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.
Last reviewed on 2026-08-01. Where a claim depends on a specific study, the study is described rather than over-claimed.
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.
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.
The compound has a calculated molecular weight near 751.9 daltons and carries a net positive charge at physiological pH because of its arginine residue. It dissolves freely in water and in common aqueous buffers, and typically appears as a white or off-white lyophilized powder. The amide backbone makes the molecule susceptible to peptidases, which limits oral use and favors intranasal or parenteral routes. Nomenclature in the literature varies: the substance is also described by the sequence abbreviation TP-7 and by a Russian trade designation.
Regulatory status differs sharply by region. Selank holds a Russian marketing authorization, where it is supplied mainly as nasal drops, while authorities elsewhere have not approved it for medical use. Material sold internationally is therefore usually labeled as a research chemical rather than a medicine. Peer-reviewed publications come predominantly from Russian laboratories, and sample sizes are generally small. Whether the compound produces comparable effects under independent, well-controlled replication remains an open question that the broader literature has not settled.
| Property | Value | Notes |
|---|---|---|
| Route studied | Intranasal | Predominant route in published reports |
| Circulation stability | Short, minutes scale | Peptidases cleave it; the tail slows the process |
| Analytical method | RP-HPLC with mass spectrometry | Used for identity and purity assessment |
| Reported outcome domains | Anxiety and cognitive measures | Derived from small, mostly regional trials |
| Regulatory status | Marketed in Russia | Availability outside that market is limited |
Reported pharmacological effects center on reduced anxiety-like behavior in animal models and on measures of memory and learning. Proposed contributing mechanisms include modulation of GABAergic signaling, shifts in monoamine turnover, and changes in the activity of enzymes that degrade neuropeptides. Effects on the expression of genes linked to neuroplasticity have also been described. No single molecular target is widely accepted, and whether the behavioral findings arise from one pathway or several remains an open question.
Selank is a synthetic heptapeptide with the sequence Thr-Lys-Pro-Arg-Pro-Gly-Pro. It was designed as a stabilized analogue of tuftsin, a naturally occurring tetrapeptide fragment derived from the immunoglobulin heavy chain. The additional Pro-Gly-Pro segment at the carboxyl terminus is intended to slow enzymatic cleavage. The compound is usually described in the literature as a synthetic peptide with anxiolytic and cognitive-related activity, a label that reflects a research context rather than an approved therapeutic category.
Most published work on selank originates from a small number of research groups in the Russian Federation. A large share of that record appears in Russian-language journals, which limits access for readers who rely on English-indexed databases. Independent replication by laboratories outside the original research network is sparse in publicly available sources. This concentration of origin and language is a frequently noted feature when the compound is summarized in broader reviews of synthetic peptides.
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.
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.
He claimed that on 3 August the third side began to participate in the clashes between the Georgian and South Ossetian forces, firing on both the Georgians and South Ossetians. Illarionov said that the Ossetians do not deny the Georgian reports that the Ossetians violated the ceasefire declared on 7 August by Saakashvili. According to him, by August 2008 South Ossetia had become the most militarised territory per capita in the world, surpassing even North Korea. He also said that the Georgians apparently did not have any plan to invade South Ossetia, only a plan to defend the Georgian villages in South Ossetia. In November 2008, Russian organisation Memorial said there was abundant evidence of mutual shelling before 7 August 2008. The head of Memorial, Oleg Orlov, was in South Ossetia and Georgia for two weeks. He said that firing started on August 1 along the Georgian-South Ossetian border. Orlov said that South Ossetians had attacked Georgian civilians inside South Ossetia and they had used the Tskhinvali headquarters of Russian peacekeeping force as their base. Orlov said that Russia had provoked the Georgian military operation. He added, "But Russian peacekeepers also didn't do their job properly. We know the Russian side gave arms to the Ossetians and that they used them to fire towards Georgia from Russian peacekeeping positions well before August 7." Orlov reported that Russia had begun building the road connecting Tskhinvali with Akhalgori in the spring 2008, long before the war, and it was already completely finished.
== External links == Pharmaceutical Inspection Cooperation Scheme: GMP Guides World Health Organization GMP Guidelines European Union GMP Guidelines US CFR Title 21 parts 210 (GMP, general), 211 (GMP, finished pharmaceuticals), 212 (GMP, positron emission tomography drugs), 225 (GMP, medicated feeds), 226 (GMP, type A medicated articles). Report on Optimizing and Leaning GMP Batch Record Design
Octreotide, sold under the brand name Sandostatin among others, is an octapeptide that mimics natural somatostatin pharmacologically, though it is a more potent inhibitor of growth hormone, glucagon, and insulin than the natural hormone. It was first synthesized in 1979 and binds predominantly to the somatostatin receptors SSTR2 and SSTR5. It was approved for use in the United States in 1988. Octreotide was approved for medical use in the European Union in 2022. As of June 2020, octreotide is the first oral somatostatin analog (SSA) approved by the FDA. It is on the World Health Organization's List of Essential Medicines.
