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.
Updated 2025-12-10. Numbers and descriptions here follow the published literature rather than marketing material.
Purity assessment relies mainly on reversed-phase high-performance liquid chromatography, which separates the target heptapeptide from truncated sequences, deletion analogues, and oxidised forms. Mass spectrometry, usually coupled to liquid chromatography, confirms identity through the expected molecular ion and reveals modifications such as methionine sulfoxide formation. Amino acid analysis can verify composition, and tandem mass spectrometry supports sequence confirmation. Ultraviolet detection near 254 to 280 nanometres is convenient because the phenylalanine and histidine residues absorb in that region. Nuclear magnetic resonance is rarely used for routine release testing.
Common degradation pathways include oxidation of the methionine side chain, hydrolysis of the peptide backbone, and aggregation under unfavourable pH or concentration. Stability studies typically monitor the main peak by chromatography and report total related substances as a percentage. Because no official monograph exists, acceptance criteria vary between laboratories, and reported purity values are not directly comparable across suppliers. Analysts therefore document the method, column, and detection wavelength alongside each result, and open questions remain about how much biological activity the oxidised forms retain.
Solid semax is typically supplied as a lyophilised powder that is hygroscopic and sensitive to moisture, light, and repeated temperature cycling. Long-term storage of the dry peptide is generally recommended at approximately -20 degrees Celsius, while shorter working periods may use refrigeration at 2 to 8 degrees Celsius. Vials should remain tightly closed and desiccated when brought to room temperature, because condensation can damage the material before it is weighed. Dividing a batch into aliquots is preferable to thawing one container repeatedly.
该化合物于二十世纪八十年代在俄罗斯被开发，相关工作由俄罗斯科学院分子遗传学研究所的研究团队主导。开发目标并非复制 ACTH 的完整激素活性，而是寻找保留其神经作用方向、同时去除促肾上腺皮质激素释放效应的短肽片段。研究记录显示，这一方向促成了多个相关短肽的合成与筛选，而 Semax 是其中被研究最广泛的一个。当地文献常以 Семакс 这一名称指代它。
研究兴趣主要集中在神经营养因子相关的路径上，包括脑源性神经营养因子与神经生长因子的表达变化。部分实验报告称在特定条件下观察到这些因子的水平上升，但具体信号通路和剂量依赖关系仍未完全厘清。多数公开数据来自细胞模型和动物实验，人体对照研究数量有限。因此，该化合物的作用机制在文献中属于活跃讨论，而非已经确立的定论。
| Property | Value | Notes |
|---|---|---|
| Typical analytical method | Reversed-phase HPLC with UV detection | Separates target peptide from truncated and oxidised forms |
| Identity confirmation | LC-MS or ESI-MS | Compares observed and calculated molecular ion |
| Primary degradation route | Methionine oxidation | Forms the sulfoxide; monitored as an early-eluting peak |
| Short-term storage | 2 to 8 degrees Celsius | Applies to working vials and reconstituted portions |
| Common synonyms | ACTH(4–10) analogue, MEHFPGP | Descriptive names used in laboratory catalogues |
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.
Semax is a synthetic heptapeptide whose sequence is Met-Glu-His-Phe-Pro-Gly-Pro. The first four residues correspond to the ACTH(4-10) fragment, while the terminal Pro-Gly-Pro extension was added to improve metabolic stability. Its molecular formula is C37H51N9O10S and its monoisotopic mass is approximately 813.9 Da. The compound is classified as a peptide research chemical and as a registered pharmaceutical product in Russia, but it does not hold marketing approval in the European Union or the United States. Naming conventions vary across supplier catalogs.
Development of the compound took place in the Soviet Union during the 1980s, largely through peptide research groups affiliated with the Shemyakin-Ovchinnikov Institute and Moscow State University. Investigators screened fragments of adrenocorticotropic hormone for activity on the central nervous system while attempting to separate cognitive effects from hormonal ones. The shortened sequence was selected because it retained behavioral activity in animal models without stimulating corticosteroid release. Early publications described the molecule as an ACTH(4-10) analog.
Published research on this peptide originates mainly from Russian laboratories, and the wider international literature is comparatively thin. Studies have used rodent models of stroke, hypoxia, and memory tasks, with a smaller number of human trials reported. Reported outcomes include changes in attention and memory measures, along with effects on neurotrophic factor expression in some experiments. Small sample sizes, inconsistent dosing protocols, and limited independent replication are widely noted limitations, so the strength of the clinical evidence remains an open question.
