The short version of single-use aliquot fits in a sentence. The long version — which is the one that helps — is below.
Reviewed 2026-06-28. Anything still debated is marked as such rather than presented as settled.
Semax is normally supplied as a lyophilized powder, and that form is the most stable. Suppliers commonly recommend storage at -20 °C in a desiccated container protected from light, with short-term handling at room temperature limited to weighing and transfer. Powder that has absorbed moisture degrades faster, so vials should be warmed to ambient temperature before opening to prevent condensation on the contents. Hygroscopic behavior is typical of short hydrophilic peptides, and humidity control matters more than temperature alone for long-term retention.
Once dissolved, the peptide is considerably less stable than the solid. Aqueous solutions are usually prepared at neutral to slightly acidic pH, filtered, and divided into single-use aliquots before freezing. Repeated freeze-thaw cycles are a common cause of avoidable loss and are best prevented by never refreezing a thawed aliquot. Adsorption to plastic and glass surfaces can lower the measured concentration of dilute solutions, particularly below roughly 0.1 mg/mL. Buffer choice, salt content, and container material all influence how much peptide remains detectable after storage.
Identity and purity are established with standard peptide methods. Reversed-phase HPLC with ultraviolet detection near 214 nm resolves the parent peak from deletion and truncation byproducts, and reports typically quote a main-peak percentage. Mass spectrometry by electrospray or MALDI-TOF confirms the expected molecular mass, while amino acid analysis or peptide mapping can verify composition when the sequence itself is in question. A certificate of analysis that pairs a chromatogram with a mass spectrum is more informative than a purity figure alone. Counter-ion content and residual solvents are separate specifications and are frequently omitted.
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.
| Property | Value | Notes |
|---|---|---|
| Solid storage temperature | -20 °C or below | Desiccated and protected from light |
| Solution storage temperature | -80 °C as single-use aliquots | Avoid repeated freeze-thaw cycles |
| Purity assessment method | RP-HPLC, around 214 nm | Reported as main-peak area percent |
| Identity confirmation method | ESI-MS or MALDI-TOF | Measured mass compared with calculated mass |
| Common synonyms | ACTH(4-10) analog; Met-Glu-His-Phe-Pro-Gly-Pro | Also written as Semaxum in some sources |
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。
Material sold for laboratory use varies widely in stated purity and documentation. A certificate of analysis should list the analytical method, the column and detector used, and the observed purity value. Independent verification by an outside laboratory is the practical way to confirm identity when documentation is absent or internally inconsistent. Regulatory status differs by country, and a product legal in one jurisdiction may be unapproved or controlled in another.
Identity and purity of semax are established with reversed-phase high-performance liquid chromatography coupled to ultraviolet detection, usually at 214 nanometres. Mass spectrometry, most often electrospray ionisation in positive mode, confirms the molecular mass and reveals truncated sequences. Amino acid analysis and peptide mapping after enzymatic digestion provide additional structural confirmation. Laboratories typically report purity as the percentage area of the main peak, a figure that does not capture isomeric or oxidised variants unless the method resolves them.
The peptide is prone to several degradation pathways. Oxidation of the methionine residue produces a sulfoxide that elutes close to the parent peak in many chromatographic systems. Hydrolysis of peptide bonds and deamidation of susceptible residues in related sequences also reduce purity over time. Lyophilised material kept dry at minus twenty degrees Celsius and shielded from light is the most stable form commonly described in laboratory 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.
Solid material is normally kept at minus 20 degrees Celsius in a sealed, desiccated container. Reconstituted solutions are less stable and are usually divided into single-use aliquots before freezing. Repeated freeze-thaw cycles are avoided because they promote aggregation and loss of activity. Light exposure is minimized by using amber glassware or foil wrapping. Published stability data for this peptide are sparse, so recommended storage conditions rest mainly on general practice for short synthetic peptides rather than on dedicated study.
== References == Hansard Indexes for 1993–2000, "Legislature of Western Australia" "No.32 (Special)". Western Australia Government Gazette. 16 February 1993. p. 1993:1287–1289. "No.116 (Special)". Western Australia Government Gazette. 25 August 1993. p. 1993:4599. "No.8 (Special)". Western Australia Government Gazette. 25 January 1994. p. 1994:278–279. "No.18 (Special)". Western Australia Government Gazette. 10 February 1995. p. 1995:477–478. "No.176 (Special)". Western Australia Government Gazette. 21 December 1995. p. 1995:6163–6164. "No.5 (Special)". Western Australia Government Gazette. 9 January 1997. p. 1997:99–100. Phillips, Harry; Black, David (June 1996). "Australian Political Chronicle: July–December 1995". Australian Journal of Politics and History. 42 (2): 271. ISSN 0004-9522.
