nasal drops raises a handful of sensible questions. This page answers them in order, starting with the fundamentals and moving to applications.
Reviewed 2025-11-13. Anything still debated is marked as such rather than presented as settled.
Regulatory status varies sharply by country. Semax is registered for medical use in Russia, where it appears in formularies as a nasal solution, and it also holds registration in a small number of neighbouring states. It has no approval from the United States Food and Drug Administration or the European Medicines Agency, and it is not a scheduled controlled substance in most jurisdictions. Elsewhere it circulates mainly as laboratory material, so purity documentation comes from suppliers rather than from a national pharmacopoeia.
Semax is a synthetic peptide created in the Soviet Union during the early 1980s by researchers working in Moscow. It was built from the short adrenocorticotropic hormone fragment known as ACTH(4-10), and the chain was then extended with three additional amino acids. The resulting molecule was named semax and entered clinical use in Russia in 1994. It is generally described as a nootropic and neuroprotective agent rather than as a hormone analogue.
Verification of a supplied batch generally combines a certificate of analysis with independent testing, because certificates are self-reported documents. A typical package includes a chromatographic trace, a mass spectrum, and a stated water or counter-ion content. Batch-to-batch consistency matters more than a single purity figure when results are compared across experiments. No single mandatory standard governs research-grade peptide release, so laboratories are expected to define their own acceptance criteria. Residual trifluoroacetate from purification is a frequently overlooked counter-ion.
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 |
|---|---|---|
| Chemical class | Synthetic heptapeptide | Analogue of the ACTH(4-10) fragment |
| Amino acid sequence | Met-Glu-His-Phe-Pro-Gly-Pro | Single-letter form MEHFPGP |
| Molecular formula | C37H51N9O10S | Free peptide, nominal mass near 814 Da |
| First registration | 1994, Russia | Nasal formulation for neurological indications |
| Typical purity grade | 95% or higher by HPLC | Research material; higher grades used as reference standards |
The proposed mechanism centres on neurotrophic signalling rather than direct receptor activation. Semax is reported to increase expression of brain-derived neurotrophic factor and nerve growth factor in several brain regions, and to shift the balance between excitatory and inhibitory neurotransmitter systems. Interaction with melanocortin receptors has been suggested because of the parent ACTH fragment. Many of these findings come from rodent studies, and the extent to which they translate to human physiology remains an open question.
Scientific literature on semax is unevenly distributed. A substantial share of published work originates from a small number of laboratories in Russia, while independent replication elsewhere is limited. Human data consist mostly of small trials with short follow-up, and several reported outcomes rely on subjective rating scales. Questions about how much intact peptide reaches the central nervous system after nasal administration, and how long it persists there, are still unresolved. The compound is best described as an active research subject rather than a settled pharmacological agent.
Semax is a synthetic heptapeptide with the sequence Met-Glu-His-Phe-Pro-Gly-Pro. It was derived from the ACTH(4-10) fragment, a short segment of adrenocorticotropic hormone that lacks the hormonal activity associated with the full-length peptide. Researchers at the Institute of Molecular Genetics in Moscow developed the compound during the 1980s. It has been registered as a pharmaceutical product in Russia and several neighbouring countries, where it is supplied as a nasal solution, and it is also sold internationally as a research chemical.
Lyophilised powder is normally kept at -20 °C in a desiccated container, with some suppliers recommending -80 °C for long-term archival storage. Repeated freeze-thaw cycles are the most common cause of avoidable loss, so aliquoting before freezing reduces variability between working sessions. Dissolved peptide is far less stable than the dry solid and is usually prepared fresh or held briefly at 4 °C. Aqueous solutions support both hydrolysis of the backbone and oxidation of the N-terminal methionine, and these two routes dominate degradation under ordinary laboratory conditions.
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.
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.
In "Black Mesa Inbound", the player controls Gordon Freeman as he enters the facility on a monorail. After noticing the G-Man on a different train, Gordon departs and enters the Anomalous Materials Lab. He explores the area, donning his Hazardous Environment Suit, and then enters the test chamber. After the Anti-Mass Spectrometer power is turned up to 105%, the Resonance Cascade disaster occurs, and Freeman must escape the destroyed chamber. In "Unforeseen Consequences", Freeman returns to the Anomalous Materials Lab, fighting his way through the aliens that have started appearing from warps in space. He then makes his way through an office complex. In "We've Got Hostiles", Freeman encounters the Hazardous Environment Combat Unit (HECU), a special forces unit of the United States Marine Corps sent to cover up the disaster by killing all of the surviving Black Mesa personnel. He travels through a series of Cold War-era storage rooms to reach the surface. Escaping an Osprey helicopter, he goes back underground in a different location. In "Blast Pit", he must destroy an alien tentacle that has appeared from beneath a nuclear silo. After successfully destroying the tentacle with a rocket engine, in "Power Up", Freeman must kill a Gargantua alien by baiting it into a room with giant Tesla coils. He then navigates a series of underground rail tunnels in "On a Rail", culminating in the rocket launch of a satellite that can determine the scope of the disaster. In "Apprehension", Freeman fights through flooded rooms filled with aquatic aliens called Icthyosaurs.