DHX8 has multiple molecular functions like ATP-binding by, selective and non-covalent interactions with the coenzyme and enzyme regulator adenosine 5' triphosphate. Also identical protein binding (creates a similar type of interactions as described above but with other proteins), RNA binding and RNA helicase activity, based on catalysis of the reaction that unwinds an RNA helix: ATP + H2O = ADP + phosphate
D* → D + hν For example, A could be luminol and B could be hydrogen peroxide. D would be 3-aminophthalate (3-APA). In theory, one photon of light should be given off for each molecule of reactant. In practice, the yield ("quantum efficiency") is often low owing to side reactions. Chemiluminescence differs from fluorescence or phosphorescence in that the electronic excited state is the product of a chemical reaction rather than of the absorption of a photon. It is the antithesis of a photochemical reaction, in which light is used to drive an endothermic chemical reaction. Instead, here light is generated from a chemically exothermic reaction. The chemiluminescence might be also induced by an electrochemical stimulus and in that case, it is called electrochemiluminescence.
The reaction proceeds according to the usual serine protease mechanism. First, His-57 deprotonates Ser-195, allowing it to serve as a nucleophile. Deprotonated Ser-195 then reacts with the carbonyl carbon of a peptide, forming a tetrahedral intermediate. The tetrahedral intermediate then collapses, resulting in an H2N-R1 leaving group, which is protonated through His-57. Finally, His-57 deprotonates a water molecule, which can then serve as a nucleophile by similarly reacting with the carbonyl carbon. Collapse of the tetrahedral intermediate then results in a Ser-195 leaving group, which is protonated through His-57, resulting in all residues returned to their pre-catalytic state, and a carboxylic acid where there was previously a peptide bond.
== New Directions Act == In the late 1960s, foreign aid became one of the focal points in Legislative-Executive differences over the Vietnam War. In September 1970, President Nixon proposed abolishing USAID and replacing it with three new institutions: one for development loans, one for technical assistance and research, and one for trade, investment and financial policy. USAID's field missions would have been eliminated in the new institutional setup. Consistent with this approach, in early 1971 President Nixon transferred the administration of private investment programs from USAID to the Overseas Private Investment Corporation (OPIC), which had been established by foreign aid legislation at the end of 1969. Congress did not act on the President's proposal for replacing USAID but rather amended the Foreign Assistance Act to direct that USAID emphasize "Basic Human Needs": food and nutrition; population planning and health; and education and human resources development. Specifically, USAID's budget would be reformed to account for expenditures for each of these Basic Human Needs, a system referred to as "functional accounts". (Previously, budgets had been divided between categories such as "development loans, technical assistance, Alliance for Progress [for Latin America], loans and grants, and population.") The new system was based on a proposal developed by a bipartisan group of House members and staff working with USAID management and outside advisors. President Nixon signed the New Directions Act into law (PL 93-189) in December 1973.
Sources: en.wikipedia.org
=== Federal funding === Canada's National Research Council (NRC) provided Providence Therapeutics with CAD$5 million for the launch of January 2021 first phase of PTX-COVID19-B clinical trials. As part of the federal government's "next generation manufacturing supercluster" program, Providence and Northern mRNA had also been "cleared to access up to $5 million" towards the manufacturing start up process, according to a federal government spokesperson. The CBC report in late April 2021 also stated that "it could be eligible for a slice of $113 million in additional funding from the National Research Council of Canada Industrial Research Assistance Program". The federal government had provided funding to some other companies in Canada that were also working to develop a COVID-19 vaccine. Sorenson as Providence Therapeutics CEO posted an open letter to Prime Minister Justin Trudeau, in which he requested $CDN 150 million upfront to be used to pay for clinical trial and material costs. On April 29, 2021, Sorenson appeared before the House of Commons standing committee on international trade, to ask the Minister of Procurement, Anita Anand, to consider PTX-COVID19-B as an alternative to Moderna and Pfizer for the "2022 booster vaccines". Sorenson said that the NRC had approached Providence Therapeutics in 2020 after the company had announced their Phase I trial PTX-COVID19-B. Sorenson told the Standing Committee that, "We've had really good dialogue ever since phase I started. That process has gone on.
