This is a working overview of nasal formulation, written for readers who want more than a one-paragraph summary but less than a textbook.
Reviewed 2025-12-12. Anything still debated is marked as such rather than presented as settled.
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.
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.
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.
| Property | Value | Notes |
|---|---|---|
| Molecular formula | C37H51N9O10S | Seven-residue peptide |
| Molecular mass | 813.9 Da | Monoisotopic value |
| Appearance | White to off-white powder | Lyophilized form |
| Solubility | Freely soluble in water | Also soluble in saline and polar solvents |
| Storage (dry) | -20 °C or lower | Desiccated, protected from light |
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.
Published studies are dominated by animal models of stroke, ischemia, and cognitive impairment, with a smaller number of human trials conducted in Russia. Many of the human reports are small, single-center, and published in Russian-language journals, which limits independent scrutiny. Outcome measures vary between studies and often rely on clinician-rated scales rather than objective biomarkers. Systematic reviews have noted the methodological weaknesses and called for larger, preregistered trials before firm conclusions can be drawn.
Claims about enhanced focus, memory, or mood in healthy people rest mostly on anecdotal reports and community discussion rather than on controlled data. It remains unclear whether any cognitive benefit observed in patients recovering from brain injury would extend to uninjured users. Dose-response relationships, long-term safety, and interactions with other drugs are not well characterized in the peer-reviewed literature. Questions about optimal route of administration and treatment duration likewise remain open.
Laboratory work points toward modulation of neurotrophic signaling, particularly expression of brain-derived neurotrophic factor and nerve growth factor in hippocampal tissue. Studies also describe effects on monoamine turnover, inflammatory mediators, and oxidative markers. These observations come mainly from animal models and cultured cells, so the causal chain in humans is not firmly established. Whether the reported molecular changes translate into measurable clinical benefit is an open question. Reviews generally present the mechanism as plausible rather than demonstrated.
Clinical evidence consists largely of small trials with modest sample sizes, often without independent replication. Reported endpoints include cognitive scores, recovery after stroke, and visual function, but study designs vary widely and few trials meet contemporary reporting standards. Systematic reviewers have noted a high risk of bias in several of these reports. No large multicenter trial conducted outside Russia has been published. The compound is therefore best described as investigational in most jurisdictions, with its clinical role still unresolved.
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。
纯度评估以反相高效液相色谱为主，通过主峰面积百分比给出粗略结果，再配合电喷雾质谱核对分子量。氨基酸分析可验证组成比例，手性色谱或毛细管电泳用于检查残基构型。常见杂质包括缺失序列的短肽、氧化产物与二聚体。由于多数市售品不附带完整检验报告，独立第三方检测常被用来核实标称值。
== Safety and regulation == α-Arbutin is generally considered safe for topical application in cosmetic products. However, its usage concentrations in the European Union (EU) are restricted by the European Commission Scientific Committee on Consumer Safety to 2% in facial creams and 0.5% in body lotions.
[18F]Fluorodeoxyglucose (INN), or fluorodeoxyglucose F 18 (USAN and USP), also commonly called fluorodeoxyglucose and abbreviated [18F]FDG, 2-[18F]FDG or FDG, is a radiopharmaceutical, specifically a radiotracer, used in the medical imaging modality positron emission tomography (PET). Chemically, it is 2-deoxy-2-[18F]fluoro-D-glucose, a glucose analog, with the positron-emitting radionuclide fluorine-18 substituted for the normal hydroxyl group at the C-2 position in the glucose molecule. The uptake of [18F]FDG by tissues is a marker for the tissue uptake of glucose, which in turn is closely correlated with certain types of tissue metabolism. After [18F]FDG is injected into a patient, a PET scanner can form two-dimensional or three-dimensional images of the distribution of [18F]FDG within the body. Since its development in 1976, [18F]FDG has had a profound influence on research in the neurosciences. The subsequent discovery in 1980 that [18F]FDG accumulates in tumors underpins the evolution of PET as a major clinical tool in cancer diagnosis. [18F]FDG is now the standard radiotracer used for PET neuroimaging and cancer patient management. The images can be assessed by a nuclear medicine physician or radiologist to provide diagnoses of various medical conditions.
