If you have been reading about intranasal delivery and want a single page that covers the useful parts, this is it: definitions, context, how it is studied, and the questions that come up repeatedly.
Last reviewed on 2025-09-03. Where a claim depends on a specific study, the study is described rather than over-claimed.
Published research covers ischemic stroke, traumatic brain injury, cognitive impairment, optic nerve conditions and attention-related measures. Much of the human evidence comes from small trials conducted in one country, which limits how far the results generalize. Animal models supply the larger share of the data, and effects seen in rodents do not transfer automatically to people. Reviews have noted that methodological reporting is often incomplete, making it difficult to pool results or compare treatment schedules across studies.
Pharmacokinetic accounts emphasize rapid breakdown. After intravenous dosing the intact peptide disappears from blood within minutes, and nasal delivery produces low but measurable concentrations. Metabolites rather than the parent molecule may account for part of the observed activity, although the relative contribution is unresolved. Dosing in the literature varies widely and no optimal schedule has been agreed. These gaps are regularly cited as a reason the findings have not produced broad clinical adoption beyond the original research setting.
Proposed mechanisms center on neurotrophic signaling rather than on classical melanocortin receptor activation. Rodent experiments have reported shifts in the expression of brain-derived neurotrophic factor and nerve growth factor after administration, together with changes in the associated receptor systems. Several authors argue that the peptide acts largely through its degradation products and their interaction with peptidergic pathways, but this remains a hypothesis rather than a settled finding. No single molecular target has been identified in a way that the field broadly accepts.
Regulatory status differs sharply between jurisdictions. In Russia the peptide is registered as a prescription nasal preparation, while agencies such as the United States Food and Drug Administration have not approved it for any indication. Products sold elsewhere are typically labeled for laboratory research only, and such labels shift responsibility for safe handling to the purchaser. Because the same name covers pharmaceutical-grade nasal drops and bulk research powder, identity and purity documentation becomes the main practical concern when comparing sources.
Semax is a synthetic seven-amino-acid peptide whose sequence extends the ACTH(4-10) fragment with a C-terminal proline-glycine-proline tripeptide. The commonly cited sequence is Met-Glu-His-Phe-Pro-Gly-Pro, giving a molecular formula near C37H51N9O10S and a molecular weight close to 813.9 g/mol. It belongs to the broader class of synthetic ACTH fragments studied for central nervous system effects rather than for adrenal steroid stimulation. In practice the material appears as a lyophilized white powder for laboratory work or as a dilute saline solution in clinical settings.
Development is attributed to researchers at the Institute of Molecular Genetics in Moscow during the early 1980s, building on earlier Soviet work with ACTH fragments. Russian regulatory approval followed for intranasal use, and the compound has remained commercially available there for decades. Most published human data originate from Russian and, later, some Eastern European clinical reports, which are not always accessible in English translation. Outside that region the material is generally handled as a research chemical rather than a licensed medicine.
| Property | Value | Notes |
|---|---|---|
| Primary research models | Rodent studies | Largest share of published data |
| Reported markers | BDNF and NGF expression | Measured mainly in animal tissue |
| Common administration | Intranasal | Matches the registered formulation |
| Blood residence time | Minutes | Rapid enzymatic degradation |
| Evidence quality | Small trials, limited replication | Noted repeatedly in reviews |
Verification of a supplied batch generally combines a certificate of analysis with independent testing, because certificates are self-reported documents. A typical package includes a chromatographic trace, a mass spectrum, and a stated water or counter-ion content. Batch-to-batch consistency matters more than a single purity figure when results are compared across experiments. No single mandatory standard governs research-grade peptide release, so laboratories are expected to define their own acceptance criteria. Residual trifluoroacetate from purification is a frequently overlooked counter-ion.
Lyophilized material is chemically stable for extended periods when kept dry, cold, and protected from light. The powder is hygroscopic, so vials should be warmed to room temperature before opening to reduce condensation on the contents. Once dissolved, the peptide is far less stable because peptide bonds are susceptible to hydrolysis and the methionine residue can oxidize. Solutions are typically aliquoted and held at 2-8 °C for short intervals or frozen for longer ones, and repeated freeze-thaw cycles should be avoided.