== Cancer resistance to immunotherapy == While immunotherapy has provided a tool for combating cancer, a significant clinical challenge comes with it. Cancer cells can develop resistance to immunotherapy treatment, which decreases the efficacy of the treatment. A substantial proportion of patients either begin treatment with resistance, causing failure in response, or develop resistance after the medication is administered. A recent review estimated that a majority of patients with solid tumors eventually acquire resistance to immunotherapy. Resistance to immunotherapy falls under either the category of primary or innate resistance, which causes a lack of response to immunotherapy treatment from the get-go, or acquired resistance, where there is an initial positive response to treatment followed by regression. Resistance arises through mechanisms that alter the interaction between tumor cells, the immune system, and the tumor microenvironment. Tumor antigenicity, or the ability for the immune system to recognize cancer cells, is a primary target for resistance. Resistance mutations that down-regulate (decrease) the expression of antigen-presenting factors allow the immune system to ignore the presence of cancer cells. The major histocompatibility complex (MHC), which presents antigens on the cell surface to prompt immune recognition, is often a target. When T cells can no longer identify malignant cells, this renders therapies and immune recognition useless. A second mechanism of immunotherapy resistance is impaired immune cell function.
Sources: en.wikipedia.org
From a total of around 7,000 species, only about 150 species are widely distributed around the world. These are the peregrine or cosmopolitan earthworms. Of the 308 taxa of earthworms found in the United States and Canada, 70 (23%) are introduced species.
=== Fast === Fast COLD-PCR differs from Full COLD-PCR in that the denaturation and intermediate annealing stages are skipped. This is because, in some cases, the preferential amplification of the mutant DNA is so great that ensuring the formation of the mutant/wildtype heteroduplex DNA is not needed. Thus the denaturation can occur at the Tc, proceed to primer annealing, and then polymerase-mediated extension. Each round of amplification will include these three stages in that order. By utilizing the lower denaturation temperature, the reaction will discriminate toward the products with the lower Tm – i.e. the variant alleles. Fast COLD-PCR produces much faster results due to the shortened protocol, while Full COLD-PCR is essential for amplification of all possible mutations in the starting mixture of DNA. Two-round COLD-PCR is a modified version of Fast COLD-PCR. During the second round of Fast COLD-PCR nested primers are used. This improves the sensitivity of mutation detection compared to one-round Fast COLD-PCR.
=== Electrical conductivity and electrolysis === Pure water has a low electrical conductivity, which increases with the dissolution of a small amount of ionic material such as common salt. Liquid water can be split into the elements hydrogen and oxygen by passing an electric current through it—a process called electrolysis. The decomposition requires more energy input than the heat released by the inverse process (285.8 kJ/mol, or 15.9 MJ/kg).
Insulin resistance (IR) is a pathological response in which cells in insulin-sensitive tissues in the body fail to respond normally to the hormone insulin or downregulate insulin receptors in response to hyperinsulinemia. Insulin resistance is a major cause of type 2 diabetes. Insulin is a hormone that facilitates the transport of glucose from blood into cells, thereby reducing blood glucose (blood sugar). Insulin is released by the pancreas in response to carbohydrates consumed in the diet. In states of insulin resistance, the same amount of insulin does not have the same effect on glucose transport and blood sugar levels. There are many causes of insulin resistance and the underlying process is still not completely understood. Risk factors for insulin resistance include obesity, sedentary lifestyle, family history of diabetes, various health conditions, and certain medications. Insulin resistance is considered a component of the metabolic syndrome. Insulin resistance can be improved or reversed with lifestyle approaches, such as weight reduction, exercise, and dietary changes. Techniques to test for the presence or extent of insulin resistance include measurement of fasting insulin levels, the hyperinsulinemic euglycemic clamp technique, the modified insulin suppression test and static function tests. These methods are not often used in clinical practice.
=== Circadian rhythm sleep disorders === Melatonin may be useful in the treatment of delayed sleep phase syndrome. Melatonin is known to reduce jet lag, especially in eastward travel. However, if it is not taken at the correct time, it can instead delay adaptation. Melatonin appears to have limited use against the sleep problems of people who work shift work. Tentative evidence suggests that it increases the length of time people are able to sleep. Meta-analyses, published between 2005 and 2017, appear to show different results as to whether melatonin is effective for circadian rhythm sleep disorders or not. Some found that it was effective, while others found no evidence of effectiveness. Meta-analyses of melatonin for delayed sleep phase syndrome that found it effective have reported that it improves time to sleep onset by about 40 minutes (0.67 hours) and advances onset of endogenous melatonin secretion by about 1.2 hours (72 minutes). One meta-analysis found that melatonin was notably more effective in improving sleep onset latency in people with delayed sleep phase syndrome than in people with insomnia (improvement of 39 minutes vs. 7 minutes, respectively). One meta-analysis found that melatonin was probably effective for jet lag syndrome.
Sources: en.wikipedia.org
Reports describe effects on GABA-A receptor expression, monoamine turnover, and neurotrophic factor levels. These are proposed mechanisms drawn mainly from animal models. No single molecular target has been established.
Intranasal delivery is the route described in most published work. It is used because the peptide is degraded quickly once it reaches circulation. Direct evidence of brain penetration in humans is lacking.
Most trials are small, regionally concentrated, and often lack rigorous blinding or placebo control. Independent replication is limited. Reviews in English generally rate the evidence as preliminary.
Selank is a synthetic seven-amino-acid peptide modeled on tuftsin, a fragment of the immunoglobulin G heavy chain. It was designed in Russia to combine anxiolytic and immunomodulatory properties in one molecule.