Each intervention is evaluated simultaneously at all participating ITP sites using identical experimental protocols, animal husbandry practices, dosing regimens, and outcome measures, ensuring exceptional scientific rigor, reproducibility, and confidence in the results. Research conducted through the ITP has significantly advanced the field of geroscience by identifying interventions that reproducibly increase lifespan and improve measures of healthspan. Investigators evaluate a wide range of compounds and therapeutic strategies targeting key biological mechanisms of aging, including nutrient-sensing pathways, cellular senescence, mitochondrial function, proteostasis, inflammation, oxidative stress, autophagy, stem cell maintenance, and metabolic regulation. In addition to determining effects on longevity, studies assess functional outcomes such as physical performance, metabolic health, cardiovascular function, cognitive performance, cancer incidence, immune function, and age-related pathology. These comprehensive phenotypic assessments provide valuable insights into how interventions influence both lifespan and the quality of aging. The Barshop Institute's extensive aging research infrastructure substantially enhances the capabilities of the Interventions Testing Program.
Geologists consider her to be the "first woman geologist in this country (America)". 1893: American botanist Elizabeth Gertrude Britton became a charter member of the Botanical Society of America. 1894: American astronomer Margaretta Palmer became the first woman to earn a doctorate in astronomy. 1895: English physiologist Marion Bidder became the first woman to speak and present her own paper at a meeting of the Royal Society. 1896: Florence Bascom became the first woman to work for the United States Geological Survey. 1896: English mycologist and lichenologist Annie Lorrain Smith became a founding member of the British Mycological Society. She later served as president twice. 1896: Russian ophthalmologist Rosa Kerschbaumer-Putjata graduated from the University of Bern. She became the first female doctor permitted to practice in Austria due to a special permit granted by Emperor Franz Joseph I of Austria. She campaigned for women's right to study medicine in Austria. 1897: American cytologists and zoologists Katharine Foot and Ella Church Strobell started working as research partners. Together, they pioneered the practice of photographing microscopic research samples and invented a new technique for creating thin material samples in colder temperatures. 1897: American physicist Isabelle Stone became the first woman to receive a PhD in physics in the United States. She wrote her dissertation "On the Electrical Resistance of Thin Films" at the University of Chicago.
10 January – First Minister Humza Yousaf confirms those in Scotland convicted because of the Post Office scandal will be cleared following a similar announcement at Westminster for England and Wales, and that he will work with the UK government to bring this about. It is reported that David Page, the deputy chief officer at Police Scotland and the force's most senior member of civilian staff, has made a complaint against new Chief Constable Jo Farrell, doing so within weeks of her arrival. 11 January – First Minister Humza Yousaf confirms that the Scottish Government will "in essence replicate" the law in England and Wales banning unlicensed ownership of American XL bully dogs. Plans are announced for West Town, a £2bn 7,000 home development on land near Edinburgh Airport. 13 January – A 70-year-old woman is charged after a car ran into protesters at a pro-Palestine march in Edinburgh. 14 January – Ramsay El-Nakla, the brother-in-law of Humza Yousaf, has been charged by police in connection with drugs offences. 15 January – Robert O'Brien and Andrew Kelly are sentenced to life imprisonment with minimum terms of 22 and 18 years respectively for the 1996 murder of Caroline Glachan. James Stockan announces he will step down from the post of leader of Orkney Islands Council, as well as relinquishing his council seat, after six years in the role. 16 January – A yellow weather warning is in place for snow and ice for the whole of Scotland.
=== Pharmacokinetics === Metabolism of ciprofol occurs primarily in the liver through oxidation, glucuronidation, and sulfation, resulting in the formation of the inactive metabolite M4-glucuronide, which is excreted renally. It is not necessary to adjust the dose in people with mild or moderate renal impairment, or in those with mild or moderate hepatic impairment. In elderly people, a slightly lower dose (0.3 mg/kg) appears to be similar in efficacy to the higher doses administered to younger people but is associated with fewer adverse effects. Ciprofol has a short elimination half-life, generally between 2 and 4 hours. Owing to its rapid metabolism and high clearance, the drug does not tend to accumulate in the body, even during prolonged infusions.
Sources: en.wikipedia.org
== Availability == Availability of products containing P11-4 vary by country, with some products available only to dentists, and others available to the retail public. Medical device for caries treatment and enamel regeneration:
=== Myopathies with fiber size variation === Myopathies with varying fiber size, such as congenital fiber type disproportion, occurs when type 1 fibers, the slow twitch fibers involved in sustaining activity, are smaller than type 2 fibers, the fast twitch fibers involved in quick activity. Since smaller type 1 fibers is not associated with nemaline myopathy, the most common type of congenital myopathy, it has not been studied in as great detail as many of the others. However, the smaller type 1 fibers explains why patients typically can participate in activities for shorter periods of time, but struggle with extended activity.
