lyophilised powder comes up often in conversation and rarely with the context attached. Here we lay out the basics in order, then work through the practical considerations.
Last reviewed on 2025-09-22. Where a claim depends on a specific study, the study is described rather than over-claimed.
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.
Laboratory descriptions of the material are consistent across suppliers. It appears as a white to off-white lyophilized powder that dissolves readily in water and in polar organic solvents such as dimethyl sulfoxide. Aqueous solutions are clear and colorless at low concentrations. Because the peptide contains methionine, oxidation at the sulfur atom is a recognized degradation pathway, and handling notes usually call for protected, desiccated storage. Reported purity for research-grade lots is generally above 95 percent as measured by reversed-phase high-performance liquid chromatography.
Identity and purity are confirmed with reversed-phase high-performance liquid chromatography, typically monitored at 214 nanometres where the peptide bond absorbs. Mass spectrometry, either electrospray or MALDI-TOF, verifies molecular mass against the theoretical value and detects truncation or adduct formation. Amino acid analysis and peptide mapping provide additional confirmation when required. The most frequently reported impurities are deletion sequences from incomplete coupling, methionine sulfoxide from oxidation, and dimeric species formed through non-covalent aggregation. Impurity profiles depend strongly on the synthesis and purification route chosen by the producer.
Published research has focused mainly on neurological and cognitive endpoints in animal models, with proposed mechanisms involving brain-derived neurotrophic factor and related signalling pathways. A substantial share of the human data originates from a limited number of research groups, and independent replication in other countries remains sparse. Regulatory status reflects that distribution: the peptide is registered as a medicine in Russia and appears in some neighbouring markets, while elsewhere it is handled as a research chemical without approved therapeutic labelling. Questions about dose-response relationships, long-term effects, and comparability across studies are still open.
| Property | Value | Notes |
|---|---|---|
| Molecular formula | C37H51N9O10S | Contains one methionine sulfur atom |
| Molecular mass | Approximately 814 Da | Consistent with a seven-residue peptide |
| Appearance | White to off-white powder | Typical lyophilized form |
| Solubility | Freely soluble in water | Also soluble in dimethyl sulfoxide |
| Typical storage | -20 °C, desiccated | Limits methionine oxidation |
各国监管态度分化明显。俄罗斯按处方药管理，部分东欧国家留有使用记录；欧盟与美国未批准其作为药物上市，市面流通品通常标注为研究用化学品。身份差异意味着标示含量、纯度与无菌性缺少统一核查。体育领域还牵涉反兴奋剂名录，跨境携带则受目的地药品法规约束。
Semax 是人工设计的七肽，序列为 Met-Glu-His-Phe-Pro-Gly-Pro，骨架取自促肾上腺皮质激素片段 ACTH(4-10)。它于二十世纪八十年代在苏联的分子遗传学研究机构内合成。设计目标是保留该片段与注意力和记忆相关的活性，同时剔除促皮质激素释放等内分泌作用。此后俄罗斯将其登记为药品并进入临床使用。
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.
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.
The Dirty Drug and the Ice Cream Tub Radiolab episode on the discovery of rapamycin Clinical trial number NCT02494570 for "A Phase 2 Study of ABI-009 in Patients With Advanced Malignant PEComa (AMPECT)" at ClinicalTrials.gov
=== Producing sulfuric acid from sulfur === A method of producing oleum sulphuris per campanam, or "oil of sulfur by the bell", was known by the 16th century: it involved burning sulfur under a glass bell in moist weather (or, later, under a moistened bell). However, it was very inefficient (according to Gesner, 5 pounds (2.3 kg) of sulfur converted into less than 1 ounce (0.03 kg) of acid), and the resulting product was contaminated by sulfurous acid (or rather, solution of sulfur dioxide) so most alchemists (including Isaac Newton) did not consider it equivalent to "oil of vitriol". In the 17th century, Johann Rudolf Glauber discovered that adding saltpeter (potassium nitrate, KNO3) and replacing moisture with steam significantly improves the output. As saltpeter decomposes, it oxidizes the sulfur to SO3, which combines with water to produce sulfuric acid. In 1736, Joshua Ward, a London pharmacist, used this method to begin the first large-scale production of sulfuric acid.
Plant physiology encompasses all the internal chemical and physical activities of plants associated with life. Chemicals obtained from the air, soil and water form the basis of all plant metabolism. The energy of sunlight, captured by oxygenic photosynthesis and released by cellular respiration, is the basis of almost all life. Photoautotrophs, including all green plants, algae and cyanobacteria gather energy directly from sunlight by photosynthesis. Heterotrophs including all animals, all fungi, all completely parasitic plants, and non-photosynthetic bacteria take in organic molecules produced by photoautotrophs and respire them or use them in the construction of cells and tissues. Respiration is the oxidation of carbon compounds by breaking them down into simpler structures to release the energy they contain, essentially the opposite of photosynthesis. Molecules are moved within plants by transport processes that operate at a variety of spatial scales. Subcellular transport of ions, electrons and molecules such as water and enzymes occurs across cell membranes. Minerals and water are transported from roots to other parts of the plant in the transpiration stream. Diffusion, osmosis, and active transport and mass flow are all different ways transport can occur. Examples of elements that plants need to transport are nitrogen, phosphorus, potassium, calcium, magnesium, and sulphur. In vascular plants, these elements are extracted from the soil as soluble ions by the roots and transported throughout the plant in the xylem.
