A practical reference on intranasal delivery: what it is, how it behaves, what the literature reports, and where the honest uncertainties sit.
This page was last updated on 2026-01-18 and is reviewed periodically as new material appears.
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.
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.
Clinical reports describe use in ischaemic stroke, transient ischaemic attack, optic nerve conditions, and cognitive complaints, but most of these studies are small and were conducted in a single region. Systematic reviews have generally described the evidence base as limited in size and variable in methodological quality. Randomised controlled data suitable for international regulatory assessment are scarce. As a result, major treatment guidelines outside Russia do not include the peptide, and interest in it remains largely research-driven rather than routine clinical.
Semax is a synthetic heptapeptide with the sequence Met-Glu-His-Phe-Pro-Gly-Pro. It is described in the literature as an analogue of the ACTH(4–10) fragment, a short N-terminal portion of adrenocorticotropic hormone that retains some neurotropic activity without the full hormonal effects of the parent peptide. The molecule carries a methionine residue at the N-terminus and two proline residues near the C-terminus, features that shape both its interactions with receptor systems and its chemical stability. The free peptide corresponds to the formula C37H51N9O10S and a molecular mass near 813.9 Da.
| 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 |
纯度评估以反相高效液相色谱为主，通过主峰面积百分比给出粗略结果，再配合电喷雾质谱核对分子量。氨基酸分析可验证组成比例，手性色谱或毛细管电泳用于检查残基构型。常见杂质包括缺失序列的短肽、氧化产物与二聚体。由于多数市售品不附带完整检验报告，独立第三方检测常被用来核实标称值。
从分子层面看，Semax 是线性七肽，没有二硫键、糖基或脂链修饰，N 端为游离氨基，C 端为游离羧基。分子含组氨酸与谷氨酸侧链，因此在水和甲醇等极性溶剂中溶解良好，在非极性溶剂中溶解有限。计算分子量约为 814 Da，与其质子化离子的质荷比吻合，可用于质谱确认。
稳定性主要由水解与氧化两条路径支配。肽键在中性或弱酸性条件下相对稳定，遇到强碱或长时间高温则明显断裂；甲硫氨酸侧链容易被氧化成亚砜，使主峰前移并拉低实际含量。金属离子、光照和反复冻融会进一步促进降解或聚集。冻干粉在低温避光条件下可存放较长时间，配制后的水溶液通常需要冷藏并尽快用完。
Regulatory status varies sharply by country. Semax is registered for medical use in Russia, where it appears in formularies as a nasal solution, and it also holds registration in a small number of neighbouring states. It has no approval from the United States Food and Drug Administration or the European Medicines Agency, and it is not a scheduled controlled substance in most jurisdictions. Elsewhere it circulates mainly as laboratory material, so purity documentation comes from suppliers rather than from a national pharmacopoeia.
Semax is a synthetic peptide created in the Soviet Union during the early 1980s by researchers working in Moscow. It was built from the short adrenocorticotropic hormone fragment known as ACTH(4-10), and the chain was then extended with three additional amino acids. The resulting molecule was named semax and entered clinical use in Russia in 1994. It is generally described as a nootropic and neuroprotective agent rather than as a hormone analogue.
The parent fragment ACTH(4-10) carries the sequence Met-Glu-His-Phe-Arg-Trp-Gly. Semax replaces the arginine and tryptophan positions with a proline-glycine-proline tail, giving Met-Glu-His-Phe-Pro-Gly-Pro. That change removes residues associated with adrenal stimulation, so the peptide does not drive cortisol release the way full ACTH does. This distinction shapes how the compound is grouped in the literature, where it sits with neuropeptides and peptide neuromodulators rather than with corticosteroids.
Hair analysis to detect addictive substances has been used by court systems in the United States, United Kingdom, Canada, and other countries worldwide. In the United States, hair testing has been accepted in court cases as forensic evidence following the Frye Rule, the Federal Rules of Evidence, and the Daubert Rule. As such, hair testing results are legally and scientifically recognized as admissible evidence. Hair testing is commonly used in the USA as pre-employment drug test. The detection time for this test is roughly 3 months, which is the time, that takes head hair to grow ca. 1.5 inches, that are collected as a specimen. Longer detection times are possible with longer hair samples. A 2014 collaborative US study of 359 adults with moderate-risk drug use found, that a large number of participants, who reported drug use in the last 3 months, had negative hair tests. The tests were done using an immunoassay followed by a confirmatory GC-MS. For marijuana, only about half of self-disclosed users had a positive hair test. Under-identification of drug use by hair testing (or over-reporting) was also widespread for cocaine, amphetamines, and opioids. Because such under-identification was more common among participants, who self-reported an infrequent use, the authors suggested, that the immunoassay did not have the sensitivity required for such infrequent uses. It is worth noting, that most earlier studies reported, that hair tests found ca. 50-fold higher prevalence of illicit drug use, than self reports.