== Chemistry == Like all ergopeptides, bromocriptine is a cyclol; two peptide groups of its tripeptide moiety are crosslinked, forming the >N-C(OH)< juncture between the two rings with the amide functionality. Bromocriptine is a semisynthetic derivative of a natural ergot alkaloid, ergocryptine (a derivative of lysergic acid), which is synthesized by bromination of ergocryptine using N-bromosuccinimide.
=== Insects === Order Blattodea Blattella germanica, German cockroach (2018) Periplaneta americana, American cockroach (2018) Zootermopsis nevadensis, a dampwood termite (2014 Cryptotermes secundus, a drywood termite(2018) Macrotermes natalensis, a higher termite (2014 Order Coleoptera Dendroctonus ponderosae Hopkins, beetle (mountain pine beetle) (2013) Aquatica lateralis, Japanese aquatic firefly "Heike-botaru" (firefly) (2018) Photinus pyralis, Big Dipper firefly (2018) Protaetia brevitarsis, White-spotted flower chafer (2019) Tribolium castaneum Strain:GA-2, beetle (red flour beetle) (2008) Allomyrina dichotoma, Japanese rhinoceros beetle (2022) Pachyrhynchus sulphureomaculatus, Easter Egg Weevil (2021) Order Collembola Family Isotomidae Desoria tigrina, (2021) Family Sminthurididae Sminthurides aquaticus, (2021) Order Diptera Family Calliphoridae Aldrichina grahami, Forensic blowfly (2020) Family Chironomidae Dasypogon diadema, Hunting Robber fly (2019) Parochlus steinend, Antarctic winged midge (2017) Proctacanthus coquilletti, Assassin fly (2017) Family Culicidae (mosquitoes) Aedes aegypti Strain:LVPib12, mosquito (vector of dengue fever, etc.) (2007) Aedes albopictus (2015) Anopheles darlingi Anopheles gambiae Strain: PEST, mosquito (vector of malaria) (2002) Anopheles gambiae Strain: M, mosquito (vector of malaria) (2010) Anopheles gambiae Strain: S, mosquito (vector of malaria) (2010) Anopheles sinensis, mosquito (vector of vivax malaria, lymphatic filariasis and Setaria infections), (2014) Anopheles stephensii Anopheles arabiensis (2015) Anopheles quadriannulatus (2015) Anopheles merus (2015) Anopheles melas (2015) Anopheles christyi (2015) Anopheles epiroticus (2015) Anopheles maculatus (2015) Anopheles culicifacies (2015) Anopheles minimus (2015) Anopheles funestus (2015, 2019) Anopheles dirus (2015) Anopheles farauti (2015) Anopheles atroparvus (2015) Anopheles sinensis (2015) Anopheles albimanus (2015) Culex quinquefasciatus, mosquito (vector of West Nile virus, filariasis etc.) (2010) Family Drosophilidae (fruit flies) Drosophila albomicans, fruit fly (2012) Drosophila ananassae, fruit fly (2007) Drosophila biarmipes, fruit fly (2011) Drosophila bipectinata, fruit fly (2011) Drosophila erecta, fruit fly (2007) Drosophila elegans, fruit fly (2011) Drosophila eugracilis, fruit fly (2011) Drosophila ficusphila, fruit fly (2011) Drosophila grimshawi, fruit fly (2007) Drosophila kikkawai, fruit fly (2011) Drosophila melanogaster, fruit fly (model organism) (2000) Drosophila mojavensis, fruit fly (2007) Drosophila neotestacea, fruit fly (transcriptome 2014) Drosophila persimilis, fruit fly (2007) Drosophila pseudoobscura, fruit fly (2005) Drosophila rhopaloa, fruit fly (2011) Drosophila santomea, fruit fly () Drosophila sechellia, fruit fly (2007) Drosophila simulans, fruit fly (2007) Drosophila takahashi, fruit fly (2011) Drosophila virilis, fruit fly (2007) Drosophila willistoni, fruit fly (2007) Drosophila yakuba, fruit fly (2007) Family Phoridae Megaselia abdita, scuttle fly (transcriptome 2013) Family Psychodidae (drain flies) Clogmia albipunctata, moth midge (transcriptome 2013) Family Sarcophagidae (flesh flies) Sarcophaga Bullata, Flesh fly (2019) Family Syrphidae (hoverflies) Episyrphus balteatus, hoverfly (transcriptome 2011) Order Hemiptera