This is a working overview of Reversed-phase HPLC, written for readers who want more than a one-paragraph summary but less than a textbook.
This page was last updated on 2025-12-17 and is reviewed periodically as new material appears.
Quality documentation for research-grade peptide usually includes a certificate of analysis stating purity, identity, and residual counterion content. Batch-to-batch variation in purity and salt form is a recognized issue, and comparisons across suppliers require attention to the exact counterion, for example acetate versus trifluoroacetate. Sequence verification by tandem mass spectrometry provides stronger evidence than a single mass measurement. For any study reporting biological results, the analytical method and the measured purity should be stated explicitly. Independent verification of supplier claims is considered good practice.
Semax is supplied as a lyophilized powder that appears white to off-white. It dissolves readily in water, phosphate-buffered saline, and other aqueous media, which simplifies preparation of working solutions for laboratory use. The nasal products registered in Russia are dilute aqueous solutions, typically around 0.1 percent peptide by weight. Organic solvents are rarely necessary and can complicate handling. Because the peptide is hygroscopic, weighing should be performed quickly and with minimal exposure to ambient humidity.
The compound is registered in Russia as a pharmaceutical product, most commonly formulated as a nasal solution, and has been used in that setting since the 1990s. Outside that jurisdiction it is generally handled as a research chemical rather than an approved medicine. Regulatory status therefore differs sharply between countries, and material sold internationally may not correspond to the Russian pharmaceutical formulation. Documentation with commercial samples is typically limited to a certificate of analysis covering purity and identity, not clinical status or local legal classification.
Semax is a synthetic heptapeptide with the sequence Met-Glu-His-Phe-Pro-Gly-Pro. It corresponds to the ACTH(4-7) fragment extended at the C-terminus by a Pro-Gly-Pro tripeptide, an addition intended to slow enzymatic breakdown. The molecular formula is C37H51N9O10S and the molecular mass is approximately 814 daltons. In the literature it is often described as an ACTH(4-10) analog, although that label reflects a naming convention as much as a precise structural relationship. The compound was developed in Russia and remains most closely associated with that research tradition.
| Property | Value | Notes |
|---|---|---|
| Typical purity | ≥95% by HPLC | Research-grade material |
| Detection wavelength | 214 nm | Peptide bond absorbance |
| Reconstitution medium | Sterile water or saline | Prepare fresh or aliquot immediately |
| Storage (solution) | -80 °C, single-use aliquots | Avoid repeated freeze-thaw cycles |
| Common salt form | Acetate or trifluoroacetate | Affects mass and solubility |
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.
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.
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.
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.
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.
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。
It remains relatively common in sub-Saharan Africa. Outbreaks have been seen in refugee camps. Thiamine deficiency has been described for thousands of years in Asia, and became more common in the late 1800s with the increased processing of rice.
Rockefeller Benjamin Jealous (1994), president of the NAACP Ai-jen Poo (1996), activist, recipient of the MacArthur Fellowship in 2014 Risë Wilson (1997), activist Anna Baltzer (2002), activist for Palestinian human rights Ady Barkan (2006), activist and organizer for Center for Popular Democracy Tourmaline (2006), activist and filmmaker Emma Sulkowicz (2015), performance activist known for Mattress Performance (Carry That Weight) and Ceci N'est Pas Un Viol Coleman Hughes (2020), activist and writer on issues of race and racism Henry Williams (2022), political activist and chief of staff of the Mike Gravel 2020 presidential campaign
==== Increasing mandatory tests in California ==== Many rare diseases have not historically been tested for or testing that has been available has not been mandatory. One such disease is glutaric acidemia type I, a neurometabolic disease present in approximately 1 out of every 100,000 live births. A short-term California testing pilot project in 2003 and 2004 demonstrated the cost of forgoing rare disease testing on newborns. While both Zachary Wyvill and Zachary Black were both born with the same disease during the pilot program, Wyvill's birth hospital tested only for four state-mandated diseases while Black was born at a hospital participating in the pilot program. Wyvill's disease went undetected for over six months during which irreversible damage occurred but Black's disease was treated with diet and vitamin supplements. Both sets of parents became advocates for expanded neonatal testing and testified in favor of expanding tandem mass spectrometry (MS/MS) testing of newborns for rare diseases. By August, 2004, the California state budget law had passed requiring the use of tandem mass spectroscopy to test for more than 30 genetic illnesses and provided funding. California now mandates newborn screening for all infants and tests for 80 congenital and genetic disorders.
