Intranasal delivery comes up often in conversation and rarely with the context attached. Here we lay out the basics in order, then work through the practical considerations.
Updated 2026-04-13. Numbers and descriptions here follow the published literature rather than marketing material.
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.
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.
| 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 |
Selank is a synthetic heptapeptide with the sequence Thr-Lys-Pro-Arg-Pro-Gly-Pro, written TKPRPGP in one-letter notation. Its structure consists of the immunomodulatory tetrapeptide tuftsin, Thr-Lys-Pro-Arg, extended at the carboxyl terminus by a Pro-Gly-Pro segment. The molecular formula is commonly given as C33H57N11O9, corresponding to a monoisotopic mass near 751.4 Da and an average molecular mass near 751.9 Da. All seven residues are proteinogenic amino acids, and the molecule carries no modified side chains or non-natural linkages.
The compound was designed at the Institute of Molecular Genetics of the Russian Academy of Sciences during the 1980s and 1990s. The stated design goal was to retain the immunomodulatory and central nervous system activity attributed to tuftsin while improving resistance to enzymatic breakdown. Adding a proline-rich tail to the short parent peptide was a deliberate strategy, because proline residues restrict the conformations available to many peptidases. The same laboratory produced Semax, an ACTH fragment analog, and both compounds were developed in parallel as short, enzymatically stabilized peptides intended for intranasal use.
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.
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.
Ultralente insulin was a long-acting form of medical insulin, but not a true analogue. It had an onset of 4 to 6 hours, a peak effect between 14 and 24 hours, and a duration of 28 to 36 hours. In the mid-2000s, ultralente insulin, along with lente insulin, was discontinued in the United States due to decreasing use in favor of NPH insulin and newer insulin products. By 2011, the U.S. Food and Drug Administration (FDA) had officially withdrawn approval for ultralente insulin products.
These numbers may be low due to insufficient food intake data. The concentrations of nicotine in vegetables are difficult to measure accurately, since they are very low (parts per billion range). The biological function of nicotine in the tobacco plant is as an antiherbivore neurotoxin. Some species have evolved resistance to nicotine, such as Manduca sexta. In the tobacco plant, it is produced in the roots, then transported to the leaves. It has little effect on the plant itself. Grafting the top of a tomato plant to a tobacco root does not harm the tomato plant despite accumulating nicotine in the leaves. Conversely, grafting the top of a tobacco plant to a tomato root does not harm the tobacco plant, despite not receiving nicotine.
=== Intravenous fluids === In those with poor tissue perfusion, boluses of isotonic crystalloid solution should be given. In children with more than 10–20% TBSA (Total Body Surface Area) burns, and adults with more than 15% TBSA burns, formal fluid resuscitation and monitoring should follow. This should be begun pre-hospital if possible in those with burns greater than 25% TBSA. The Parkland formula can help determine the volume of intravenous fluids required over the first 24 hours. The formula is based on the affected individual's TBSA and weight. Half of the fluid is administered over the first 8 hours, and the remainder over the following 16 hours. The time is calculated from when the burn occurred, and not from the time that fluid resuscitation began. Children require additional maintenance fluid that includes glucose. Additionally, those with inhalation injuries require more fluid. While inadequate fluid resuscitation may cause problems, over-resuscitation can also be detrimental. The formulas are only a guide, with infusions ideally tailored to a urinary output of >30 mL/h in adults or >1mL/kg in children and mean arterial pressure greater than 60 mmHg. While lactated Ringer's solution is often used, there is no evidence that it is superior to normal saline. Crystalloid fluids appear just as good as colloid fluids, and as colloids are more expensive they are not recommended. Blood transfusions are rarely required. They are typically only recommended when the hemoglobin level falls below 60-80 g/L (6-8 g/dL) due to the associated risk of complications.
=== Natural toxins === Several foods can naturally contain toxins, many of which are not produced by bacteria. Plants in particular may be toxic; animals which are naturally poisonous to eat are rare. In evolutionary terms, animals can escape being eaten by fleeing; plants can use only passive defenses such as poisons and distasteful substances, for example capsaicin in chili peppers and pungent sulfur compounds in garlic and onions. Most animal poisons are not synthesised by the animal, but acquired by eating poisonous plants to which the animal is immune, or by bacterial action.
