This is a working overview of Lyophilized powder, written for readers who want more than a one-paragraph summary but less than a textbook.
Reviewed 2026-08-01. 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。
Development is attributed to researchers at the Institute of Molecular Genetics in Moscow during the early 1980s, building on earlier Soviet work with ACTH fragments. Russian regulatory approval followed for intranasal use, and the compound has remained commercially available there for decades. Most published human data originate from Russian and, later, some Eastern European clinical reports, which are not always accessible in English translation. Outside that region the material is generally handled as a research chemical rather than a licensed medicine.
Regulatory status differs sharply between jurisdictions. In Russia the peptide is registered as a prescription nasal preparation, while agencies such as the United States Food and Drug Administration have not approved it for any indication. Products sold elsewhere are typically labeled for laboratory research only, and such labels shift responsibility for safe handling to the purchaser. Because the same name covers pharmaceutical-grade nasal drops and bulk research powder, identity and purity documentation becomes the main practical concern when comparing sources.
Semax is a synthetic seven-amino-acid peptide whose sequence extends the ACTH(4-10) fragment with a C-terminal proline-glycine-proline tripeptide. The commonly cited sequence is Met-Glu-His-Phe-Pro-Gly-Pro, giving a molecular formula near C37H51N9O10S and a molecular weight close to 813.9 g/mol. It belongs to the broader class of synthetic ACTH fragments studied for central nervous system effects rather than for adrenal steroid stimulation. In practice the material appears as a lyophilized white powder for laboratory work or as a dilute saline solution in clinical settings.
| 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 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.
Lyophilized material is chemically stable for extended periods when kept dry, cold, and protected from light. The powder is hygroscopic, so vials should be warmed to room temperature before opening to reduce condensation on the contents. Once dissolved, the peptide is far less stable because peptide bonds are susceptible to hydrolysis and the methionine residue can oxidize. Solutions are typically aliquoted and held at 2-8 °C for short intervals or frozen for longer ones, and repeated freeze-thaw cycles should be avoided.
Routine characterization relies on reversed-phase high-performance liquid chromatography to establish purity and on mass spectrometry to confirm molecular identity. Electrospray ionization and matrix-assisted laser desorption ionization are both used for mass verification. Amino acid analysis and peptide mapping can detect sequence errors. Common impurities include truncated sequences, methionine sulfoxide formed by oxidation, and deamidated products. Chromatograms are usually recorded near 214 nm, where the peptide backbone absorbs, and purity is reported as the percentage area of the principal peak.
Russian regulatory authorities approved the peptide for nasal administration, and it remains listed in the national pharmacopoeia under several trade names. Documented indications include acute ischemic stroke, transient ischemic attacks, traumatic brain injury, and certain ophthalmological and neurological conditions. Physicians also prescribe it for cognitive complaints in older patients, although the evidence base for that use is thinner. Outside Russia and a few neighboring states, the substance is not an approved medicine and is sold instead as a research chemical.
Later generations of the molecule include an N-acetylated form and an amidated form, both marketed online alongside the parent peptide. These variants differ in terminal chemistry and stability, and they are frequently discussed in the same breath even though they have not been compared in controlled trials. Supply outside formal healthcare systems comes largely from laboratories that synthesize peptides to order. Purity and identity of these materials vary widely, and no single body oversees the international trade.
=== Toxicology data === In the 1990s, fialuridine (FIAU) was investigated in clinical trials. The first trial was a 10-day trial in which 43 patients, who were infected with HIV and hepatitis B, demonstrated effective antiviral activity. A subsequent second dose-ranging study was done on 24 patients with hepatitis B over a period of four weeks. The second trial showed significant viral suppression at intermediate doses. However, patients later relapsed, meaning that the viral infection had returned. A longer, 6-month NIH-sponsored, third trial was planned to be conducted, but severe toxicity emerged at patients who had participated in the second trial. Many severe and fatal adverse effects were reported, including lactic acidosis, acute liver failure, peripheral neuropathy, multiple organ failure, and mitochondrial toxicity. A 60-year-old patient died from liver failure and lactic acidosis four months after the second trial. During the third trial, many patients experienced unpleasant side effects such as nausea and vomiting to such an extent that the researchers decided to end the trial. A theory put forward by Dr. Yung-Chi Chang of Yale University in 1991, which hypothesize that FIAU damaged the mitochondrial DNA, thereby giving rise to delayed toxicity. Urgent attempts were subsequently made to counteract the loss of mitochondria. However, by July 16, three patients had died, of whom two had already received a liver transplant and one was waiting for one. By August 1993, two more patients reported to be gravely ill and two other patients had also died.