In regard to companies, the Court of Justice held in R (Daily Mail and General Trust plc) v HM Treasury that member states could restrict a company moving its seat of business, without infringing TFEU article 49. This meant the Daily Mail newspaper's parent company could not evade tax by shifting its residence to the Netherlands without first settling its tax bills in the UK. The UK did not need to justify its action, as rules on company seats were not yet harmonised. By contrast, in Centros Ltd v Erhversus-og Selkabssyrelsen the Court of Justice found that a UK limited company operating in Denmark could not be required to comply with Denmark's minimum share capital rules. UK law only required £1 of capital to start a company, while Denmark's legislature took the view companies should only be started up if they had 200,000 Danish krone (around €27,000) to protect creditors if the company failed and went insolvent. The Court of Justice held that Denmark's minimum capital law infringed Centros Ltd's freedom of establishment and could not be justified, because a company in the UK could admittedly provide services in Denmark without being established there, and there were less restrictive means of achieving the aim of creditor protection. This approach was criticised as potentially opening the EU to unjustified regulatory competition, and a race to the bottom in legal standards, like the US state of Delaware, which is argued to attract companies with the worst standards of accountability, and unreasonably low corporate tax.
Theca cells are responsible for synthesizing androgens, providing signal transduction between granulosa cells and oocytes during development by the establishment of a vascular system, providing nutrients, and providing structure and support to the follicle as it matures. Theca cells are responsible for the production of androstenedione, which is supplied to the neighboring granulosa cells where it is converted into estrone (a weak estrogen) by the enzyme aromatase, and then further converted into estradiol (a strong estrogen) by the enzyme 17β-HSD1. FSH stimulates granulosa cells to synthesize aromatase and 17β-HSD, which is necessary for this process.
Sources: en.wikipedia.org
==== Scientific uses ==== The use of helium reduces the distorting effects of temperature variations in the space between lenses in some telescopes due to its extremely low index of refraction. This method is especially used in solar telescopes where a vacuum tight telescope tube would be too heavy. Helium is a commonly used carrier gas for gas chromatography. The age of rocks and minerals that contain uranium and thorium can be estimated by measuring the level of helium with a process known as helium dating. Helium at low temperatures is used in cryogenics and in certain cryogenic applications. As examples of applications, liquid helium is used to cool certain metals to the extremely low temperatures required for superconductivity, such as in superconducting magnets for magnetic resonance imaging. The Large Hadron Collider at CERN uses 96 metric tons of liquid helium to maintain the temperature at 1.9 K (−271.25 °C; −456.25 °F).
== Activity == Klebsazolicin is active against Gram-negative bacteria closely related to Klebsiella, such as Escherichia coli, Klebsiella pneumoniae, and Yersinia pseudotuberculosis. KLB inhibits protein synthesis on the prokaryotic ribosome by binding to and blocking peptide exit tunnel and thus preventing the passage of the nascent peptide. The activity of KlpE export pump encoded in KLB biosynthetic gene cluster confers self-resistance of the producing bacterium to the action of the antibiotic.
This follows an exchange in the House during PMQs when Starmer, answering a question from the leader of the opposition, Kemi Badenoch, said that "two of her predecessors had convictions for breaking the Covid rules". Although the former Conservative prime ministers, Johnson and Rishi Sunak had received fixed penalty notices for breaking Covid-19 regulations, neither had any criminal convictions. Scottish Finance Secretary Shona Robison delivers the 2024 budget, which includes planned changes to taxation and a pledge to scrap the two child benefit cap in Scotland. Welsh Conservative leader Andrew RT Davies tells BBC News Wales there has been "plotting" among Conservative Senedd members to oust him since April. Secretary of State for Northern Ireland Hilary Benn begins the process of repealing the controversial Legacy Act. 27-year-old Sam Smith is announced as the new leader of Nottinghamshire County Council. Karen Kilgour, leader of Newcastle City Council, faces a vote of no confidence. 5 December – Starmer delivers a major speech in which he sets out six objectives which he says "give the British people the power to hold our feet to the fire"; the objectives cover the economy, housebuilding, the NHS, policing, pre-school education and green energy. Questions are raised over whether Henry Tufnell, the MP for Mid and South Pembrokeshire, gave his parents advanced knowledge of plans to change inheritance tax rules after they transferred ownership of farm land to one of their sons days before the budget.
Sources: en.wikipedia.org
Registered medical products are most often 0.1% nasal drops. Research suppliers ship lyophilized powder, usually in milligram quantities, which is dissolved before use. The active peptide is the same in both cases; presentation and excipients differ.
No. The peptide is synthetic, although it is modelled on a fragment of a naturally occurring hormone. ACTH(4-10) is generated when ACTH is cleaved, but the Pro-Gly-Pro extension is not a known endogenous sequence. It is therefore a designed analogue rather than a natural metabolite.
The label reflects reported effects on attention, memory and recovery after neurological injury in regional clinical reports. Those reports are mostly small and have not been widely replicated outside the region. The classification is descriptive and does not imply a single defined mechanism.
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.