Acyrthosiphon pisum, aphid (pea aphid) (2010) Ericerus pela, Chinese wax scale insect (2019) Laodelphax striatellus, small brown planthopper (2017) Lycorma delicatula, spotted lanternfly (2019) Rhodnius prolixus, kissing-bug (2015) Rhopalosiphum maidis, Corn leaf aphid (2019) Sitobion miscanthi, Indian grain aphid (2019) Triatoma rubrofasciata, assassin bug (2019) Order Hymenoptera Acromyrmex echinatior colony Ae372, ant (Panamanian leafcutter) (2011) Apis mellifera, bee (honey bee), (model for eusocial behavior) (2006) Atta cephalotes, ant (leaf-cutter ant) (2011) Camponotus floridanus, ant (2010) Cerapachys biroi, ant (clonal raider ant)(2014) Euglossa dilemma, Green orchid bee (2017) Harpegnathos saltator, ant (2010) Lasius niger, ant (black garden ant)(2017) Linepithema humile, ant (Argentine ant) (2011) Nasonia giraulti, wasp (parasitoid wasp) (2010) Nasonia longicornis, wasp (parasitoid wasp) (2010) Nasonia vitripennis, wasp (parasitoid wasp; model organism) (2010) Netelia fuscicornis, wasp (parasitoid wasp) (2024) Nomia Melanderi, Alkali bee (2019) Pogonomyrmex barbatus, ant (red harvester ant) (2011) Solenopsis invicta, ant (fire ant) (2011) Order Lepidoptera Abrostola tripartita Hufnagel, Spectacle (2021) Achalarus lyciades, Hoary Edge Skipper (2017) Ahamus jianchuanensis, Jianchuan ghost moth (2024) Antharaea yamamai, Japanese oak silk moth (2019) Arctia plantaginis, Wood tiger moth (2020) Bicyclus anynana, squinting bush brown (2017) Bombyx mori Strain:p50T, moth (domestic silk worm) (2004) Calycopis cecrops, Red-Banded Groundstreak (2016) Calycopis isobeon, Dusky-Blue Groundstreak (2016) Coenonympha arcania, Pearly Heath (2024) Cydia pomonella, codling moth (2019) Danaus plexippus, monarch butterfly) (2011) Erebia cassioides, Common Brassy Ringlet (2025) Heliconius melpomene, butterfly (2012) Keiferia lycopersicella, Tomato pinworm (2024) Melitaea cinxia, Glanville fritillary butterfly (2014) Megathymus ursus violae, bear giant skipper butterfly (2018) Morpho helenor, Common blue morpho (2023) Morpho achilles, Blue-banded morpho (2023) Morpho deidamia (2023) Papilio bianor, Chinese peacock butterfly (2019) Phthorimaea absoluta, Tomato leafminer (2024) Pieris rapae, small cabbage white butterfly (2016) Plodia interpunctella, Indianmeal moth (2022) Plutella xylostella, moth (diamondback moth) (2013) Scrobipalpa atriplicella, Goosefoot groundling moth (2024) Spodoptera frugiperda, Fall armyworm (2017) Thitarodes armoricanus, Himalaya ghost moth (2024) Thitarodes xiaojinensis, Xiaojin ghost moth (2024) Troides aeacus, Golden birdwing (2024) Eudocima phalonia, fruit-piercing moth (2017) Order Orthoptera Locusta migratoria, migratory locust (2014) Schistocerca gregaria, desert locust (2020) Gryllus bimaculatus, two-spotted cricket (2021) Order Phthiraptera Pediculus humanus, louse (sucking louse; parasite) (2010) Menopon gallinae, Poutlry shaft louse (2024) Psocoptera Liposcelis brunnea, booklouse (2022) Order Raphidioptera Venustoraphidia nigricollis, black-necked snakefly (2023) Order Trichoptera Eubasilissa regina, purple caddisfly (2022,) Stenopsyche tienmushanensisi, Caddisfly (2018) Order Mantodea Tenodera sinensis, chinese praying mantis (2023)
Sources: en.wikipedia.org
Dipeptides are white solids. Many are far more water-soluble than the parent amino acids. For example, the dipeptide Ala-Gln has the solubility of 586 g/L more than 10x the solubility of Gln (35 g/L). Dipeptides also can exhibit different stabilities, e.g. with respect to hydrolysis. Gln does not withstand sterilization procedures, whereas this dipeptide does. Because dipeptides are prone to hydrolysis, the high solubility is exploited in infusions, i.e. to provide nutrition.
