2014 meta-analysis found no evidence for increased pancreatic cancer risk in people treated with DPP-4 inhibitors, but owing to the modest amount of data available, the authors were unable to completely exclude possibly increased risk.
== Temperature stability == After an hour at 50 °C (122 °F), 83% of the enzyme remains, while at 40 °C (104 °F), practically 100% remains. The proteolytic activity of concentrated bromelain solutions remains relatively stable for at least 1 week at room temperature, and multiple freeze-thaw cycles or exposure to the digestive enzyme trypsin have little effect on it.
Sources: en.wikipedia.org
So a consequence of this social hierarchy is that the Locator discloses various degrees of information, based on the staff member and their rights. The Locator does not want to disclose information that could jeopardize his relationship with the members of staff. The Locator adheres to the rights of each class. Social hierarchy is also related to attitudes towards technologies. This was inferred based on the attitude of various jobs towards their lab badge. Their attitude depended on how that job viewed their badge from a standpoint of utility, (how is the badge useful for my job) morality (what are my morals on privacy, as it relates to being tracked by this badge) and relations (how will I be seen by others if I refuse to wear this badge). For example, a receptionist would view the badge as useful, as it would help them locate members of staff during the day. Illustrating relations, researchers would also wear their badge due to informal pressures, such as not wanting to look like a spoil-sport, or not wanting to draw attention to themselves. Another finding is the resistance to change in a social organization. Staff members feel ill at ease when changing patterns of entitlement, obligation, respect, informal and formal hierarchy, and more. In summary, differences in attitude among members of the laboratory are explained by social organization: A person's attitudes are intimately related to the role they have in an organization. This hierarchy helps understand information distribution, control, and attitudes towards technologies in the laboratory.
This RNA was synthesized using activated ribonucleotides. Additionally, these RNA oligomers could only be synthesized under certain conditions. Pores at deep sea hydrothermal vents are suggested to have been occupied by membrane-bound compartments which promoted biochemical reactions. Metabolic intermediates in the Krebs cycle, gluconeogenesis, amino acid bio-synthetic pathways, glycolysis, the pentose phosphate pathway, and including sugars like ribose, and lipid precursors can occur non-enzymatically at conditions relevant to deep-sea alkaline hydrothermal vents. If the deep marine hydrothermal setting was the site, then life could have arisen as early as 4.0–4.2 Gya. If life evolved in the ocean at depths of more than ten meters, it would have been shielded both from impacts and the then high levels of solar ultraviolet radiation. The available energy in hydrothermal vents is maximized at 100–150 °C, the temperatures at which hyperthermophilic bacteria and thermoacidophilic archaea live.
=== Discontinuation syndrome === SSRI discontinuation syndrome has been reported when treatment is stopped. It includes sensory, and gastrointestinal symptoms, dizziness, lethargy, and sleep disturbances, as well as psychological symptoms such as anxiety/agitation, irritability, and poor concentration. Electric shock-like sensations are typical for SSRI discontinuation. Withdrawal symptoms can occur when this medicine is suddenly stopped, such as paraesthesiae, sleeping problems (difficulty sleeping and intense dreams), feeling dizzy, agitated or anxious, nausea, vomiting, tremors, confusion, sweating, headache, diarrhea, palpitations, changes in emotions, irritability, and eye or eyesight problems. Citalopram doses should be reduced gradually when treatment is finished.
=== Ownership and promotion === Knoll pharmaceuticals, originally founded in Germany in 1886, became a subsidiary of BASF (a German chemical company) in 1975. It was under their control when Vicoprofen was originally developed and approved. In March 2000, Knoll Pharmaceuticals and Abbott Laboratories, an American health care company, announced a co-promotion agreement for Vicoprofen, in which Abbott would promote Vicoprofen to its network of buyers, including physicians, hospitals, and surgical centers. In June 2002, Abbott Laboratories, paid $6.9 billion to acquire the entire Knoll pharmaceutical unit from BASF, including Vicoprofen.
=== Weight loss industry === There is a substantial market for products which claim to make weight loss easier, quicker, cheaper, more reliable, or less painful. These include books, DVDs, CDs, cremes, lotions, pills, rings and earrings, body wraps, body belts and other materials, fitness centers, clinics, personal coaches, weight loss groups, and food products and supplements. Dietary supplements, though widely used, are not considered a healthy option for weight loss, and have no clinical evidence of efficacy. Herbal products have not been shown to be effective. In 2008, between US$33 billion and $55 billion was spent annually in the US on weight-loss products and services, including medical procedures and pharmaceuticals, with weight-loss centers taking between 6 and 12 percent of total annual expenditure. Over $1.6 billion per year was spent on weight-loss supplements. About 70 percent of Americans' dieting attempts are of a self-help nature. In Western Europe, sales of weight-loss products, excluding prescription medications, topped €1,25 billion (£900 million/$1.4 billion) in 2009. The scientific soundness of commercial diets by commercial weight management organizations varies widely, being previously non-evidence-based, so there is only limited evidence supporting their use, because of high attrition rates. Commercial diets result in modest weight loss in the long term, with similar results regardless of the brand, and similarly to non-commercial diets and standard care.