Reported pharmacological work centers on neurotrophic signaling, including changes in BDNF and NGF expression in hippocampal tissue in animal models. Human data come largely from studies conducted in Russia, and how well those results generalize to other populations remains an open question. Regulatory status differs sharply by jurisdiction: Semax is a registered prescription medicine in Russia, while it holds no approved marketing status in the United States or the European Union. Outside such jurisdictions it is generally handled as a research chemical, which affects both documentation and quality expectations.
Semax is a synthetic heptapeptide whose sequence is Met-Glu-His-Phe-Pro-Gly-Pro. It was developed as a fragment analog of adrenocorticotropic hormone, modeled specifically on the ACTH(4-10) region. The first four residues reproduce that fragment, while a Pro-Gly-Pro tripeptide is appended at the C-terminus. Work on the compound originated in Russia, where it entered clinical use as an intranasal preparation. Its sequence places it among short regulatory peptides studied for effects on the central nervous system rather than on the adrenal axis.
The C-terminal Pro-Gly-Pro extension is not incidental. Proline-rich tails are known to resist several common peptidases, and the published literature attributes the longer half-life of Semax, relative to unmodified ACTH fragments, to this feature. The modification also removes the melanocyte-stimulating and corticosteroidogenic activity that characterizes longer ACTH-derived sequences. Because the molecule is small and hydrophilic, it is typically formulated as an aqueous solution for intranasal or parenteral delivery. Acetylation or amidation at the termini appears in closely related research peptides and shifts the mass by a fixed increment.
Published research has focused mainly on neurological and cognitive endpoints in animal models, with proposed mechanisms involving brain-derived neurotrophic factor and related signalling pathways. A substantial share of the human data originates from a limited number of research groups, and independent replication in other countries remains sparse. Regulatory status reflects that distribution: the peptide is registered as a medicine in Russia and appears in some neighbouring markets, while elsewhere it is handled as a research chemical without approved therapeutic labelling. Questions about dose-response relationships, long-term effects, and comparability across studies are still open.
Lyophilised powder is normally kept at -20 °C in a desiccated container, with some suppliers recommending -80 °C for long-term archival storage. Repeated freeze-thaw cycles are the most common cause of avoidable loss, so aliquoting before freezing reduces variability between working sessions. Dissolved peptide is far less stable than the dry solid and is usually prepared fresh or held briefly at 4 °C. Aqueous solutions support both hydrolysis of the backbone and oxidation of the N-terminal methionine, and these two routes dominate degradation under ordinary laboratory conditions.
Identity and purity are confirmed with reversed-phase high-performance liquid chromatography, typically monitored at 214 nanometres where the peptide bond absorbs. Mass spectrometry, either electrospray or MALDI-TOF, verifies molecular mass against the theoretical value and detects truncation or adduct formation. Amino acid analysis and peptide mapping provide additional confirmation when required. The most frequently reported impurities are deletion sequences from incomplete coupling, methionine sulfoxide from oxidation, and dimeric species formed through non-covalent aggregation. Impurity profiles depend strongly on the synthesis and purification route chosen by the producer.
==== MeSH D12.776.624.776.355 – cyclin-dependent kinase inhibitor proteins ==== MeSH D12.776.624.776.355.100 – cyclin-dependent kinase inhibitor p15 MeSH D12.776.624.776.355.200 – cyclin-dependent kinase inhibitor p16 MeSH D12.776.624.776.355.300 – cyclin-dependent kinase inhibitor p18 MeSH D12.776.624.776.355.400 – cyclin-dependent kinase inhibitor p19 MeSH D12.776.624.776.355.500 – cyclin-dependent kinase inhibitor p21 MeSH D12.776.624.776.355.600 – cyclin-dependent kinase inhibitor p27 MeSH D12.776.624.776.355.700 – cyclin-dependent kinase inhibitor p57
Fentanyl is contributing to an epidemic of synthetic opioid drug overdose deaths in the United States. From 2011 to 2021, overdose deaths involving prescription opioid (natural and semi-synthetic opioids and methadone) per year remained stable, while synthetic opioid (primarily fentanyl) associated overdose deaths per year increased from 2,600 overdoses to 70,601. Fentanyl was involved in the most drug overdose deaths in the United States in 2018. The United States National Forensic Laboratory estimates fentanyl reports by federal, state, and local forensic laboratories increased from 4,697 reports in 2014 to 117,045 reports in 2020. Fentanyl is often mixed, cut, or ingested alongside other drugs, including cocaine and heroin. Fentanyl has been reported in pill form, including pills mimicking pharmaceutical drugs such as oxycodone. Mixing with other drugs or disguising as a pharmaceutical makes it difficult to determine the correct treatment in the case of an overdose, resulting in more deaths. Emerging adulterants have further complicated the evolving fentanyl supply. In an attempt to reduce the number of overdoses from taking other drugs mixed with fentanyl, drug testing kits, strips, and labs are available.
