This is a working overview of Intranasal delivery, written for readers who want more than a one-paragraph summary but less than a textbook.
Reviewed 2025-09-26. Anything still debated is marked as such rather than presented as settled.
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.
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 |
|---|---|---|
| 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 |
Reverse-phase high-performance liquid chromatography with ultraviolet detection near 214 nanometres is the standard purity method. Mass spectrometry, typically electrospray ionisation, confirms identity through the expected mass-to-charge pattern. Amino acid analysis can verify composition independently. Chiral purity requires separate techniques such as derivatisation followed by chromatographic separation, and such data are rarely reported for research-grade material.
Quantification in biological matrices relies on liquid chromatography coupled to tandem mass spectrometry with stable-isotope internal standards. Low plasma concentrations and adsorption to container surfaces both complicate measurement. Solid-phase extraction is often needed to reduce matrix interference before injection. Reported limits of quantification differ widely between laboratories, which makes direct comparison of pharmacokinetic results difficult and limits meta-analysis.
Peptide stability depends strongly on temperature, moisture, and pH. Lyophilized Selank is generally most stable when stored cold and dry, with freezer temperatures commonly used for long-term storage. In solution, the compound is susceptible to hydrolysis and to microbial growth if it is not handled aseptically. The C-terminal proline-rich extension appears to slow enzymatic cleavage relative to tuftsin, though quantitative degradation rates vary with the matrix and the conditions tested. Published stability data specific to Selank remain sparse.
Quality assessment of Selank samples typically combines purity determination with identity confirmation and counter-ion analysis. Purity is usually reported as a percentage by chromatographic area, with values above 95 percent often quoted for research-grade material. Water content and residual solvents are checked in lyophilized batches because they affect both stability and accurate mass determination. A reported purity figure does not by itself establish that a sample is the intended sequence, so orthogonal methods are needed to rule out sequence isomers or truncation products.
Characterization of Selank in laboratory settings relies on standard peptide analytical techniques. Reverse-phase high-performance liquid chromatography separates the peptide from related impurities and degradation products, while mass spectrometry confirms molecular identity through accurate mass measurement. Amino acid analysis and peptide sequencing verify the primary structure when reference material is unavailable. Because Selank is a short chain, fragmentation-based analysis produces a diagnostic ion pattern that supports confident identification.
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.
== Safety == Chloral hydrate was routinely administered in gram quantities. Prolonged exposure to its vapors is unhealthy, with an LD50 for 4-hour exposure of 440 mg/m3. Long-term use of chloral hydrate is associated with a rapid development of tolerance to its effects and possible addiction as well as adverse effects including rashes, gastric discomfort and severe kidney, heart, and liver failure. Acute overdosage is often characterized by nausea, vomiting, confusion, convulsions, slow and irregular breathing, cardiac arrhythmia, and coma. The plasma, serum or blood concentrations of chloral hydrate and/or trichloroethanol, its major active metabolite, may be measured to confirm a diagnosis of poisoning in hospitalized patients or to aid in the forensic investigation of fatalities. Accidental overdosage of young children undergoing simple dental or surgical procedures has occurred. Hemodialysis has been used successfully to accelerate clearance of the drug in poisoning victims. It is listed as having a "conditional risk" of causing torsades de pointes.
The ACS International Activities is the birthplace of the ACS International Center, an online resource for scientists and engineers looking to study abroad or explore an international career or internship. The site houses information on hundreds of scholarships and grants related to all levels of experience to promote scientific mobility of researchers and practitioners in STEM fields. The Society grants membership to undergraduates as student members provided they can pay the $25 yearly dues. Any university may start its own ACS Student Chapter and receive benefits of undergraduate participation in regional conferences and discounts on ACS publications. The American Chemical Society administers 64 national awards, medals and prizes based on scientific contributions at various career levels that promote achievement across the chemical sciences. The ACS national awards program began in 1922 with the establishment of the Priestley Medal, the highest award offered by the ACS, which is given for distinguished services to chemistry.