This method has been described as the most viable means of disposing of radioactive waste, and as the state-of-the-art as of 2001 in nuclear waste disposal technology. Another approach termed Remix & Return would blend high-level waste with uranium mine and mill tailings down to the level of the original radioactivity of the uranium ore, then replace it in inactive uranium mines. This approach has the merits of providing jobs for miners who would double as disposal staff, and of facilitating a cradle-to-grave cycle for radioactive materials, but would be inappropriate for spent reactor fuel in the absence of reprocessing, due to the presence of highly toxic radioactive elements such as plutonium within it. Deep borehole disposal is the concept of disposing of high-level radioactive waste from nuclear reactors in extremely deep boreholes. Deep borehole disposal seeks to place the waste as much as 5 kilometres (3.1 mi) beneath the surface of the Earth and relies primarily on the immense natural geological barrier to confine the waste safely and permanently so that it should never pose a threat to the environment. The Earth's crust contains 120 trillion tons of thorium and 40 trillion tons of uranium (primarily at relatively trace concentrations of parts per million each adding up over the crust's 3 × 1019 ton mass), among other natural radioisotopes.
GLP1 poly-agonist peptides are a class of drugs that activate multiple peptide hormone receptors including the glucagon-like peptide-1 (GLP-1) receptor. These drugs are developed for the same indications as GLP-1 receptor agonists—especially obesity, type 2 diabetes, and non-alcoholic fatty liver disease. Unlike GLP-1 mono-agonists, which target only the GLP-1 receptor, poly-agonists activate two or more incretin receptors, such as the gastric inhibitory polypeptide (GIP) receptor, which have distinct features but work together in metabolic regulation. GIP and GLP-1 are both naturally released from the gastrointestinal tract after eating, but act on different receptor distributions across tissues. GLP-1 receptors are concentrated in the pancreas, brain, and gastrointestinal tract, while GIP receptors are found primarily in the pancreas, brain, and adipose tissue. In healthy people, the combined incretin effect of GIP and GLP-1 accounts for around 50–70% of post-meal insulin secretion. This effect is substantially reduced in people with type 2 diabetes, providing evidence for therapies that activate both hormones. Poly-agonists are expected to provide superior efficacy with fewer adverse effects compared to GLP-1 mono-agonists, which are dose-limited by gastrointestinal disturbances. The effectiveness of multi-receptor agonists could possibly equal or exceed that of bariatric surgery. The first such drug to receive approval is tirzepatide, a dual agonist of GLP-1 and GIP receptors.
Canning is a method of food preservation in which food is processed and sealed in an airtight container (jars like Mason jars, and steel and tin cans). Canning provides a shelf life that typically ranges from one to five years, although under specific circumstances, it can be much longer. A freeze-dried canned product, such as canned dried lentils, could last as long as 30 years in an edible state. In 1974, samples of canned food from the wreck of the Bertrand, a steamboat that sank in the Missouri River in 1865, were tested by the National Food Processors Association. Although appearance, smell, and vitamin content had deteriorated, there was no trace of microbial growth and the 109-year-old food was determined to be still safe to eat.
Sources: en.wikipedia.org
Luteinizing hormone is available mixed with FSH in the form of menotropin, and other forms of urinary gonadotropins. More purified forms of urinary gonadotropins may reduce the LH portion in relation to FSH. Recombinant luteinizing hormone is available as lutropin alfa (Luveris).
When the rats were exposed to a bacterial substance that should induce keratitis of the cornea, the amount of inflammation in the treatment group of rats (received the eye drops after exposure) was inhibited. Magnetic nanoparticles have also been used in hyperthermic therapy of cancer, cell purification, biosensing, and immunocytochemical tests.
An example is the trp gene in bacteria. When there is a high level of tryptophan in the region, it is inefficient for the bacterium to synthesize more. When the RNA polymerase binds and transcribes the trp gene, the ribosome will start translating. (This differs from eukaryotic cells, where RNA must exit the nucleus before translation starts.) The attenuator sequence, which is located between the mRNA leader sequence (5' UTR) and trp operon gene sequence, contains four domains, where domain 3 can pair with domain 2 or domain 4. The attenuator sequence at domain 1 contains instruction for peptide synthesis that requires tryptophans. A high level of tryptophan will permit ribosomes to translate the attenuator sequence domains 1 and 2, allowing domains 3 and 4 to form a hairpin structure, which results in termination of transcription of the trp operon. Since the protein coding genes are not transcribed due to rho independent termination, no tryptophan is synthesised. In contrast, a low level of tryptophan means that the ribosome will stall at domain 1, causing the domains 2 and 3 to form a different hairpin loop structure that does not signal termination of transcription. Therefore, the rest of the operon will be transcribed and translated, so that tryptophan can be produced. Thus, domain 4 is an attenuator. Without domain 4, translation can continue regardless of the level of tryptophan. The attenuator sequence has its codons translated into a leader peptide, but is not part of the trp operon gene sequence.