== Move to United States == In 1951, Szathmary emigrated to the United States, arriving in New York City from Bremerhaven speaking no English, with $1.10 in his pocket. Once there, he found work as a short-order cook and worked his way up through the ranks, honing his skills until he catered to the East Coast's elite. In 1959, he moved to Chicago to work for Armour and Company, where he developed frozen food lines for various food companies, including Stouffer Corporation. Stouffer's classic Frozen Spinach Souffle is one of Szathmary's creations. He continued to pioneer the rapidly changing food industry, working with new ideas including freeze drying and boil-in bags. Some of Szathmary's creations were used by NASA and accompanied astronauts in space.
Sources: en.wikipedia.org
There have been several enantioselective versions of this reaction developed, and even employed in synthesis of complex molecules. Hoyveda's synthesis of (R)-(-)-sporochnol included an asymmetric copper-catalyzed allylic substitution with an organozinc nucleophile and peptide ligand. A TaniaPHOS ligand, a ferrocenylphosphine, is used with a methyl Grignard nucleophile to form an allylic stereocenter towards the total synthesis of (S)-(-)-Zearalenone
=== Equity === Digital agriculture shows promise for creating a more equitable agri-food value chain. Because digital technologies reduce transaction costs and information asymmetries, they can improve smallholder farmers' market access in a number of ways:
== SR == sr – (s) Serbian language (ISO 639-1 code) Sr – (s) Strontium SR (i) Sound Reinforcement Supply Route (s) Suriname (ISO 3166 digram) (i) Sveriges Radio (Swedish Radio Ltd) SR – (i) Sustained release of a drug SRAM (p) Scott (King), Ray (Day), SAM (Patterson) — founders of bicycle component manufacturer SRAM Corporation (p) Static Random Access Memory ("ess-ram") SR-ATGW – (i) Short-Range Anti-Tank Guided Weapon SRB – (i) Solid Rocket Booster SRBM – (i) Short-Range Ballistic Missile (cf. IRBM, ICBM) SRC – (i) Scheduled Removal Component srd – (s) Sardinian language (ISO 639-2 code) SRD (i) Science Requirements Document (s) Surinam dollar (ISO 4217 currency code) SRE - (i) Site Reliability Engineer(ing) SREL – (i) Savannah River Ecology Laboratory SRG (i) SACEUR Rover Group Special Republican Guard SRGW – (i) Short-Range Guided Weapon SRL (i) Savannah River Laboratory Single Rocket Launcher Survival Research Labs SRM – (i) Specified Risk Material(s) srp – (s) Serbian language (ISO 639-2 code) SRS – (i) Savannah River Site SRTP – (i) [Secure Real-time Transport Protocol]
=== Paleobiology === Fungi are composed of soft tissues, making fossilization difficult and the discovery of fungal fossils rare. However, some exquisitely preserved specimens have been discovered in the middle Eocene Princeton Chert of British Columbia. These ectomycorrhizal fossils show clear evidence of a Hartig net, mantle and hyphae, demonstrating well-established EcM associations at least 50 million years ago. The fossil record shows that the more common arbuscular mycorrhizas formed long before other types of fungal-plant symbioses. Ectomycorrhizas may have evolved with the diversification of plants and the evolution of conifers and angiosperms. Arbuscular mycorrhizas may thus have been a driving force in the plant colonization of land, while ectomycorrhizas may have arisen either in response to further speciation as the Earth's climate became more seasonal and arid, or perhaps simply in response to nutritionally deficient habitats.
In his widely awaited first speech since the start of the war in Gaza on 3 November, Hezbollah leader Hassan Nasrallah said the presence of U.S. warships in the Mediterranean "doesn't scare us". On 5 November, Hezbollah shot down an Israeli Elbit Hermes 450 drone over Nabatieh, with wreckage falling over houses in the towns of Zabdin and Harouf. One Israeli civilian was killed when anti-tank missiles hit the Yiftah kibbutz. Four people were reportedly injured after an Israeli bombing that hit two ambulances. Later, an Israeli airstrike hit two civilian cars in Lebanon between the towns of Aynata and Aitaroun, killing one woman, three of her granddaughters between the ages of 10 and 14, and severely injured her daughter. In response, Hezbollah fired at Kiryat Shmona, killing an Israeli civilian. The Al-Qassam Brigades took responsibility for firing 16 rockets from Lebanon targeting areas south of Haifa. Meanwhile, Israel reported at least 30 rockets being fired in which the IDF fired back at the sources. Hezbollah and Al-Qassam brigades also conducted four cross-border attacks into northern Israel. Hezbollah deputy general Naim Qassem said that the group could be forced into wider conflict over Israeli attacks in Gaza. On 10 November, Hezbollah launched anti-tank missiles into an IDF post in Manara which injured three soldiers. The IDF attacked the sources of fire in response. Hezbollah conducted three drone attacks into northern Israel targeting IDF positions and civilians. One drone was intercepted while two others landed on Israeli territory.
Sources: en.wikipedia.org
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.
Most published work uses intranasal administration, matching the route of the registered Russian formulation. Some animal experiments use intravenous or intraperitoneal injection. The route matters because the intact peptide is cleared rapidly from blood, so exposure differs between methods.
A purity value describes the share of the powder accounted for by the target peptide, usually by high-performance liquid chromatography. It does not confirm that the sequence is correct, which requires mass spectrometry or amino acid analysis. Purity and identity are separate checks.
Reversed-phase HPLC gives the main purity figure, most often with UV detection near 214 nanometres. Mass spectrometry then confirms the molecular mass. Together the two methods distinguish a correct sequence from a closely related impurity.