This is a working overview of nasal formulation, written for readers who want more than a one-paragraph summary but less than a textbook.
Reviewed 2025-09-16. Anything still debated is marked as such rather than presented as settled.
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。
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。
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.
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.
| Property | Value | Notes |
|---|---|---|
| 分子式 | C37H51N9O10S | 游离碱形式 |
| 等电点 | 约 6.5 | 估算值，随缓冲体系变化 |
| 主要降解途径 | 水解与氧化 | 侧链氧化最为常见 |
| 溶液储存 | 2 至 8 摄氏度避光 | 避免反复冻融 |
| 常规分析手段 | 反相色谱与质谱联用 | 氨基酸分析辅助核对 |
Identity and purity of Semax are established mainly by reversed-phase high-performance liquid chromatography coupled with mass spectrometry. The chromatographic trace gives a purity estimate as a percentage of total peak area, while electrospray or matrix-assisted laser desorption ionization confirms the molecular mass against the calculated value. Amino acid analysis and sequence-specific fragmentation provide further confirmation when a supplier's chain of custody is unclear. Vendors frequently quote a purity figure without stating the detection wavelength or the integration method, which limits how far one number can be compared with another.
Stability depends heavily on physical state. Lyophilized powder held dry, cold and dark retains its content over long periods, whereas dissolved peptide begins to change within days at room temperature. The most cited degradation route is oxidation of the methionine residue, which converts the peptide to a sulfoxide form that elutes differently on chromatography. Hydrolysis of amide bonds and adsorption onto container walls contribute smaller losses. Buffers that exclude oxygen from the headspace slow the oxidation pathway, but no single condition prevents all change indefinitely.
Practical handling follows from those properties. Bulk material is best divided into single-use portions soon after receipt, because each thaw exposes the whole container to moisture and temperature cycling. Vials should be allowed to reach room temperature before opening to prevent condensation on the powder. Low-binding plasticware reduces loss of dilute solutions, and sterile filtration is used when a preparation must remain free of microbial growth. Records of batch number, reconstitution date and storage history are what allow a later analytical result to be interpreted meaningfully.
Semax is a synthetic heptapeptide with the sequence Met-Glu-His-Phe-Pro-Gly-Pro. Its chain combines the first seven residues of corticotropin with a C-terminal proline-glycine-proline extension, a modification intended to slow enzymatic breakdown. The free peptide has a molecular mass near 813.9 daltons. It belongs to the class of ACTH-derived fragments studied for central nervous system activity rather than for adrenal steroid stimulation. This structural relationship to a natural hormone fragment is the usual starting point for describing the compound in the literature.
Development took place during the 1980s at institutes of the Russian Academy of Sciences, where peptide fragments of ACTH were screened for cognitive and neuroprotective effects. The compound received regulatory approval in Russia as a nasal preparation, marketed for conditions such as ischemic stroke, transient ischemic attacks, and optic nerve disorders. Registration in other countries has not followed. Most published clinical reports originate from a small number of Russian research groups, and independent replication outside that setting remains limited. The regulatory status therefore differs sharply between Russia and the rest of the world.
Laboratory work points toward modulation of neurotrophic signaling, particularly expression of brain-derived neurotrophic factor and nerve growth factor in hippocampal tissue. Studies also describe effects on monoamine turnover, inflammatory mediators, and oxidative markers. These observations come mainly from animal models and cultured cells, so the causal chain in humans is not firmly established. Whether the reported molecular changes translate into measurable clinical benefit is an open question. Reviews generally present the mechanism as plausible rather than demonstrated.
is the second viscosity coefficient (or bulk viscosity). If a fluid does not obey this relation, it is termed a non-Newtonian fluid, of which there are several types. Non-Newtonian fluids can be either plastic, Bingham plastic, pseudoplastic, dilatant, thixotropic, rheopectic, viscoelastic. In some applications, another rough broad division among fluids is made: ideal and non-ideal fluids. An ideal fluid is non-viscous and offers no resistance whatsoever to a shearing force. An ideal fluid really does not exist, but in some calculations, the assumption is justifiable. One example of this is the flow far from solid surfaces. In many cases, the viscous effects are concentrated near the solid boundaries (such as in boundary layers) while in regions of the flow field far away from the boundaries the viscous effects can be neglected and the fluid there is treated as it were inviscid (ideal flow). When the viscosity is neglected, the term containing the viscous stress tensor
=== Actin binding === Thymosin β4 was initially perceived as a thymic hormone. However this changed when it was discovered that it forms a 1:1 complex with G (globular) actin, and is present at high concentration in a wide range of mammalian cell types. When appropriate, G-actin monomers polymerize to form F (filamentous) actin, which, together with other proteins that bind to actin, comprise cellular microfilaments. Formation by G-actin of the complex with β-thymosin (= "sequestration") opposes this. Due to its profusion in the cytosol and its ability to bind G-actin but not F-actin, thymosin β4 is regarded as the principal actin-sequestering protein in many cell types. Thymosin β4 functions like a buffer for monomeric actin as represented in the following reaction: F-actin ↔ G-actin + Thymosin β4 ↔ G-actin/Thymosin β4 Release of G-actin monomers from thymosin β4 occurs as part of the mechanism that drives actin polymerization in the normal function of the cytoskeleton in cell morphology and cell motility. The sequence LKKTET, which starts at residue 17 of the 43-aminoacid sequence of thymosin beta-4, and is strongly conserved between all β-thymosins, together with a similar sequence in WH2 domains, is frequently referred to as "the actin-binding motif" of these proteins, although modelling based on X-ray crystallography has shown that essentially the entire length of the β-thymosin sequence interacts with actin in the actin-thymosin complex.