Hox genes play a massive role in some amphibians and reptiles in their ability to regenerate lost limbs, especially HoxA and HoxD genes. If the processes involved in forming new tissue can be reverse-engineered into humans, it may be possible to heal injuries of the spinal cord or brain, repair damaged organs and reduce scarring and fibrosis after surgery. Despite the large conservation of the Hox genes through evolution, mammals and humans specifically cannot regenerate any of their limbs. This raises a question as to why humans which also possess an analog to these genes cannot regrow and regenerate limbs. Beside the lack of specific growth factor, studies have shown that something as small as base pair differences between amphibian and human Hox analogs play a crucial role in human inability to reproduce limbs. Undifferentiated stem cells and the ability to have polarity in tissues is vital to this process.
In healthy individuals, the cortisol level should increase above 18–20 μg/dl within 60 minutes on a 250 mcg cosyntropin stimulation test. For standardization across laboratories, the Short Synacthen Test is preferably performed in the morning (between 8:00 AM and 10:00 AM) to account for the diurnal peak of cortisol secretion. Baseline cortisol is drawn at time 0, with follow‑up samples at 30 minutes (and optionally 60 minutes) after administration of 250 μg synthetic ACTH. An adequate response is generally defined as a peak serum cortisol ≥ 500–550 nmol/L (approximately 18–20 μg/dL) or an increment ≥ 200 nmol/L, thresholds that improve diagnostic accuracy for adrenal insufficiency. Interpretation for primary adrenal insufficiency, Addison's disease In Addison's disease, both the cortisol and aldosterone levels are low, and the cortisol will not rise during the cosyntropin stimulation test.
==== Dick's screenplay ==== Dick's screenplay features numerous scenes that are not in the novel. According to Tim Powers, a friend of Dick's and fellow science fiction writer, in his foreword to Ubik: The Screenplay, Dick had an idea for the film that involved "the film itself appearing to undergo a series of reversions: to black-and-white, then to the awkward jerkiness of very early movies, then to a crookedly jammed frame which proceeds to blacken, bubble and melt away, leaving only the white glare of the projection bulb, which in turn deteriorates to leave the theater in darkness, and might almost leave the moviegoer wondering what sort of dilapidated, antique jalopy he'll find his car-keys fitting when he goes outside".
Sources: en.wikipedia.org
In 2019, the European Commission announced that CBD and other cannabinoids would be classified as "novel foods", meaning that CBD products would require authorization under the EU Novel Food Regulation stating that because "this product was not used as a food or food ingredient before May 15, 1997, before it may be placed on the market in the EU as a food or food ingredient, a safety assessment under the Novel Food Regulation is required." The recommendation – applying to CBD extracts, synthesized CBD, and all CBD products, including CBD oil – was scheduled for a final ruling by the European Commission in March 2019. If approved, manufacturers of CBD products would be required to conduct safety tests and prove safe consumption, indicating that CBD products would not be eligible for legal commerce until at least 2021. In December 2020, the European Commission concluded that CBD should not be considered as drug and can be qualified as food. Cannabidiol is listed in the EU Cosmetics Ingredient Database (CosIng). However, the listing of an ingredient, assigned with an INCI name, in CosIng does not mean it is to be used in cosmetic products or is approved for such use. Several industrial hemp varieties can be legally cultivated in Western Europe. A variety such as "Fedora 17" has a cannabinoid profile consistently around 1%, with THC less than 0.3%.
=== Sixth Form === Woodhouse Grammar School was later reconstituted as Woodhouse Sixth Form College. There were plans to merge the school with Friern Barnet County Secondary School in 1971, but these were blocked by local MP Margaret Thatcher. Thatcher gave a speech at the college in May 1983. In January 2021 Woodhouse College converted to academy status and is now part of the Frontier Learning Trust.
