peptide synthesis 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 2025-12-21. Where a claim depends on a specific study, the study is described rather than over-claimed.
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。
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。
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.
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.
| Property | Value | Notes |
|---|---|---|
| 化学类别 | 合成七肽 | ACTH(4-10) 结构类似物 |
| 氨基酸序列 | Met-Glu-His-Phe-Pro-Gly-Pro | 单字母写作 MEHFPGP |
| 分子量 | 约 813.9 Da | 随确切形式和盐型略有变化 |
| 常见同义词 | ACTH(4-10) 类似物 | 俄语文献称 Семакс |
| 开发来源 | 俄罗斯 | 二十世纪八十年代 |
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.
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.
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.
Terminology around the compound varies by source. It appears in catalogues and papers as Semax, as the heptapeptide ACTH(4-7)-Pro-Gly-Pro, and under various alphanumeric laboratory codes used by individual suppliers. These names refer to the same sequence but may imply different salt forms, purity grades, or counter-ions. Peptide databases usually list the free base mass, while product descriptions sometimes report acetate or trifluoroacetate salts with a different formula weight. Because naming conventions for research peptides are not standardised across vendors, checking the declared sequence and measured mass is more reliable than relying on a trade name alone.
Semax is a synthetic heptapeptide with the sequence Met-Glu-His-Phe-Pro-Gly-Pro. Its design combines the ACTH(4-7) core fragment with a C-terminal Pro-Gly-Pro extension, a modification intended to improve stability and prolong activity. The molecule is hydrophilic, carries no lipid chains or glycosylation, and has a theoretical mass just over 810 daltons in its free form. All seven residues are proteinogenic amino acids, so no non-natural building blocks appear in the backbone. A free N-terminal methionine and C-terminal proline define the unmodified parent peptide.
The compound was developed during the 1980s at the Institute of Molecular Genetics in Moscow as part of research on fragments of adrenocorticotropic hormone. Early work examined short ACTH-derived sequences that retained neurotrophic effects while lacking the endocrine activity of the full hormone. Semax entered clinical use in Russia during the 1990s, where it received registration for several neurological indications. Outside that region it remained primarily a laboratory research material rather than an approved therapeutic. English-language literature on it grew more slowly and frequently cited the original Russian studies.
Although benzodiazepines are much safer in overdose than their predecessors, the barbiturates, they can still cause problems in overdose. Taken alone, they rarely cause severe complications in overdose; statistics in England showed that benzodiazepines were responsible for 3.8% of all deaths by poisoning from a single drug. However, combining these drugs with alcohol, opiates or tricyclic antidepressants markedly raises the toxicity. The elderly are more sensitive to the side effects of benzodiazepines, and poisoning may even occur from their long-term use. The various benzodiazepines differ in their toxicity; temazepam appears most toxic in overdose and when used with other drugs. The symptoms of a benzodiazepine overdose may include; drowsiness, slurred speech, nystagmus, hypotension, ataxia, coma, respiratory depression, and cardiorespiratory arrest. A reversal agent for benzodiazepines exists, flumazenil (Anexate), itself belonging to the chemical class of benzodiazepines. Its use as an antidote is not routinely recommended because of the high risk of resedation and seizures. In a double-blind, placebo-controlled trial of 326 people, 4 people had serious adverse events and 61% became resedated following the use of flumazenil. Numerous contraindications to its use exist. It is contraindicated in people with a history of long-term use of benzodiazepines, those having ingested a substance that lowers the seizure threshold or may cause an arrhythmia, and in those with abnormal vital signs.