Dyspnea on exertion Peripheral edema and ascites Pericardial effusion Arrhythmias (secondary to disruption of the normal electrical system of the heart) Atrial arrhythmias (such as atrial fibrillation) First/second degree heart blocks Syncope Elevated neck veins and jugular venous pressure Myocardial ischemia/angina (secondary to amyloid deposition in the coronary arteries of the heart) Myocardial oxygen demand is increased in patients with cardiac amyloidosis, regardless of changes to coronary perfusion. For patients with light-chain amyloidosis, there can be depositions of amyloid into numerous different organs. Deposition of amyloid into other organs makes the diagnosis of cardiac amyloidosis difficult as these extracardiac manifestations mask the diagnosis. Extracardiac manifestations include:
== General Principles in Infants/Children Immunization == Because measles kills, every infant needs to be vaccinated against measles at the age of 9 months or as soon as possible after 9 months as part of the routine infant vaccination schedule. It is safe to vaccinate a sick child who is suffering from a minor illness (cough, cold, diarrhea, fever or malnutrition) or who has already been vaccinated against measles. If the vaccination schedule is interrupted, it is not necessary to restart. Instead, the schedule should be resumed using minimal intervals between doses to catch up as quickly as possible. Vaccine combinations (few exceptions), antibiotics, low-dose steroids (less than 20 mg per day), minor infections with low fever (below 38.5º Celsius), diarrhea, malnutrition, kidney or liver disease, heart or lung disease, non-progressive encephalopathy, well controlled epilepsy or advanced age, are not contraindications to vaccination. Contrary to what the majority of doctors may think, vaccines against hepatitis B and tetanus can be applied in any period of the pregnancy. There are very few true contraindication and precaution conditions. Only two of these conditions are generally considered to be permanent: severe (anaphylactic) allergic reaction to a vaccine component or following a prior dose of a vaccine, and encephalopathy not due to another identifiable cause occurring within 7 days of pertussis vaccination. Only the diluent supplied by the manufacturer should be used to reconstitute a freeze-dried vaccine.
== 3D holograms == In 1976, he became the holography assistant for the American new media artist Al Razutis. In 1978 he received Canadian government funding to build his own holography studio and study holographic special effects. He exhibited the results of this work in Vancouver at the Helen Pitt Gallery in June 1978 and again in Victoria at the Open Space Gallery in June 1979.
Sources: en.wikipedia.org
=== Nationality and travel history === Many nations implement border controls restricting the entry of people of certain nationalities or who have visited certain countries. For instance, Georgia refuses entry to holders of passports issued by the Republic of China. Similarly, since April 2017, nationals of Bangladesh, Pakistan, Sudan, Syria, Yemen, and Iran have been banned from entering the parts of eastern Libya under the control of the Tobruk government. The majority of Arab countries, as well as Iran and Malaysia, ban Israeli citizens, however exceptional entry to Malaysia is possible with approval from the Ministry of Home Affairs. Certain countries may also restrict entry to those with Israeli stamps or visas in their passports. As a result of tension over the Artsakh dispute, Azerbaijan currently forbids entry to Armenian citizens as well as to individuals with proof of travel to Artsakh. Between September 2017 and January 2021, the United States did not issue new visas to nationals of Iran, North Korea, Libya, Somalia, Syria, or Yemen pursuant to restrictions imposed by the Trump administration, which were subsequently repealed by the Biden administration on 20 January 2021. While in force, the restrictions were conditional and could be lifted if the countries affected meet the required security standards specified by the Trump administration, and dual citizens of these countries could still enter if they presented a passport from a non-designated country.
