Everything below concerns reversed-phase HPLC. We keep the language plain, cite what the science says, and separate well-supported claims from open questions.
Updated 2026-08-01. Numbers and descriptions here follow the published literature rather than marketing material.
Once dissolved, the peptide is considerably less stable than the solid. Aqueous solutions are usually prepared at neutral to slightly acidic pH, filtered, and divided into single-use aliquots before freezing. Repeated freeze-thaw cycles are a common cause of avoidable loss and are best prevented by never refreezing a thawed aliquot. Adsorption to plastic and glass surfaces can lower the measured concentration of dilute solutions, particularly below roughly 0.1 mg/mL. Buffer choice, salt content, and container material all influence how much peptide remains detectable after storage.
Identity and purity are established with standard peptide methods. Reversed-phase HPLC with ultraviolet detection near 214 nm resolves the parent peak from deletion and truncation byproducts, and reports typically quote a main-peak percentage. Mass spectrometry by electrospray or MALDI-TOF confirms the expected molecular mass, while amino acid analysis or peptide mapping can verify composition when the sequence itself is in question. A certificate of analysis that pairs a chromatogram with a mass spectrum is more informative than a purity figure alone. Counter-ion content and residual solvents are separate specifications and are frequently omitted.
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.
| Property | Value | Notes |
|---|---|---|
| Solid storage temperature | -20 °C or below | Desiccated and protected from light |
| Solution storage temperature | -80 °C as single-use aliquots | Avoid repeated freeze-thaw cycles |
| Purity assessment method | RP-HPLC, around 214 nm | Reported as main-peak area percent |
| Identity confirmation method | ESI-MS or MALDI-TOF | Measured mass compared with calculated mass |
| Common synonyms | ACTH(4-10) analog; Met-Glu-His-Phe-Pro-Gly-Pro | Also written as Semaxum in some sources |
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.
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。
Semax 是一种人工合成的七肽，氨基酸序列为 Met-Glu-His-Phe-Pro-Gly-Pro，单字母缩写记作 MEHFPGP。它被归类为促肾上腺皮质激素片段 ACTH(4-10) 的结构类似物，但并不天然存在于生物体内。母体片段 ACTH(4-10) 的序列为 Met-Glu-His-Phe-Arg-Trp-Gly，Semax 替换了中间两个残基，并在羧基端延长了 Pro-Gly-Pro 三肽。这种延长被普遍认为能提升分子对肽酶的耐受性。
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。
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.
Dissolution is normally performed in water, phosphate-buffered saline, or normal saline, since the peptide is freely soluble in aqueous media and is rarely handled with strong organic solvents. Solution pH should be kept near neutral, because extreme acidity or alkalinity accelerates backbone hydrolysis and encourages oxidation of the methionine side chain. Once dissolved, the material is less stable than the dry powder and is commonly divided into single-use portions and frozen. Buffers containing primary amines, such as Tris, are often avoided because of possible side reactions.
(1887), banker, prominent figure in Thoroughbred horse racing Richard Stevens (1890), attorney and real estate developer in Hoboken, New Jersey, grandson of inventor John Stevens and son of Stevens Institute of Technology founder Edwin Augustus Stevens Cortlandt F. Bishop (1891), aviator and book collector, grandson of philanthropist Benjamin Hazard Field Howard Gould* (1894), financier, son of railroad tycoon Jay Gould Joseph Peter Grace Sr. (1894), businessman, polo player, heir to W. R. Grace and Company; founder of Pan American-Grace Airways and Grace National Bank Samuel Bloomingdale (1895), businessman, heir to the Bloomingdale's department store fortune Dexter M. Ferry Jr. (1898), director of D.M. Ferry & Co.; member of the Michigan House of Representatives Charles A. Dana (1902), philanthropist who founded the Dana Foundation and Dana Holding Corporation John Knowles Fitch (1902), founder of Fitch Ratings, one of the Big Three rating agencies Marcellus Hartley Dodge Sr. (1903), chairman of the Remington Arms Company, husband of Geraldine Rockefeller Dodge George Earle Warren (1903), vice president of Chase Manhattan Bank Pendleton Dudley (1906), public relations executive, founder of Dudley-Anderson-Yutzy William Gage Brady Jr.
== Uses == Some of the advantages resulting from adopting LOINC may include improved communication in integrated healthcare delivery networks, improved community wide electronic health records, the automatic transfer to public health authorities of case reports for reportable diseases (e.g. for disease control or detection of epidemics), improved transfer of payment information for services rendered and a significant improvement in the overall quality of health care by reducing errors in the system. The fact that universal standards are being promoted (if not adopted by national organizations and agencies) is an indication that the dialogue will continue regarding the development, structure, financing, monitoring, enforcement, and integration of standards within the broader health care system. International interest in LOINC continues to grow. A number of efforts have been undertaken to translate the LOINC documents and terms into various languages, such as Simplified Chinese, German, Spanish. As of January, 2009, the software RELMA (Regenstrief LOINC Mapping Assistant) is available in separate downloads that contain an additional word index in Spanish, Simplified Chinese, or Korean, which allows searching in these languages in addition to English. Harmonization efforts between LOINC and SNOMED CT were initiated in 2012.