== Pharmacokinetic/pharmacodynamic (PK/PD) properties == Tedizolid tablets have an oral bioavailability of >90%. Tedizolid has higher binding to plasma proteins (80%), longer half-life, and a larger volume of distribution compared to linezolid. It is primarily metabolized by the liver as an inactive sulphate conjugate (phase II reaction), with no metabolism by cytochrome P-450 enzymes. Less than 20% of the drug is excreted unchanged in the urine. Tedizolid bactericidal activity on vancomycin-resistant Enterococcus (VRE) and methicillin-resistant Staphylococcus aureus (MRSA) is time dependent. Correlations are closest between fAUC24/MIC and the tedizolid PK/PD index against MRSA and VRE. To achieve 1
These fears of subversive Peruvians were also fueled by the widely publicized kidnapping, together with the collection of a ransom of 1,000,000 dollars, of the Bolivian businessman and politician Samuel Doria Medina; a fact that was carried out by Peruvians (also classified as subversives) members of the Tupac Amaru Revolutionary Movement (MRTA). All of which were events that generated a very bad reputation for Peruvians among Bolivian society, being incited by said prejudices and stereotypes by the morbidity of the press. Despite everything, Bolivian institutions report that, in the prison population of in that country, it is not a reality that the number of Peruvian prisoners is proportionally greater than the Bolivian citizens sentenced to prison. The Commission for Human Rights and Pacification of the Congress of the Republic of Peru has come to examine multiple cases of aggressions and mistreatment in Bolivia, against Peruvian citizens, including Congresswoman Susana Díaz, after a trip to Bolivia, verified the excesses committed against Peruvian groups, coming to denounce that there is an "anti-Peruvian phobia", especially in the Desaguadero.
Sources: en.wikipedia.org
=== Pharmacokinetics === Following a single topical application of 10 g nadifloxacin 1% cream to normal human back skin, the highest plasma concentration was determined to be 107 ng/mL with an elimination half-life of 19.4 hours. Approximately 0.09% of the administered dose was excreted in the urine over 48 hours post- dosing. The plasma concentration reached a steady state on Day 5 of repeated administration study when nadifloxacin 1% cream was applied at 5 g twice daily to normal healthy individuals for a period of 7 days. The plasma concentration reached a peak of 4.1 ng/ml at 8 hours post-final dosing with an elimination half-life of 23.2 hours. The urinary excretion rate reached 0.16% on Day 7.
Men: 13.8 to 18.0 g/dL (138 to 180 g/L, or 8.56 to 11.17 mmol/L) Women: 12.1 to 15.1 g/dL (121 to 151 g/L, or 7.51 to 9.37 mmol/L) Children: 11 to 16 g/dL (110 to 160 g/L, or 6.83 to 9.93 mmol/L) Pregnant women: 11 to 14 g/dL (110 to 140 g/L, or 6.83 to 8.69 mmol/L) (9.5 to 15 usual value during pregnancy) Normal values of hemoglobin in the 1st and 3rd trimesters of pregnant women must be at least 11 g/dL and at least 10.5 g/dL during the 2nd trimester. Dehydration or hyperhydration can greatly influence measured hemoglobin levels. Albumin can indicate hydration status. If the concentration is below normal, this is called anemia. Anemias are classified by the size of red blood cells, the cells that contain hemoglobin in vertebrates. The anemia is called "microcytic" if red cells are small, "macrocytic" if they are large, and "normocytic" otherwise. Hematocrit, the proportion of blood volume occupied by red blood cells, is typically about three times the hemoglobin concentration measured in g/dL. For example, if the hemoglobin is measured at 17 g/dL, that compares with a hematocrit of 51%. Laboratory hemoglobin test methods require a blood sample (arterial, venous, or capillary) and analysis on hematology analyzer and CO-oximeter. Additionally, a new noninvasive hemoglobin (SpHb) test method called Pulse CO-Oximetry is also available with comparable accuracy to invasive methods. Concentrations of oxy- and deoxyhemoglobin can be measured continuously, regionally and noninvasively using NIRS. NIRS can be used both on the head and on muscles.