The drug works in hypertensive patients with high, normal, or low renin plasma concentrations, although acebutolol may be more efficient in patients with high or normal renin plasma concentrations. In clinically relevant concentrations, a membrane-stabilizing effect does not appear to play an important role.
The domain of automotive design has been traditionally characterized as male-dominated. As a result, there has been a lack of female automotive designers in the area of automotive safety compared to male automotive designers. This leads to oversights in automotive safety and ergonomics for female consumers, who make up 62% of all new cars sold in the USA. According to the Insurance Institute for Highway Safety (IIHS), women are less likely to get into a crash than men are. However, women are 17% more likely to die in a car crash and 73% more likely to sustain serious injuries from a crash when compared to men. In rear-end collisions, female drivers face a higher risk of whiplash injuries when compared to their male counterparts due to their lighter weight which causes them to be propelled forward more rapidly. To mitigate these problems, Consumer Reports states that regulators have called for a female crash dummy to be implemented in crash testing since 1980. When pregnant, women should continue to use seatbelts and airbags properly. A University of Michigan study found that "unrestrained or improperly restrained pregnant women are 5.7 times more likely to have an adverse fetal outcome than properly restrained pregnant women". If seatbelts are not long enough, extensions are available from the car manufacturer or an aftermarket supplier.
On March 22, 2023, Valve announced Counter-Strike 2, which utilizes the Source 2 game engine. It was originally announced as a free upgrade to Global Offensive with a summer 2023 release date. On September 1, 2023, it was released as a limited beta, and the game replaced Global Offensive on September 27.
Anode-free battery Blade battery Borate oxalate Comparison of commercial battery types European Battery Alliance Flow battery Nanowire battery Sodium-ion battery Thin-film lithium-ion battery VRLA battery Ultium
Sources: en.wikipedia.org
==== Reverse incremental ==== A Reverse incremental backup method stores a recent archive file "mirror" of the source data and a series of differences between the "mirror" in its current state and its previous states. A reverse incremental backup method starts with a non-image full backup. After the full backup is performed, the system periodically synchronizes the full backup with the live copy, while storing the data necessary to reconstruct older versions. This can either be done using hard links—as Apple Time Machine does, or using binary diffs.
1-Pyrroline-5-carboxylic acid (systematic name 3,4-dihydro-2H-pyrrole-2-carboxylic acid) is a cyclic imino acid. Its conjugate base and anion is 1-pyrroline-5-carboxylate (P5C). In solution, P5C is in spontaneous equilibrium with glutamate-5-semialdehyde (GSA).
== Clinical significance == EF-G in pathogenic bacteria can be inhibited by antibiotics that prevent EF-G from binding to the ribosome, carrying out translocation or dissociating from the ribosome. For example, the antibiotic thiostrepton prevents EF-G from binding stably to the ribosome, while the antibiotics dityromycin and GE82832 inhibit the activity of EF-G by preventing the translocation of the A site tRNA. Dityromycin and GE82832 do not affect the binding of EF-G to the ribosome, however. The antibiotic fusidic acid is known to inhibit Staphylococcus aureus and other bacteria by binding to EF-G after one translocation event on the ribosome, preventing EF-G from dissociating. However, some bacterial strains have developed resistance to fusidic acid due to point mutations in the fusA gene, which prevents fusidic acid from binding to EF-G.
== Pharmacology == The drug potentiates the tropomyosin receptor kinases TrkA, TrkB, and TrkC with EC50Tooltip half-maximal effective concentration values of 382 nM, 295 nM, and ~330 nM, respectively. As a positive allosteric modulator of TrkA and TrkB, ACD856 potentiates the effects of brain-derived neurotrophic factor (BDNF) and nerve growth factor (NGF). In addition to the tropomyosin receptor kinases, ACD856 is also a similarly potent positive allosteric modulator of certain other receptor tyrosine kinases, including the insulin-like growth factor 1 receptor (IGF1R) and the fibroblast growth factor receptor 1 (FGFR1). However, its efficacies at the IGF1R and FGFR1 were much lower than at the TrkA, TrkB, and TrkC. In animals, ACD856 has been found to reverse scopolamine- and dizocilpine (MK-801)-induced memory impairment, to improve age-related memory deficits, and to have sustained antidepressant-like activity. It has also been reported to possess neuroprotective properties. In humans, the drug has been shown to cross the blood–brain barrier and to induce dose-dependent changes in electroencephalogram parameters. No significant tolerability or safety concerns have been identified in preclinical research or phase 1 clinical trials. The drug's clinical pharmacokinetics have been characterized and its elimination half-life is approximately 19 hours.