=== North American supply === As the war intensified with German air raids on the UK, Florey and Ethel decided to send their children away to a safer country in July 1940. The United States was not yet at war, and John Fulton, the Sterling Professor of Physiology at Yale University, and his wife Lucia agreed to care for them at their home in New Haven, Connecticut, "for the duration". In April 1941, the Rockefeller Foundation's Warren Weaver met with Florey, and they discussed the difficulty of producing sufficient penicillin to conduct clinical trials. Weaver arranged for the foundation to fund a three-month visit to the United States for Florey and a colleague so they could explore the possibility of the production of penicillin there. Since his aim was to persuade a firm to manufacture penicillin, and Heatley knew the most about penicillin production, Florey chose to take Heatley with him, and did not tell Chain until the morning of their departure. Chain, who saw penicillin as a joint project between himself and Florey, with Heatley as a laboratory technician, was greatly offended. Chain later wrote: "I left the room silently but shattered by the experience of this underhand trick and act of bad faith, the worst so far in my experience of Florey. It spoiled my initially good relations with this man for ever." Florey and Heatley left by air from Lisbon for the United States on 27 June 1941. In New Haven Florey met Fulton and was reunited with his children.
Topical analgesia is generally recommended to avoid systemic side-effects. Painful joints, for example, may be treated with an ibuprofen- or diclofenac-containing gel (The labeling for topical diclofenac has been updated to warn about drug-induced hepatotoxicity.); capsaicin also is used topically. Lidocaine, an anesthetic, and steroids may be injected into joints for longer-term pain relief. Lidocaine is also used for painful mouth sores and to numb areas for dental work and minor medical procedures. In February 2007 the FDA notified consumers and healthcare professionals of the potential hazards of topical anesthetics entering the bloodstream when applied in large doses to the skin without medical supervision. These topical anesthetics contain anesthetic drugs such as lidocaine, tetracaine, benzocaine, and prilocaine in a cream, ointment, or gel.
Sources: en.wikipedia.org
The UNESCO International Bioethics Committee recommended a precautionary global moratorium on the creation of mirror-image organisms, and the UK Government Office for Science held an expert roundtable that recommended "prevent[ing] the development of replicating mirror organisms." Several philanthropic funders have also stated that they will not fund research with the goal of creating mirror-image organisms, including Renaissance Philanthropy. In 2026, the UN Scientific Advisory Board called for "proactive multilateral action, such as a dedicated global forum, to define clear 'red lines', strengthen safety and monitoring practices, and establish responsible policy well before mirror life becomes feasible", and Chinese and US policy research organizations issued a joint statement calling for "national and international frameworks to guard against the risks posed by mirror life, reaffirming the shared view that such organisms should never be created." Some scientists and scholars have argued that concerns about mirror-image life are theoretical and/or that bans on research and funding bans are premature. Others have argued that the immune system might be able to recognize mirror versions of a certain type of biomolecule. Some scientists have proposed developing guidelines for synthetic biological entities regardless of their chirality.
Another necessary and sufficient condition is that a convex quadrilateral ABCD is tangential if and only if the incircles in the two triangles ABC and ADC are tangent to each other. A characterization regarding the angles formed by diagonal BD and the four sides of a quadrilateral ABCD is due to Iosifescu. He proved in 1954 that a convex quadrilateral has an incircle if and only if
Spy&Go purification of proteins with either N-terminal, internal or C-terminal SpyTag have all been reported. SpyDock resin is compatible with all SpyTag generations (SpyTag, SpyTag002, SpyTag003) and it does not interfere with the later covalent conjugation of the purified proteins with SpyCatcher.
Sources: en.wikipedia.org
Dry powder is usually kept at about -20 degrees Celsius for long-term storage and at 2 to 8 degrees Celsius for short working periods. Containers should stay sealed and protected from light and moisture to limit degradation.
Oxidation of the methionine residue to the sulfoxide is a frequently reported change, and it usually appears as an earlier-eluting peak in reversed-phase chromatography. Backbone hydrolysis products can also accumulate in aqueous solution.
Liquid chromatography coupled with mass spectrometry is the usual approach, because the observed molecular ion can be compared with a calculated mass of about 813.9 Da. Retention time alone does not establish identity.
不是。Semax 是完全人工合成的七肽，自然界中没有对应的已知肽段。它的设计灵感来自促肾上腺皮质激素片段 ACTH(4-10)，但序列经过了替换和延长。