=== Forms === As of 2010, methylnaltrexone is supplied as an injection in trays containing seven one-dose vials containing 0.6 mL of solution. Each tray also contains seven 12 mm (0.47 in) 1 mL 27 gauge needles with retractable tips, and alcohol wipes for home use. A single vial can treat someone who weighs as much as 115 kilograms (254 lb). For hospital use, vials are available separately. It is also now available in 150 mg oral tablets, taken 3 to 5 times daily.
=== Infections and infestations === Apple scab, an apple tree (genus Malus) fungal disease caused by Venturia inaequalis Black scab, a potato fungal disease caused by Synchytrium endobioticum Common scab, a plant bacterial disease caused by Streptomyces species Fusarium head blight, a fungal disease of plants, e.g., grain crops (especially wheat and oats), golf course grass, caused by the several species of Fusarium Pear scab, a pear fungal disease caused by Venturia pirina or Fusicladium pyrorum Poinsettia scab, a spot anthracnose disease caused by Sphaceloma poinsettiae Powdery scab, a disease of the skin of potatoes caused by the protozoa Spongospora subterranea Sheep scab, a skin disease of sheep caused by the mite Psoroptes ovis
29 January Conservative Party Chairman Nadhim Zahawi is sacked by Rishi Sunak over "a serious breach of the Ministerial Code" relating to the investigation into his tax affairs, conducted on 23 January. The Scottish Prison Service pauses the movement of all transgender prisoners while it carries out an "urgent review" into the transgender cases held in its custody. 30 January William Shawcross, the commissioner for public appointments, steps back from the planned investigation into how Richard Sharp got the job as BBC chairman because of previous contact between them. Another investigator will be appointed to take on the inquiry. Members of the Fire Brigades Union vote to take strike action over pay.
=== Limitations === Proteolysis does not always yield a set of readily analyzable peptides covering the entire sequence of POI. The fragmentation of peptides in the mass spectrometer often does not yield ions corresponding to cleavage at each peptide bond. Thus, the deduced sequence for each peptide is not necessarily complete. The standard methods of fragmentation do not distinguish between leucine and isoleucine residues since they are isomeric. Because the Edman degradation proceeds from the N-terminus of the protein, it will not work if the N-terminus has been chemically modified (e.g. by acetylation or formation of Pyroglutamic acid). Edman degradation is generally not useful to determine the positions of disulfide bridges. It also requires peptide amounts of 1 picomole or above for discernible results, making it less sensitive than mass spectrometry.
Sources: en.wikipedia.org
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.
The extension was introduced to slow enzymatic breakdown of the peptide in biological systems. Natural ACTH fragments are degraded rapidly by peptidases. Adding the tripeptide was intended to extend the window during which the molecule remains intact.
Most published work consists of animal experiments conducted in a small number of laboratories. Human data are limited in number and size. Whether the observed effects translate into reliable clinical benefit is still unresolved.
Dry powder is usually kept at about -20 degrees Celsius for long-term storage and at 2 to 8 degrees Celsius for short working periods. Containers should stay sealed and protected from light and moisture to limit degradation.