== Research contributions == Esimone pioneered research in the use of recombinant viral vectors as surrogates for high-throughput antiviral screening studies, as well as on the use of indigenous medicinal plants as immunomodulators, vaccine adjuvants, and anti-infectives. The vector-based antiviral screening technique developed by Esimone between 2003 and 2005 in Germany significantly revolutionized high-throughput screening for anti-HIV compounds worldwide. In addition to this work, his research led to the discovery of new antimicrobial compounds—including antibacterial, antifungal, and antiviral agents—derived from endophytes, lichens, ferns, herbs, and spices. Esimone was instrumental in the isolation and characterization of resistance genes from clinical settings, abattoirs, and poultry, with a particular focus on extended-spectrum beta-lactamases (ESBLs) and metallo-beta-lactamases (MBLs) identified in the southeastern regions of Nigeria. His team became the first to demonstrate the presence of ESBL-producing bacteria harboring the CTXM-15 gene, which confers resistance to third-generation cephalosporins in Nigeria. Additionally, they were the first to identify MBL-producing bacteria containing the blaIMP-1 and blaVIM-1 genes within poultry and abattoirs in southeastern Nigeria. They also reported the increasing frequency of MBL-producing Klebsiella, Pseudomonas, and Escherichia species in the country.
Chemical detection is integrated into the device to ensure careful monitoring of reactions, NMR spectroscopy, microscopy, electrochemical detection, and chemiluminescent detection are used. Often, measurements are taken at different points along the microfluidic device to monitor the progress of the reaction. Increased rate of reactions using microdroplets is seen in the aldol reaction of silyl enol ethers and aldehydes. Using a droplet-based microfluidic device, reaction times were shortened to twenty minutes versus the twenty-four hours required for a batch process. Other experimenters were able to show a high selectivity of cis-stilbene to the thermodynamically favored trans-stilbene compared to the batch reaction, showing the high degree of control afforded by microreactor droplets. This stereocontrol is beneficial to the pharmaceutical industry. For instance, L-Methotrexate, a drug used in chemotherapy, is more readily absorbed than the D isomer.
Sources: en.wikipedia.org
=== Spain === All Spanish medical degree holders need to pass a competitive national exam (named 'MIR') in order to access the specialty training program. This exam gives them the opportunity to choose both the specialty and the hospital where they will train, among the hospitals in the Spanish Healthcare Hospital Network. Currently, medical specialties last from 4 to 5 years. There are plans to change the training program system to one similar to the UK's. There have been some talks between Ministry of Health, the Medical College of Physicians and the Medical Student Association but it is not clear how this change process is going to be.
In addition to his academic work, Baran also holds many accolades in industry as a scientific entrepreneur, company co-founder, consultant and scientific advisor. He co-founded his first company Sirenas Marine Discovery in 2012 alongside Eduardo Esquenazi and Jake Beverage —a company that is focused on marine-inspired small molecules and pre-clinical leads for cancer, HIV, and infectious diseases. In 2016, he joined forces with fellow Scripps colleagues, Benjamin F. Cravatt and Jin-Quan Yu to co-found Vividion Therapeutics with the goal of identifying small molecules that bind currently undrugged targets via a covalent-first chemoproteomics approach. Vividion was sold to Bayer in 2021 for up to $2 billion ($1.5 billion with an additional $500 million in milestone payments). In the same year, Baran founded Elsie Biotechnologies, an antisense oligonucleotide (ASO)-based company with the goal of discovering therapeutic agents that can achieve desirable medicinal effects not attainable with existing drugs by modulating gene expression of DNA or RNA. Elsie Biotechnologies was sold to GlaxoSmithKline (GSK) in 2024 for $50 million. Baran also co-founded and is on the scientific advisory team of Galileo Biosystems, a preclinical stage biopharmaceutical company focused on developing therapeutic agents for inflammatory and autoimmune diseases.
=== Template synthesis === The template synthesis method uses a nanoporous membrane template composed of cylindrical pores of uniform diameter to make fibrils (solid nanofiber) and tubules (hollow nanofiber). This method can be used to prepare fibrils and tubules of many types of materials, including metals, semiconductors and electronically conductive polymers. The uniform pores allow for control of the dimensions of the fibers so nanofibers with very small diameters can be produced through this method. However, a drawback of this method is that it cannot make continuous nanofibers one at a time.
=== Analgesic === Data from clinical trials have indicated that SNRIs might have pain-relieving properties. Although the perception and transmission of pain stimuli in the central nervous system have not been fully elucidated, extensive data support the roles of serotonin and norepinephrine in pain modulation. Findings from clinical trials in humans have shown that these antidepressants can help to reduce pain and functional impairment in central and neuropathic pain conditions. This property of SNRIs might be used to reduce doses of other pain relieving medication and lower the frequency of safety, limited efficacy, and tolerability issues. Clinical research data has shown that in patients with GAD, duloxetine is significantly more effective than placebo in reducing pain-related symptoms of GAD, after short-term and long-term treatment. However, findings suggested that such symptoms of physical pain recur in relapse situations, which indicate a need for ongoing treatment in patients with GAD and concurrent painful physical symptoms.