Sources: en.wikipedia.org
=== Generic names === Trazodone is the generic name of the drug and its INNTooltip International Nonproprietary Name, BANTooltip British Approved Name, and DCFTooltip Dénomination Commune Française, while trazodone hydrochloride is its USANTooltip United States Adopted Name, USPTooltip United States Pharmacopeia, BANMTooltip British Approved Name, and JANTooltip Japanese Accepted Name.
==== Other ==== Treatment of breast cancer in women, although they are now rarely used for this purpose due to their marked virilizing side effects. In low doses as a component of hormone therapy for postmenopausal and transgender women, for instance to increase energy, well-being, libido, and quality of life, as well as to reduce hot flashes. Testosterone is usually used for this purpose, although methyltestosterone is also used. Male hormonal contraception; currently experimental, but potential for use as effective, safe, reliable, and reversible male contraceptives. Assistant in the treatment of Raynaud's Phenomenon and peripheral acrocyanosis. Testosterone and other anabolics tend to be potent vasodilators, which can significantly improve bloodflow in individuals prone to vasoconstriction.
Proteomics: Large-scale study of proteins, particularly their structures and functions. Mass spectrometry techniques are used. Chemoproteomics: An array of techniques used to study protein-small molecule interactions Immunoproteomics: Study of large sets of proteins (proteomics) involved in the immune response Nutriproteomics: Identifying the molecular targets of nutritive and non-nutritive components of the diet. Uses proteomics mass spectrometry data for protein expression studies Proteogenomics: An emerging field of biological research at the intersection of proteomics and genomics. Proteomics data used for gene annotations. Structural genomics: Study of the three-dimensional structure of every protein encoded by a given genome using a combination of experimental and modeling approaches.
The announcement of a new purported clean source of energy came at a crucial time: adults still remembered the 1973 oil crisis and the problems caused by oil dependence, anthropogenic global warming was starting to become notorious, the anti-nuclear movement was labeling nuclear power plants as dangerous and getting them closed, people had in mind the consequences of strip mining, acid rain, the greenhouse effect and the Exxon Valdez oil spill, which happened the day after the announcement. In the press conference, Chase N. Peterson, Fleischmann and Pons, backed by the solidity of their scientific credentials, repeatedly assured the journalists that cold fusion would solve environmental problems, and would provide a limitless inexhaustible source of clean energy, using only seawater as fuel. They said the results had been confirmed dozens of times and they had no doubts about them. In the accompanying press release Fleischmann was quoted saying: "What we have done is to open the door of a new research area, our indications are that the discovery will be relatively easy to make into a usable technology for generating heat and power, but continued work is needed, first, to further understand the science and secondly, to determine its value to energy economics."
DiCaprio continued to gain acclaim for his performances in the biopic The Aviator (2004), the political thriller Blood Diamond (2006), the crime thriller The Departed (2006), the romantic drama Revolutionary Road (2008), the action thriller Inception (2010), the western Django Unchained (2012), the biopic The Wolf of Wall Street (2013), the survival drama The Revenant (2015)—for which he won the Academy Award for Best Actor—the comedy-drama Once Upon a Time in Hollywood (2019), the crime drama Killers of the Flower Moon (2023) and the action film One Battle After Another (2025). DiCaprio is the founder of Appian Way Productions—a production company that has made some of his films and environmental documentaries, such as the series Greensburg (2008–2010)—and the Leonardo DiCaprio Foundation, a nonprofit organization devoted to promoting environmental awareness. A United Nations Messenger of Peace, he regularly supports charitable causes. In 2005, he was named a Commander of the Order of Arts and Letters for his contributions to the arts, and in 2016, he appeared in Time magazine's 100 most influential people in the world. DiCaprio was voted one of the 50 greatest actors of all time in a 2022 readers' poll by Empire magazine.
Sources: en.wikipedia.org
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.
Dry powder is kept frozen, desiccated, and shielded from light. Dissolved material is aliquoted and frozen to limit freeze-thaw cycles. Short-term refrigerated storage is common for working solutions.
Russia registers it as a prescription nasal product. Most other markets classify it as a research chemical with no approved medical use. Oversight of purity and labeling is consequently minimal in those markets.
Selank is a synthetic peptide made of seven amino acids. It is modeled on tuftsin, a natural tetrapeptide, with an added three-residue tail. It is not a small-molecule drug.