== Prevention == Cara Myer, the author of "The Tea and Toast Syndrome: Psychosocial Aspects of Congregate Dining" suggests that congregate dining for older adults may be an excellent strategy to prevent tea and toast syndrome. Myer mentions that social service interventions for malnutrition, including congregate dining, are often under-utilized and could provide a stimulating environment that may improve the quality of life of many older adults. Further, general preventative measures focus on evaluating the nutrition of older adults, including keeping a record of weight patterns, helping with meal plans focusing on nutrient-rich foods, and using local services such as a meal delivery program. Additional strategies include:
The two substrates of this enzyme are prephenic acid and oxidised nicotinamide adenine dinucleotide phosphate (NADP+). Its products are 4-hydroxyphenylpyruvic acid, carbon dioxide, reduced NADPH, and a proton. This enzyme belongs to the family of oxidoreductases, specifically those acting on the CH-CH group of donor with NAD+ or NADP+ as acceptor. The systematic name of this enzyme class is prephenate:NADP+ oxidoreductase (decarboxylating). Other names in common use include prephenate dehydrogenase, prephenate (nicotinamide adenine dinucleotide phosphate), dehydrogenase, and prephenate dehydrogenase (NADP). This enzyme participates in phenylalanine, tyrosine and tryptophan biosynthesis.
Sources: en.wikipedia.org
In 2009, Chipotle released an app for the iPhone that allows users to find nearby Chipotle locations, place an order, and prepay with a credit card. In 2013, Chipotle released an Android app that allows users to locate nearby Chipotle locations, place an order, prepay with a credit or gift card, and access favorites and recent orders. In late 2021, the company added a non-food item to the menu—cilantro soap. According to published reports, the soap sold out the day after its release. The soap was produced after an August 2021 Instagram post of what was thought to be a mock photo of the product. It was an effort to engage fans and haters of the herb that, "plays into a larger trend of turning digital moments into real life experiences," according to Chris Brandt, Chipotle's Chief Marketing Officer. Chipotle uses green marketing and its "Food with Integrity" platform to boost its brand image.
== Plot == A homeless Ren and Stimpy are caught again and sent to the dog pound, where they are sent to their imminent death. They are saved by an unnamed rich and senile lady (Granny) on the verge of death while a priest ordains them in a gas chamber. The duo feed themselves in Granny's limousine, grateful of their survival, when the woman decides to name them "Abraham" and "Levictus" which they reluctantly allow. The duo settle at their new home. Ren decides to shake hands with a dog he believes is a fellow pet. At first, Ren assumes the dog is sleeping and attempts to wake him up, only to discover that he is dead; Granny explains that the dog is a previous pet of hers named Ezekiel who died in his sleep, so his corpse was freeze-dried in a successful attempt of taxidermy. Suddenly, the duo are condemned by the lady for being apparently possessed, despite acting normal for their kind, as they are handed off to the lady's butler Mr. Hao, a stereotypical Chinese muscular man who beats them to a pulp. The duo, who cannot walk normally after the beating, are forced to eat literal rocks advertised as dog food. Ren breaks his teeth doing so while Stimpy chokes on it; Ren's unsuccessful attempt of the Heimlich maneuver is seen as a threat by Granny, who sprays Stimpy with water and forces him to spit. She sends them to a veterinarian who further harms them. The duo sleep in the living room when Granny forcibly moves them to the yard; they find that it is a cemetery for her pets.
=== Transitioning to commercial release (2013–2014) === A new version of the Source engine had been introduced by 2013 that, in addition to new engine features, included support for OS X and Linux platforms. However, developers had to pay to gain access to the full feature set of this engine. According to Adam Engels, the project lead at the completion of Black Mesa, Valve approached their team around this time and suggested making Black Mesa a commercial release and, thus, getting a license to the Source engine. The team considered this option, and, since access to the full Source engine would help make Black Mesa the best game they could, opted to go the commercial route to be able to pay for that license, not having originally intended to profit from the game. By November 2013, the team had affirmed that they had gotten Valve's permission to sell the game. Some of the team were later invited to Valve's offices in Bellevue, Washington in 2015. At this point in 2013, the team cautioned that a final version was still some distance away, as they were still dealing with the updated Source engine, and they had not yet done much with Xen. Crowbar Collective continued to offer the free version of Black Mesa, based on the earlier Source engine, on their website. With the new Source engine, the team started to look more closely at how Valve had used Source in Half-Life 2, compared to what they had done in the original Half-Life, and developed changes for Black Mesa that reflected what they believed were Valve's design principles in Half-Life 2.
Sources: en.wikipedia.org
电喷雾或基质辅助激光解吸电离质谱是常用手段，测得的质子化离子质荷比可换算为分子量。结果与理论值落在合理误差内，才支持结构一致的判断。
甲硫氨酸侧链含硫醚，在氧气、光照或金属离子存在时容易被氧化。氧化产物极性略增，常在色谱图上表现为主峰之前的肩峰或前伸峰。
通常建议冷藏避光，并在较短时间内使用。不存在适用于所有配方的统一期限，具体取决于浓度、缓冲体系与容器材质。
Registered medical products are most often 0.1% nasal drops. Research suppliers ship lyophilized powder, usually in milligram quantities, which is dissolved before use. The active peptide is the same in both cases; presentation and excipients differ.