Dalbergia odorifera, fragrant rosewood or Chinese rosewood, is a species of true rosewood in the genus Dalbergia. It is a small or medium-sized tree, 10–15 metres (33–49 ft) tall. It is endemic to China and occurs in Fujian, Hainan, Zhejiang, and Guangdong.
==== Banking ==== Peru's financial sector is characterized by a lack of credit, as 70% of Peruvians are unbanked or underbanked. Following complaints of loan sharks that charge rates up to 200%, Castillo has sought to improve competition by allowing public banks to compete with private banks. Additionally, Castillo has allowed additional foreign banks to enter the Peruvian market.
== Early life and education == Philip E. Dawson obtained his bachelor's degree in chemistry from Washington University in St. Louis, graduating magna cum laude. He went on to earn his Ph.D. in chemistry from Scripps Research in 1996. Following his doctoral studies, Dawson conducted postdoctoral research at the California Institute of Technology before returning to Scripps Research as an assistant professor.
Sources: en.wikipedia.org
=== Dependence === Opioid dependence can occur as physical dependence, psychological dependence, or both. Drug dependence is an adaptive state associated with a withdrawal syndrome upon cessation of repeated exposure to a stimulus (e.g., drug intake). Dependence is a component of a substance use disorder. Opioid dependence can manifest as physical dependence, psychological dependence, or both. Increased brain-derived neurotrophic factor (BDNF) signaling in the ventral tegmental area (VTA) has been shown to mediate opioid-induced withdrawal symptoms via downregulation of insulin receptor substrate 2 (IRS2), protein kinase B (AKT), and mechanistic target of rapamycin complex 2 (mTORC2). As a result of downregulated signaling through these proteins, opiates cause VTA neuronal hyperexcitability and shrinkage (specifically, the size of the neuronal soma is reduced). It has been shown that when an opiate-naive person begins using opiates in concentrations that induce euphoria, BDNF signaling increases in the VTA. Upregulation of the cyclic adenosine monophosphate (cAMP) signal transduction pathway by cAMP response element binding protein (CREB), a gene transcription factor, in the nucleus accumbens is a common mechanism of psychological dependence among several classes of drugs of abuse. Upregulation of the same pathway in the locus coeruleus is also a mechanism responsible for certain aspects of opioid-induced physical dependence. A scale was developed to compare the harm and dependence liability of 20 drugs.
Methionitazene (methylthionitazene) is a benzimidazole derivative which is an opioid designer drug. It was invented in the late 1950s as part of the original research into the "nitazene" group of opioids by CIBA in Switzerland, but as with all compounds from this group was never developed for legitimate medical uses. In early studies on mice, it was found to be around half the potency of the methoxy analogue metonitazene with around 50 times the analgesic potency of morphine, and significantly more potent than the ethylthio homologue, but more recent research using modern techniques found methionitazene and metonitazene to have a similar EC50 in vitro despite the methoxy compound having a stronger binding affinity at the mu opioid receptor.
== Honours and awards == Borchers' contributions to proteomics have been recognized with fellowship in the Canadian Academy of Health Sciences (2013), the Genome BC Award for Scientific Excellence from Life Sciences British Columbia (2016), and the Canadian Society for Mass Spectrometry's Fred P. Lossing Award (2023), given for outstanding contributions to the field of mass spectrometry.
=== Central pattern generators === Central pattern generators are groups of neurons in the spinal cord that are responsible for generating stereotyped movement. It has been shown that in cats, rhythmic activation patterns are still observed following removal of sensory afferents and removal of the brain, indicating that there is neural pattern generation in the spinal cord independent of descending signals from the brain and sensory information. It is currently understood that the spinal cord receives sensory input from proprioceptive organs and descending commands from the brain, integrates these signals, and sends activation signals to muscle through alpha motoneurons and fusimotor signals through gamma motoneurons in a coordinated and rhythmic fashion.
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.
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.