== History and programs == GAVI was created in 2000 as a successor to the Children's Vaccine Initiative, which was launched in 1990. In August 2014, Gavi changed its name from "GAVI Alliance" and rebranded itself with a new logo deliberately reminiscent of UN organization logos, but using green as a mark of difference. As mentioned above, Gavi plans its operations in terms of five-year stretegies to make it easier to negotiate longer-term deals. Gavi 6.0 (2026–2030) was approved by the Gavi board in June 2024. One of the goals is to build country-led, sustainable vaccination programs.
The Israel Defense Forces "battle ration" (Manat Krav) is designed to be shared by four soldiers. It contains 1 can of rice filled vine leaves, 8 small cans of tuna, canned olives, a can of sweet corn, a can of pickled cucumbers, 1 can of halva spread and 1 chocolate spread, a can of peanuts, fruit flavored drink powder, and bread or matzoh crackers. There is also an "ambush pack" of candy and high-energy protein bars. In 2008, Israel introduced a new field ration to supplement the traditional Manat Krav. Unlike previous rations, the new Battle Ration consists of individual, self-heating, ready-to-eat meals packed inside plastic-aluminum trays. They are designed to be carried and used by infantry troops for up to 24 hours, until regular supply lines can be established. Ten menus are available, including chicken, turkey and kebab; each meal pack is supplemented with dry salami, dried fruit, tuna, halva, sweet roll, and preserved dinner rolls. However, as of 2012, the older rations were still in use. In 2011, as a result of the manufacturer going bankrupt, the IDF phased out the can of corned beef (known as 'Loof'), which had been part of the battle ration since the nation's founding. It would be replaced by "ground meat with tomato sauce". Many different recipes and different ways of serving the rations have developed in Israel. With the can of tuna, for example, traditionally cooked using toilet paper soaked in oil.
Sources: en.wikipedia.org
granulated diatomaceous earth is a raw material simply crushed for convenient packaging milled or micronized diatomaceous earth is especially fine (10 μm to 50 μm) and used for insecticides calcined diatomaceous earth is heat-treated and activated for filters
Glucose enters the β-cells through the glucose transporters, GLUT 2. At low blood sugar levels little glucose enters the β-cells; at high blood glucose concentrations large quantities of glucose enter these cells. The glucose that enters the β-cell is phosphorylated to glucose-6-phosphate (G-6-P) by glucokinase (hexokinase IV) which is not inhibited by G-6-P in the way that the hexokinases in other tissues (hexokinase I – III) are affected by this product. This means that the intracellular G-6-P concentration remains proportional to the blood sugar concentration. Glucose-6-phosphate enters glycolytic pathway and then, via the pyruvate dehydrogenase reaction, into the Krebs cycle, where multiple, high-energy ATP molecules are produced by the oxidation of acetyl CoA (the Krebs cycle substrate), leading to a rise in the ATP:ADP ratio within the cell. An increased intracellular ATP:ADP ratio closes the ATP-sensitive SUR1/Kir6.2 potassium channel (see sulfonylurea receptor). This prevents potassium ions (K+) from leaving the cell by facilitated diffusion, leading to a buildup of intracellular potassium ions. As a result, the inside of the cell becomes less negative with respect to the outside, leading to the depolarization of the cell surface membrane. Upon depolarization, voltage-gated calcium ion (Ca2+) channels open, allowing calcium ions to move into the cell by facilitated diffusion. The cytosolic calcium ion concentration can also be increased by calcium release from intracellular stores via activation of ryanodine receptors.