Radon is an invisible, radioactive atomic gas that results from the radioactive decay of radium, which may be found in rock formations beneath buildings or in certain building materials themselves. Radon is probably the most pervasive serious hazard for indoor air in the United States and Europe. It is a major cause of lung cancer, responsible for 3–14% of cases in countries, leading to tens of thousands of deaths. Radon gas enters buildings as a soil gas. As it is a heavy gas it will tend to accumulate at the lowest level. Radon may also be introduced into a building through drinking water particularly from bathroom showers. Building materials can be a rare source of radon, but little testing is carried out for stone, rock or tile products brought into building sites; radon accumulation is greatest for well insulated homes. There are simple do-it-yourself kits for radon gas testing, but a licensed professional can also check homes. The half-life for radon is 3.8 days, indicating that once the source is removed, the hazard will be greatly reduced within a few weeks. Radon mitigation methods include sealing concrete slab floors, basement foundations, water drainage systems, or by increasing ventilation. They are usually cost effective and can greatly reduce or even eliminate the contamination and the associated health risks. Radon is measured in picocuries per liter of air (pCi/L) or becquerel per cubic meter (Bq m-3). Both are measurements of radioactivity. The World Health Organization (WHO) sets the ideal indoor radon levels at 100 Bq/m-3.
==== Public relations ==== On 26 September 2008, in order to quell the disquiet over the speech by Zhu Yonglan of the CGOSFSC regarding leaders' insulation from the food-security issues faced by the general population, Xinhua issued a brief statement, in Chinese, denying the existence of the centre, the award, or any person named Zhu Yonglan, saying these were "purely rumours". On 16 September, the AQSIQ tests on baby milk powder produced by 109 companies showed 69 batches from 22 companies to be melamine-contaminated; the State Council attempted to reassure that formula produced by most companies in China was safe. It said: "the number of companies with melamine-tainted milk accounted for 20.18% of the total of powdered milk companies in China; the number of tainted batches accounted for 14.05% of the total batches tested." On 30 September, the AQSIQ said its tests on 265 batches from 154 companies showed that "only 18%" had tested positive for melamine: "of the 290 dairies nationwide 154 dairies, representing 87% market share, 134 of these dairies had tested negative for melamine." On 16 September, the AQSIQ published results of tests on 408 liquid milk producers, and found "most dairy products were safe to drink", although the test results showed nearly 10 percent of batches from Mengniu, Yili and Bright were contaminated.
== Applications == DNA sequencing can be used to determine the sequence of individual genes, larger genetic regions (i.e. clusters of genes or operons), full chromosomes, or entire genomes of any organism. DNA sequencing is also the most efficient way to indirectly sequence RNA or proteins (via their open reading frames). In fact, DNA sequencing has become a key technology in many areas of biology and other sciences such as medicine, forensics, and anthropology.
An essential amino acid is an amino acid that is required by an organism but cannot be synthesized de novo by it, and therefore must be supplied in its diet. Out of the twenty standard protein-producing amino acids, nine cannot be endogenously synthesized by humans: phenylalanine, valine, threonine, tryptophan, methionine, leucine, isoleucine, lysine, and histidine.
Sources: en.wikipedia.org
Most serotonergic psychedelics act as non-selective agonists of serotonin receptors, including of the serotonin 5-HT2 receptors, but often also of other serotonin receptors, such as the serotonin 5-HT1 receptors. They are thought to mediate their hallucinogenic effects specifically by activation of serotonin 5-HT2A receptors. Psychedelics (including tryptamines like psilocin, DMT, and 5-MeO-DMT; phenethylamines like mescaline, DOM, and 2C-B; and ergolines and lysergamides like LSD) all act as agonists of the serotonin 5-HT2A receptors. Some psychedelics, such as phenethylamines like DOM and 2C-B, show high selectivity for the serotonin 5-HT2 receptors over other serotonin receptors. There is a very strong correlation between 5-HT2A receptor affinity and human hallucinogenic potency. In addition, the intensity of hallucinogenic effects in humans is directly correlated with the level of serotonin 5-HT2A receptor occupancy as measured with positron emission tomography (PET) imaging. Serotonin 5-HT2A receptor blockade with drugs like the semi-selective ketanserin and the non-selective risperidone can abolish the hallucinogenic effects of psychedelics in humans. However, studies with more selective serotonin 5-HT2A receptor antagonists, like pimavanserin, are still needed.