Sources: en.wikipedia.org
drugs that also prolong the QT interval because of potential problems with the heart rhythm ergot alkaloids statins triazolam and oral midazolam sulfonamides with a potential to cause hypoglycaemia (low blood sugar)
=== Breastfeeding in humanitarian emergencies === During humanitarian crises, conflicts, forced displacement, and natural disasters, mothers and caregivers face additional difficulties in maintaining adequate breastfeeding practices. They may experience physical and mental exhaustion, lack safe and private spaces for on-demand breastfeeding, and have limited social support. In many of these situations, unsolicited donations of breast milk substitutes may be distributed through well-intentioned but poorly informed solidarity initiatives. Relying on these products often interrupts breast milk production and creates dependence on formula milk, whose use carries critical health risks in settings where clean water and hygiene materials are not fully accessible. Following a key meeting hosted by the International Baby Food Action Network (IBFAN) in 1995, the Infant Feeding in Emergencies (IFE) Core Group was established in 1999 to address policy guidance and capacity-building on infant and young child feeding in emergencies. Over the years, and in collaboration with many other humanitarian organisations, the IFE Core Group has issued key recommendations aimed at monitoring and controlling unsolicited donations of breast milk substitutes, protecting early initiation of breastfeeding, providing food or financial assistance to caregivers, safeguarding infants who depend exclusively on formula milk, establishing and maintaining community support spaces for infant and young child feeding, and fostering inter-sectoral coordination to promote a positive environment for breastfeeding.
== Global occurrence and sources == PFOA contaminates every continent. Two of the most common types of PFAS (more precisely, PFOS and PFOA) were phased out of production in the United States (US) in 2002 and 2015 respectively, but are still present in some imported products. PFOA and PFOS are found in every American person's blood stream in the parts per billion range, though those concentrations have decreased by 70% for PFOA and 84% for PFOS between 1999 and 2014, which coincides with the end of the production and phase out of PFOA and PFOS in the US. PFOA has been detected in the central Pacific Ocean at low parts per quadrillion ranges, and at low parts per trillion (ppt) levels in coastal waters. Due to the surfactant nature of PFOA, it has been found to concentrate in the top layers of ocean water. PFOA is detected widely in surface waters, and is present in numerous mammals, fish, and bird species. PFOA is in the blood or vital organs of Atlantic salmon, swordfish, striped mullet, gray seals, common cormorants, Alaskan polar bears, brown pelicans, sea turtles, sea eagles, Midwestern bald eagles, California sea lions and Laysan albatrosses on Sand Island, a wildlife refuge on Midway Atoll, in the middle of the North Pacific Ocean, about halfway between North America and Asia. Because PFAS are ubiquitous in households, consumer products, food, and the environment generally, some trace levels reflecting this ubiquitous broad use of these compounds will make their way into the wastewater and solid waste streams.
In neurons that use DA as the transmitter, the decarboxylation of L-DOPA to dopamine is the final step in formation of the transmitter; however, in those neurons using norepinephrine (noradrenaline) or epinephrine (adrenaline) as transmitters, the enzyme dopamine β-hydroxylase (DBH), which converts dopamine to yield norepinephrine, is also present. In still other neurons in which epinephrine is the transmitter, a third enzyme phenylethanolamine N-methyltransferase (PNMT) converts norepinephrine into epinephrine. Thus, a cell that uses epinephrine as its transmitter contains four enzymes (TH, AADC, DBH, and PNMT), whereas norepinephrine neurons contain only three enzymes (lacking PNMT) and dopamine cells only two (TH and AADC).
q = 1/2ρv2 is dynamic pressure, h = z + p/ρg is the piezometric head or hydraulic head (the sum of the elevation z and the pressure head) and p0 = p + q is the stagnation pressure (the sum of the static pressure p and dynamic pressure q). The constant in the Bernoulli equation can be normalized. A common approach is in terms of total head or energy head H:
Sources: en.wikipedia.org
Each freeze-thaw cycle can degrade a fraction of the peptide and promote aggregation. Dividing a stock solution into single-use volumes removes repeated cycling as a variable. It also limits the time a thawed solution spends at room temperature.
A high main-peak percentage says little about identity, counter-ion content, or residual solvents. It also does not distinguish an isomer or a closely eluting analog. Mass confirmation and the accompanying documentation cover those gaps.
Salt form changes mass, solubility, and hygroscopicity, and acetate and trifluoroacetate salts behave differently in solution. Storage guidance still centers on -20 °C for powder and lower temperatures for solutions. The certificate should state which salt is present.
Dry powder is normally held at -20 °C or lower, away from light and moisture. Sealed vials can also be kept at 2-8 °C for shorter intervals. Warming to room temperature before opening prevents condensation.