Native gels are run in non-denaturing conditions so that the analyte's natural structure is maintained. This allows the physical size of the folded or assembled complex to affect the mobility, allowing for analysis of all four levels of the biomolecular structure. For biological samples, detergents are used only to the extent that they are necessary to lyse lipid membranes in the cell. Complexes remain — for the most part — associated and folded as they would be in the cell. One downside, however, is that complexes may not separate cleanly or predictably, as it is difficult to predict how the molecule's shape and size will affect its mobility. These effects have been successfully addressed by preparative native PAGE. Unlike denaturing methods, native gel electrophoresis does not use a charged denaturing agent. The molecules being separated (usually proteins, peptides, or nucleic acids), therefore differ not only in molecular mass and intrinsic charge, but also the cross-sectional area, and thus, experience different electrophoretic forces dependent on the shape of the overall structure. For proteins, since they remain in the native state, they may be visualized not only by general protein staining reagents but also by specific enzyme-linked staining. A specific experiment example of an application of native gel electrophoresis is to check for enzymatic activity to verify the presence of the enzyme in the sample during protein purification.
Sources: en.wikipedia.org
==== Tissue engineering ==== For some polymers it was demonstrated that thermoresponsive behavior can be transferred to surfaces. The surface is either coated with a polymer film or the polymer chains are bound covalently to the surface. This provides a way to control the wetting properties of a surface by small temperature changes. The described behavior can be exploited in tissue engineering since the adhesion of cells is strongly dependent on the hydrophilicity/hydrophobicity. This way, it is possible to detach cells from a cell culture dish by only small changes in temperature, without the need to additionally use enzymes (see figure). Respective commercial products are already available.
There are nine subtilisin homologs in mammals; in addition to proprotein convertase 1 and 2, other members of this enzyme family include furin, PACE4, PC4, PC5/6, PC7/8, PCSK9, and SKI1/S1P. Proprotein convertase 1 converts prorenin into renin.
George Walker Bush (born July 6, 1946) is an American former politician, businessman, and Air Force veteran who served as the 43rd president of the United States from 2001 to 2009. A member of the Republican Party, he served as the 46th governor of Texas from 1995 to 2000. He is the eldest son of George H. W. Bush, the 41st president of the United States. Born into the prominent Bush family in New Haven, Connecticut, Bush flew warplanes in the Texas Air National Guard in his twenties. After graduating from Harvard Business School in 1975, he worked in the oil industry. He later co-owned the Major League Baseball team Texas Rangers before being elected governor of Texas in 1994. As governor, Bush successfully sponsored legislation for tort reform, increased education funding, set higher standards for schools, and reformed the criminal justice system. He also helped make Texas the leading producer of wind-generated electricity in the United States. In the 2000 presidential election, he defeated Democratic incumbent vice president Al Gore while losing the popular vote after a narrow and contested United States Electoral College win, which involved the Supreme Court decision Bush v. Gore to stop a recount in Florida. In his first term, Bush signed a major tax-cut program and an education-reform bill, the No Child Left Behind Act. He pushed for socially conservative efforts such as the Partial-Birth Abortion Ban Act, restrictions on same-sex marriage, and faith-based initiatives.
== History == Lethal injection gained popularity in the late 20th century as a form of execution intended to supplant electrocution, gas inhalation, hanging and firing squad, which were considered less humane. It has become the most common form of legal execution in the United States. Lethal injection was proposed on January 17, 1888, by Julius Mount Bleyer, a New York doctor who praised it as being cheaper than hanging. Bleyer's idea would not be revived until the mid-1970s, when Texas and Oklahoma adopted the modern version of the method; a series of botched executions led to an eventual rise of public disapproval of electrocutions in the 1980s. Lethal injections were first used by Nazi Germany to execute prisoners during World War II. Nazi Germany developed the Aktion T4 euthanasia program led by Karl Brandt as one method to terminate Lebensunwertes Leben ("life unworthy of life"). During the war, lethal injections were also administered to children detained at the Sisak concentration camp by the camp's commander, the physician Antun Najžer. The Royal Commission on Capital Punishment 1949–1953 considered lethal injection but eventually ruled it out after pressure from the British Medical Association (BMA).
With 21 successful stolen bases in 28 attempts, it was his first season in the 20–20 club, that is, to steal 20 bases while hitting 20 home runs in the same season. Bagwell reached base 324 total times and in all but 11 games. He led the NL in doubles with 48 while earning his second All-Star selection and finishing ninth in the MVP voting. Rumors had surfaced during the 1996 season that manager Terry Collins did not get along well with Bagwell and Biggio, largely contributing to his dismissal. The Astros hired team color commentator Larry Dierker after the season to replace him. According to his autobiography, This Ain't Brain Surgery, Dierker was asked during the interview how he would handle the players. His response: "'Look, I'm tired of this Bagwell and Biggio s---,' I said. 'Bagwell and Biggio will not be a problem, believe me.' I now believe that this statement is the one that got me the job." The Astros won division titles in four of five seasons with Dierker as manager; however, in each instance, they did not advance past the first round of the playoffs, and 2001 was Dierker's last season as the club's manager.
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 described as a synthetic analogue of the ACTH(4–10) fragment, a short segment of adrenocorticotropic hormone. Its sequence differs from that fragment and includes two proline residues, which influence stability and behaviour in solution.