== Processing == The encapsulation method depends on the requirements for any given drug or substance. These processes depend on the physiochemical properties of the core material, the wall material, and the required size. The most common ways to produce nanocapsules are nanoprecipitation, emulsion-diffusion, and solvent-evaporation. In the nanoprecipitation method, also termed solvent displacement method, nanocapsules are formed by creating a colloidal suspension between two separate phases. The organic phase consists of a solution and a mixture of organic solvents. The aqueous phase consists of a mixture of non-solvents that forms a surface film. The organic phase is slowly injected in the aqueous phase which then is agitated to form the colloidal suspension. Once the colloidal suspension is formed it will be agitated until nanocapsules begin to form. The size and shape of the nanocapsule depend on the rate of injection along with the rate of agitation. Another common way to prepare nanocapsules is the emulsion diffusion method. This method consists of three phases: organic, aqueous, and dilution phase. In this method the organic phase is added to the aqueous phase under conditions of high agitation which form an emulsion. During this process water is added to the emulsion which causes the solvent to diffuse. The result of this emulsion-diffusion is nanocapsule formation. Solvent evaporation is another effective method to prepare nanocapsules. In this process, single or double emulsions are formed from solvents and are used to formulate a nanoparticle suspension.
=== Environmental factors === Hyperglycemia is lower in higher income groups since there is access to better education, healthcare, and resources. Low-middle income groups are more likely to develop hyperglycemia, due in part to a limited access to education and a reduced availability of healthy food options. Living in warmer climates can reduce hyperglycemia due to increased physical activity while people are less active in colder climates.
Tertiary structure — domains The tertiary structure is formed by two domains known as the large and the small, which are separated by a cleft centred around the location of the bond with ATP-ADP+Pi. Below this there is a deeper notch called a "groove". In the native state, despite their names, both have a comparable depth. The normal convention in topological studies means that a protein is shown with the biggest domain on the left-hand side and the smallest domain on the right-hand side. In this position the smaller domain is in turn divided into two: subdomain I (lower position, residues 1–32, 70–144, and 338–374) and subdomain II (upper position, residues 33–69). The larger domain is also divided in two: subdomain III (lower, residues 145–180 and 270–337) and subdomain IV (higher, residues 181–269). The exposed areas of subdomains I and III are referred to as the "barbed" ends, while the exposed areas of domains II and IV are termed the "pointed" ends. This nomenclature refers to the fact that, due to the small mass of subdomain II actin is polar; the importance of this will be discussed below in the discussion on assembly dynamics. Some authors call the subdomains Ia, Ib, IIa, and IIb, respectively.
=== Origin of antiviral resistance === The genetic makeup of viruses is constantly changing, which can cause a virus to become resistant to currently available treatments. Viruses can become resistant through spontaneous or intermittent mechanisms throughout the course of an antiviral treatment. Immunocompromised patients, more often than immunocompetent patients, hospitalized with pneumonia are at the highest risk of developing oseltamivir resistance during treatment. Subsequent to exposure to someone else with the flu, those who received oseltamivir for "post-exposure prophylaxis" are also at higher risk of resistance. The mechanisms for antiviral resistance development depend on the type of virus in question. RNA viruses have high error rates during genome replication because RNA polymerases lack proofreading activity. RNA viruses also have small genome sizes that are typically less than 30 kb, which allow them to sustain a high frequency of mutations. The likelihood of mutations is exacerbated by the speed with which viruses reproduce, which provides more opportunities for mutations to occur in successive replications. Billions of viruses are produced every day during the course of an infection, with each replication giving another chance for mutations that encode for resistance to occur. Multiple strains of one virus can be present in the body at one time, and some of these strains may contain mutations that cause antiviral resistance.
Sources: en.wikipedia.org
The main proposal is modulation of neurotrophic factors such as brain-derived neurotrophic factor, supported largely by animal experiments. Receptor-level targets have not been firmly established. Most reviews describe the mechanism as only partially characterized.
The compound is registered as a medicine in Russia, so clinical work has concentrated there. Trials elsewhere are few and generally small. This geographic concentration is a recognized limitation in evidence reviews.
Some fraction may reach the central nervous system through olfactory pathways, and this is often cited as the rationale for the nasal route. The size of that fraction in humans is not well quantified. Blood concentrations after nasal dosing are low, which complicates measurement.
It is a short synthetic peptide built from seven amino acids: methionine, glutamic acid, histidine, phenylalanine and three prolines. The sequence derives from the 4-10 fragment of adrenocorticotropic hormone with an added proline-glycine-proline tail. No plant or animal extract is involved; the material is produced by solid-phase peptide synthesis.