Sources: en.wikipedia.org
Horsepox is extinct in the wild, and the only known sample was collected in 1976. Because the sample was collected at the end of the smallpox eradication campaign, scientists considered the possibility that horsepox is a strain of vaccinia that had escaped into the wild. However, as more smallpox vaccines were sequenced, older vaccines were found to be more similar to horsepox than modern vaccinia strains. A smallpox vaccine manufactured by Mulford in 1902 is 99.7% similar to horsepox, closer than any previously known strain of vaccinia. Modern Brazilian vaccines with a documented introduction date of 1887, made from material collected in an 1866 outbreak of "cowpox" in France, are more similar to horsepox than other strains of vaccinia. Five smallpox vaccines manufactured in the United States in 1859–1873 are most similar to each other and horsepox, as well as the 1902 Mulford vaccine. One of the 1859–1873 vaccines was identified as a novel strain of horsepox, containing a complete gene from the 1976 horsepox sample that has deletions in vaccinia.
Hegseth was sworn in as the secretary of defense by JD Vance on January 25. Hegseth identified several priorities for the Department of Defense, including to "revive the warrior ethos", restore trust in the military, redevelop the nation's industrial base, ease the department's process to purchase weaponry, defend the US domestically, engage with Indo-Pacific to deter China, and support Trump's effort to "end wars responsibly"—including the Russo-Ukrainian War and the Middle Eastern crisis. In a call to Israeli prime minister Benjamin Netanyahu a day after being sworn in, Hegseth said that the United States was "fully committed" to the security of Israel. Hegseth revoked the security clearance and detail of Mark Milley, the former chairman of the Joint Chiefs of Staff and chief of staff of the Army who later became a critic of Trump, and ordered an inspector general inquiry into Milley's tenure as chairman of the Joint Chiefs of Staff; the inspector general of the Department of Defense, Robert Storch, was removed from his position when Trump dismissed several inspectors general. According to The Washington Post, the Department of Defense Education Activity began removing certain books on immigration and sexuality. Hegseth visited the Mexico–United States border with Tom Homan, Trump's border czar, in El Paso, Texas, in February, where he stated that the federal government intended to gain complete "operational control of the southern border". He renamed Fort Liberty to Fort Bragg, its original name honoring the Confederate general Braxton Bragg.
==== Phosphodiesterase PDE5 inhibitors ==== Avanafil (Razatus; Spedra; Stendra; TA-1790; Zepeed) – phosphodiesterase PDE5 inhibitor – erectile dysfunction [114] Lodenafil (CRIS-031; Helleva) – phosphodiesterase PDE5 inhibitor – erectile dysfunction [115] Mirodenafil (Aibishi; Bravonto; Mvix; SK-3530) – phosphodiesterase PDE5 inhibitor – erectile dysfunction [116] Sildenafil (Revatio; Revatio IV; UK-92480; Viagra) – phosphodiesterase PDE5 inhibitor – erectile dysfunction [117] Sildenafil chewable tablets (Nurigra) – phosphodiesterase PDE5 inhibitor – erectile dysfunction [118] Sildenafil orally soluble film (sildenafil ODF; SPO-1101; Vultis) – phosphodiesterase PDE5 inhibitor – erectile dysfunction [119] Sildenafil orally soluble film (orodispersible sildenafil; Please; sildenafil oral dissolving film; sildenafil orally-disintegrating film; sildenafil OSF) – phosphodiesterase PDE5 inhibitor – erectile dysfunction [120] Sildenafil oral spray (ASP-001; ASP-002; Bandol; Hezkue) – phosphodiesterase PDE5 inhibitor – erectile dysfunction [121] Sildenafil oro-dispersible tablets (Erecta; FACSID-50) – phosphodiesterase PDE5 inhibitor – erectile dysfunction [122] Simmerafil (Onvita; Onweida; semenafil; TPN-171; TPN-171-H) – phosphodiesterase PDE5 inhibitor – erectile dysfunction [123] Tadalafil (Adcirca; Cialis; GF-196960; IC-351; LY-450190; Zalutia) – phosphodiesterase PDE5 inhibitor – erectile dysfunction [124] Tadalafil oral disintegrating film (SPO-1102; Vulteum; tadalafil ODF) – phosphodiesterase PDE5 inhibitor – erectile dysfunction [125] Tadalafil oral film (OGOOD) – phosphodiesterase PDE5 inhibitor – erectile dysfunction [126] Udenafil (DA-8159; Jurvigo; ME-3113; MZ101; Udzire; WC-3043; WC-3055; Zydena) – phosphodiesterase PDE5 inhibitor – erectile dysfunction [127] Vardenafil (BAY-389456; Levitra; Nuviva; Staxyn; vardenafil ODT; vardenafil orodispersible tablet; Vivanza) – phosphodiesterase PDE5 inhibitor – erectile dysfunction [128]
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。
It is a short synthetic peptide built from seven amino acids: methionine, glutamic acid, histidine, phenylalanine and three prolines. The sequence derives from the 4-10 fragment of adrenocorticotropic hormone with an added proline-glycine-proline tail. No plant or animal extract is involved; the material is produced by solid-phase peptide synthesis.