Ossification (also called osteogenesis or bone mineralization) in bone remodeling is the process of laying down new bone material by cells named osteoblasts. It is synonymous with bone tissue formation. There are two processes resulting in the formation of normal, healthy bone tissue: Intramembranous ossification is the direct laying down of bone into the primitive connective tissue (mesenchyme), while endochondral ossification, also known as intracartilaginous ossification, involves cartilage as a precursor. In fracture healing, endochondral osteogenesis is the most commonly occurring process, for example in fractures of long bones treated by plaster of Paris, whereas fractures treated by open reduction and internal fixation with metal plates, screws, pins, rods and nails may heal by intramembranous osteogenesis. Heterotopic ossification is a process resulting in the formation of bone tissue that is often atypical, at an extraskeletal location. Calcification is often confused with ossification. Calcification is synonymous with the formation of calcium-based salts and crystals within cells and tissue. It is a process that occurs during ossification, but not necessarily vice versa. The exact mechanisms by which bone development is triggered remains unclear, but growth factors and cytokines appear to play a role.
Sources: en.wikipedia.org
This treatment uses vacuum to remove excess fluid and cellular waste that usually prolongs the inflammatory phase of wound healing. Despite a straightforward mechanism of action, the results of negative pressure wound therapy studies have been inconsistent. Research needs to be carried out to optimize the parameters of pressure intensity, treatment intervals, and exact timing to start negative pressure therapy in the course of chronic wound healing. There is low-certainty evidence that negative pressure wound therapy would improve wound healing in diabetic foot ulcers.
Oveporexton, sold under the brand name Orzeyful, is a medication used for the treatment of narcolepsy type 1. It is taken by mouth. The most common side effects include insomnia, increased urinary frequency, urgency to urinate, and increased saliva production. Oveporexton is an orexin OX2 receptor agonist. Oveporexton was approved for medical use in China in July 2026, and in the United States in August 2026. It is recommended for scheduling under the Controlled Substances Act and will be lawful to market in the US following the scheduling decision issued by the Drug Enforcement Administration.
== Diagnosis == Diagnosis typically occurs in the first few years of life and should be confirmed with a review of symptoms as well as genetic testing with targeted panels that include the ALMS1 gene as well as other ciliopathies, retinal diseases, cardiomyopathy, and obesity. Typically, the first symptoms to be observed are nystagmus, photophobia, impaired vision, and/or infantile cardiomyopathy within the first two years of life. Obesity and/or sensorineural hearing loss are often next and should be followed by genetic/molecular testing to try and identify two pathogenic variants of ALMS1 to confirm or deny the presence of the disease. However, the rarity of the disease, variability of symptoms, and lack of experts can make diagnosis very difficult. Additionally, since it can be difficult to identify both biallelic pathogenic variants in the ALMS1 gene, there is existing diagnostic criteria as shown below.
=== Structure === Tetrahymanol is a pentacyclic triterpenoid molecule. The triterpenoids are a class of molecules found in both bacteria and eukaryotes, which largely make hopanols and sterols, respectively. The structures of these three classes of molecules are shown below. Cholesterol and diploptene are used as model sterol and hopanol structures, respectively. While diploptene and tetrahymanol broadly have similar structures, the fifth ring on tetrahymanol is a cyclohexane rather than a cyclopentane. All three of these molecular classes have structures that lend themselves to membrane rigidity and other, still unknown, physiological functions. The similarity of tetrahymanol to the other classes of triterpenoid molecules allows it to substitute for hopanols and sterols in cell membranes. The tetrahymanol structure can have multiple stereoisomers. Its chiral methyl and hydrogen substituents can switch enantiomers during diagenesis, giving the molecule different properties with each isomer. When gammacerane, the diagenetic product of tetrahymanol, is analyzed, its isomers can be separated and provide information about the origin and thermal maturity of the sample.
Sources: en.wikipedia.org
不是。Semax 是完全人工合成的七肽，自然界中没有对应的已知肽段。它的设计灵感来自促肾上腺皮质激素片段 ACTH(4-10)，但序列经过了替换和延长。
Semax 被描述为 ACTH(4-10) 的结构类似物，两者共享部分序列特征。它保留了该片段的部分神经相关活性方向，但去除了完整片段带来的激素释放效应。二者并非同一物质，也不能互相替代。
加入的 Pro-Gly-Pro 三肽被普遍认为能提升分子对蛋白水解酶的稳定性。这种设计让短肽在体内维持时间更长。具体延长的程度以及不同组织中是否一致，文献中仍存在不同报告。
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.