=== Employing biology === Many research programs are also focused on employing natural biomolecules to perform biological tasks or to support a new chemical method. In this regard, chemical biology researchers have shown that DNA can serve as a template for synthetic chemistry, self-assembling proteins can serve as a structural scaffold for new materials, and RNA can be evolved in vitro to produce new catalytic function. Additionally, heterobifunctional (two-sided) synthetic small molecules such as dimerizers or PROTACs bring two proteins together inside cells, which can synthetically induce important new biological functions such as targeted protein degradation.
Sources: en.wikipedia.org
Sometimes I do not understand them their Inca language, I don't know if they are calm or not!""We no longer have to count on the Chileans and Argentines, and these Peruvians are the most miserable men for war. Of course, we must resolve to sustain this fight alone." Hiram Paulding, a US sailor who visited him in his camp in Huaraz, recounts that Bolívar told him that the Peruvians "were cowards and that, as a people, they did not have a single manly virtue. In short, his insults were harsh and unreserved... Then they told me that he always used to speak like that about Peruvians." According to Jorge Basadre, Bolívar's anti-Peruvian feelings would explain his triumphalist proclamations with Colombia, where he declared, after the Battle of Ayacucho, that "The loyalty, perseverance and courage of the Colombian army has done everything". Given this, it has been denounced that Bolívar had a very unpleasant treatment with the Peruvian troops under his command, an example is in a case that occurred with Ramon Castilla, who for trying to prevent a Peruvian cavalry corps from being arbitrarily added to a Gran Colombian unit during the Junín campaign, the young Peruvian soldier would suffer a humiliating insult: the Venezuelans (under the command of Bolívar) would have him put in stocks, and even wanted to shoot him, despite being part of the same side and in combat against the royalists. In the process a duel took place between the Cuiraceros of Peru and the Hussars of Colombia that took place on December 26, 1823.
==== Brown ==== Human feces ordinarily has a light to dark brown coloration, which results from a combination of bile, and bilirubin derivatives of stercobilin and urobilin, from dead red blood cells. Normally it is semisolid, with a mucus coating.
Dextrorphan (DXO) is a psychoactive drug of the morphinan class which acts as an antitussive or cough suppressant and in high doses a dissociative hallucinogen. It is the dextrorotatory enantiomer of racemorphan; the levorotatory enantiomer is levorphanol. Dextrorphan is produced by O-demethylation of dextromethorphan by CYP2D6. Dextrorphan is an NMDA antagonist and contributes to the psychoactive effects of dextromethorphan.
Keeping the temperatures sufficiently low is accomplished with specially designed containers and dry ice, but dry ice is only allowed in limited quantities on airplanes as the gases released via sublimation may be toxic. In the United States, the Federal Aviation Administration (FAA) limits the amount of dry ice on a Boeing 777-224 to 3,000 lb (1,400 kg), but it temporarily allowed United Airlines to transport up to 15,000 lb (6,800 kg)—nearly 1 million doses—between Brussels and Chicago. The Centers for Disease Control and Prevention (CDC) tasked McKesson Corporation with vaccine distribution in the U.S.; the company handled all major vaccines except Pfizer's. American Airlines, Boeing, and Delta Air Lines are also working to increase dry ice transportation capacity, and American, Delta, and United each operate their own cold storage networks in the US. FedEx and UPS have installed ultra-cold freezers at air cargo hubs in Europe and North America, and UPS can manufacture 1,200 lb (540 kg) of dry ice per hour.
Sources: en.wikipedia.org
Each freeze-thaw cycle can degrade a fraction of the peptide and promote aggregation. Dividing a stock solution into single-use volumes removes repeated cycling as a variable. It also limits the time a thawed solution spends at room temperature.
A high main-peak percentage says little about identity, counter-ion content, or residual solvents. It also does not distinguish an isomer or a closely eluting analog. Mass confirmation and the accompanying documentation cover those gaps.
Salt form changes mass, solubility, and hygroscopicity, and acetate and trifluoroacetate salts behave differently in solution. Storage guidance still centers on -20 °C for powder and lower temperatures for solutions. The certificate should state which salt is present.
It is a synthetic peptide of seven amino acids. Its backbone corresponds to a fragment of adrenocorticotropic hormone extended at the carboxyl end. The material is distributed as a lyophilized solid for laboratory use.