Wright's invention did not lead to any further developments, and diamorphine became popular only after it was independently re-synthesized 23 years later by chemist Felix Hoffmann. Hoffmann was working at Bayer pharmaceutical company in Elberfeld, Germany, and his supervisor Heinrich Dreser instructed him to acetylate morphine with the objective of producing codeine, a constituent of the opium poppy that is pharmacologically similar to morphine but less potent and less addictive. Instead, the experiment produced an acetylated form of morphine one and a half to two times more potent than morphine itself. Hoffmann synthesized heroin on 21 August 1897, just eleven days after he had synthesized aspirin. The head of Bayer's research department reputedly coined the drug's new name of "heroin", based on the German heroisch which means "heroic, strong" (from the ancient Greek word "heros, ήρως"). Bayer scientists were not the first to make heroin, but their scientists discovered ways to make it, and Bayer led the commercialization of heroin. Bayer marketed diacetylmorphine as an over-the-counter drug under the trademark name Heroin. It was developed chiefly as a morphine substitute for cough suppressants that did not have morphine's addictive side-effects. Morphine at the time was a popular recreational drug, and Bayer wished to find a similar but non-addictive substitute to market. However, contrary to Bayer's advertising as a "non-addictive morphine substitute", heroin would soon have one of the highest rates of addiction among its users.
Understanding the igneous petrology of monazite is important to be able to date the crystallisation age of igneous rocks. Monazite is commonly present as an accessory mineral in low-CaO peraluminous granitoids, from diorites, micaceous granites to pegmatites. The reason for the low CaO content is probably that melts with high CaO content promote the formation of apatite and allanite but not monazite. It is commonly formed from magmatism involving carbonatic melts but not mafic plutons or lavas. Those rocks usually host economic REE ore deposits, making monazite geochronology important in mining exploration. The simplest monazite zonation showing successive crystallisation of melts is concentric zonation, in which new monazite layers are crystallized rim-by-rim around the pre-existing core. The rims often show compositional variations due to the preferential incorporation of certain elements in the crystal lattice. For example, considering a closed system, Th is preferentially incorporated into the monazite mineral structure, leaving a Th-depleted melt. Therefore, older monazite near the core of a grain is rich in Th while younger monazite contains less, resulting in a rimward decrease of Th in a concentric zoning pattern. Investigating composition and age variation of these rims help to constrain the timing and rate of crystallisation as well as the composition of the melt, especially for rocks where zircon is not present.
Economist Adam Hanieh argues that, in the post-WWII era, the global capitalist system was destabilized by a wave of decolonization movements that swept through Africa, Asia, and Latin America. According to historian L. S. Stavrianos, inspired by the Soviet Union’s rapid socioeconomic progress, numerous revolutionary governments subsequently implemented state-planned economies and public ownership. In his autobiography, the former Prime Minister of India, Jawaharlal Nehru, proclaimed that "the presence and example of the Soviets was a bright and heartening phenomenon in a dark and dismal world." Political scientist Michael Parenti argues that these revolutionary governments implemented land reform and comprehensive programs for health, education, housing, and employment. By addressing the legacies of colonial exploitation and extreme poverty, he writes, these initiatives resulted in a historically unprecedented rise in the standard of living for hundreds of millions of people. Economist Samir Amin contends that these revolutionary governments also achieved progress in industrialization, economic equality, and the construction of modern states. According to economist Alice Amsden, World Bank data reveal a historic trend between 1950 and 1980: for the first time in recorded history, developing economies outpaced developed economies, achieving an average annual income growth of over 5% compared to 4% in the developed economies.
Sources: en.wikipedia.org
Solid peptide is best kept frozen at about minus 20 degrees Celsius in a sealed container with desiccant. It should be allowed to reach room temperature before opening to prevent condensation. Repeated warming and cooling of the same vial is discouraged.
Reversed-phase liquid chromatography establishes purity, while mass spectrometry confirms molecular mass. The two techniques are normally used together. Retention time alone is not sufficient evidence of identity.
Different counterions change the mass per unit of peptide and can shift chromatographic behavior. Two samples of equal stated purity may therefore not be directly comparable. Reports should specify the counterion whenever quantitative comparisons are made.
It is registered as a pharmaceutical product in Russia, where it is typically supplied as a nasal solution. In most other countries it is not an approved drug and is traded as a research chemical instead. Approval status depends entirely on the jurisdiction involved.