Sources: en.wikipedia.org
Treponema pallidum was first microscopically identified in syphilitic chancres by Fritz Schaudinn and Erich Hoffmann at the Charité in Berlin in 1905. Historically, this bacterium was identified in the clinical laboratory through visualization in dark-field microscopy. This bacterium can be detected with special stains, such as the Dieterle stain. T. pallidum is also detected by serology, including nontreponemal VDRL, rapid plasma reagin, treponemal antibody tests (FTA-ABS), T. pallidum immobilization reaction, and syphilis TPHA test.
== Creationism == A Methodist from age ten, and later a fundamentalist Baptist, Gish believed that the Genesis creation narrative was historical fact. After reading the booklet Evolution, "Science Falsely So-called" in the late 1950s, Gish became persuaded that science had produced falsifiable evidence against evolutionary theory, particularly the origin of life, and that various fields of science offered corroborating evidence in support of the Genesis creation narrative. He joined the American Scientific Affiliation (ASA), an association of Christian scientists, mistakenly assuming the group supported creationism. Through his affiliation at the ASA, Gish met geneticist and creationist William J. Tinkle, who in 1961 invited Gish to join a newly formed anti-evolution caucus within the ASA. In 1971, Gish became a member of the faculty at San Diego Christian College, working in its research division before accepting a position at the Institute for Creation Research (independent since 1981). He was the author of several books and articles espousing creationism. His best-known work, Evolution: The Fossils Say No!, published in 1972, has been widely accepted by creationists as an authoritative reference. Gish initially "assigned low priority to the question of [the] age [of the Earth]". At his death on March 5, 2013, Gish held the position of Senior Vice-President Emeritus at the ICR.
== Clinical significance == Homozygous mutations, heterozygous compound (bi-allelic) mutations or haploinsufficiency in TN-X cause classical-like Ehlers–Danlos syndrome (EDS), a rare and hereditary connective tissue disorder in mice and humans. This pathology is characterized by skin hyperlaxity, joint hypermobility and global tissue weakness as a consequence of elastin fragmentation and reduced collagen density, especially in skin.
Sources: en.wikipedia.org
==== Texas ==== In February 2022, Texas Attorney General Ken Paxton initiated an investigation into TikTok for alleged violations of children's privacy and facilitation of human trafficking. Paxton claimed that the Texas Department of Public Safety gathered several pieces of content showing the attempted recruitment of teenagers to smuggle people or goods across the Mexico–United States border. He claimed the evidence may prove the company's involvement in "human smuggling, sex trafficking and drug trafficking". The company claimed that no illegal activity of any kind is supported on the platform.
The King's College Criteria or the King's College Hospital criteria were devised in 1989 to determine if there were any early indices of poor prognosis in patients with acute liver failure. Acute liver failure is defined as the onset of encephalopathy (altered mental status) or coagulopathy (altered bleeding tendencies) within 26 weeks of a patient diagnosed with liver disease. Patients with hepatitis B acquired at birth, Wilson's disease and autoimmune hepatitis are included if their disease was identified within the past 26 weeks. These patients are very ill, and have a very high risk of dying of their illness without adequate treatment which may include liver transplantation. It is important that physicians find ways of identifying patients with acute liver failure early in their course who will do poorly, and may require liver transplantation. The King's College Criteria have consistently shown excellent operating characteristics for determining prognosis in these patients. As liver transplantation becomes a more accessible option for patients with acute liver failure, the King's College Criteria serve a role in determining which patients may require transplantation.
== Research == Neural drug delivery is the next step beyond the basic addition of growth factors to nerve guidance conduits. Drug delivery systems allow the rate of growth factor release to be regulated over time, which is critical for creating an environment more closely representative of in vivo development environments.
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.
The most common approach combines reverse-phase liquid chromatography with mass spectrometry. Chromatography separates the components while mass spectrometry confirms the molecular mass. Peptide sequencing or tandem mass analysis can further verify the amino acid order.