intranasal delivery raises a handful of sensible questions. This page answers them in order, starting with the fundamentals and moving to applications.
Reviewed 2025-12-31. Anything still debated is marked as such rather than presented as settled.
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.
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.
The mechanisms attributed to semax are inferred from animal and cell studies rather than traced to one confirmed target. The most frequently cited pathway involves increased expression of brain-derived neurotrophic factor and nerve growth factor in hippocampal and cortical tissue. Some work points to engagement of melanocortin receptors, particularly MC4, which the parent ACTH fragment can activate. Effects on dopaminergic and serotonergic signalling have also been reported. No single account explains all observed results, and the relative weight of each pathway remains unsettled.
Published studies examine a fairly narrow set of endpoints. Rodent experiments commonly measure maze learning, infarct volume after induced ischemia, and tissue levels of neurotrophic factors. Clinical reports from Russian centres describe attention, memory and recovery scores in patients after stroke or transient ischemic attack. Most of those human studies are small and few have been repeated by independent groups. Outcome measures differ between studies, which limits direct comparison.
Circulation time for the peptide is short because peptidases cleave it readily. The Pro-Gly-Pro tail is thought to slow breakdown compared with the bare ACTH fragment, but the gain appears modest. Absorption after intranasal dosing is limited, and only a fraction of a dose is expected to reach the central nervous system. Laboratory concentrations therefore sit well above levels achieved systemically, a gap that complicates translation from bench findings to clinical claims.
| Property | Value | Notes |
|---|---|---|
| Appearance | White to off-white powder | Lyophilised solid |
| Solubility class | Freely soluble in water | Also dissolves in aqueous buffers |
| Typical storage temperature | -20 °C | Dry, desiccated, protected from light |
| Typical analytical method | RP-HPLC with UV detection | Often paired with LC-MS |
| Water content | Reported as Karl Fischer value | Freeze-dried material is hygroscopic |
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.
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.
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.
=== Blended grain === The term blended grain Scotch refers to whisky that contains at least two single grain Scotch whiskies from at least two distilleries, combined to create one batch of the product.
=== Brand names === Estradiol cypionate has been marketed under the brand names Cicloestradiolo, D-Est, depGynogen, Depo-Estradiol, Depoestra, Depofemin, Depogen, Dura-Estrin, E-Cypionate, E-Ionate, Estradep, Estro-Cyp, Estrofem, Estroject, Estromed-PA, Estronol, Femovirin, Neoginon Depositum, Oestradiol-Retard, Pertradiol, Spendepiol, and T-E Cypionate, among others.
=== The Final Hours of Portal 2 === The Final Hours of Portal 2 is a digital book written and created by Geoff Keighley released on May 17, 2011. This digital book gives insight on the creation of Portal 2. Keighley had previously worked as an editor at GameSpot, writing several 10,000-word "Final Hours" pieces on various games where he visited the studios during the late development phases to document the creation of the game. One piece, "The Final Hours of Half-Life 2", allowed Keighley to interact with Valve during 2003 and 2004 and talk with the staff as they completed work on Half-Life 2. Keighley wanted to recreate a similar work for Portal 2, with focus on making it an interactive work for the iPad. Keighley was granted "fly on the wall" access to Valve when Portal 2 was being produced. The initial iPad release was written by Keighley with work by Joe Zeff Design, a studio that had also produced digital applications for Time magazine. The interactive work provides movie clips and short applications to demonstrate the various mechanics of the game and stages of the game's development. The work was later ported into a non-interactive eBook, and into an application with the same iPad interactivity on the Steam platform. With the iPad and Steam version, Keighley is able to offer live updates to the work; upon release of the "Peer Review" downloadable content pack, the work was updated with an additional chapter discussing the creation of the new content and what new features players could expect in the future from Portal 2.
Sources: en.wikipedia.org
Blood volume in the octopus' body is about 3.5% of its body weight but the blood's oxygen-carrying capacity is only about 4 volume percent. This contributes to their susceptibility to the oxygen debt mentioned before. Shadwick and Nilsson concluded that the octopus circulatory system is "fundamentally unsuitable for high physiologic performance". Since the binding agent is found within the plasma and not the blood cells, a limit exists to the oxygen uptake that the octopus can experience. If it were to increase the hemocyanin within its blood stream, the fluid would become too viscous for the myogenic hearts to pump. Poiseuille's law explains the rate of flow of the bulk fluid throughout the entire circulatory system through the differences of blood pressure and vascular resistance.
== Paleontology == Moscow has internationally significant paleontological monuments in its area. One of these is the Gorodnya River with its tributaries, on the banks of which are located outcrops of the Quaternary and older Cretaceous periods. Fossils of the bivalve mollusk Inoceramus kleinii and tubular passages of burrowing animals—described in 2017 as a new ichnospecies, Skolithos gorodnensis—were discovered in Coniacian deposits near the stream bed of the Bolshaya Glinka River. The trace fossils Ichnogenera Diplocraterion, Planolites, Skolithos, and possibly Ophiomorpha were found in Albian deposits. Paleolithic flint tools were discovered in the Quaternary deposits of the Bolshaya Glinka stream bed. In 1878, paleontologist Hermann Trautschold discovered the left flipper of an ichthyosaur (an extinct large marine reptile) near the village of Mnevniki, which later became part of Moscow. In 2014, this ichthyosaur was named Undorosaurus trautscholdi, after its discoverer. Trautschold determined the age of the sediments from which the specimen was taken to be Kimmeridgian; however, according to more recent studies, these sediments were formed during the Tithonian age of the Jurassic period. Other organisms—Albian foraminifera and ammonites—are also known from Moscow deposits. Fossils of various organisms are displayed in Moscow museums, including the Orlov Museum of Paleontology and the Vernadsky State Geological Museum.
High doses of some antioxidants may have harmful long-term effects. The Beta-Carotene and Retinol Efficacy Trial (CARET) study of lung cancer patients found that smokers given supplements containing beta-carotene and vitamin A had increased rates of lung cancer. These harmful effects may also be seen in non-smokers, as one meta-analysis including data from approximately 230,000 patients showed that β-carotene, vitamin A or vitamin E supplementation is associated with increased mortality, but saw no significant effect from vitamin C. No health risk was seen when all the randomized controlled studies were examined together, but an increase in mortality was detected when only high-quality and low-bias risk trials were examined separately. As the majority of these low-bias trials dealt with either elderly people, smokers, or people with disease, these results may not apply to the general population. This meta-analysis was later repeated and extended by the same authors, confirming the previous results. These two publications are consistent with some previous meta-analyses that also suggested that vitamin E supplementation increased mortality, and that antioxidant supplements increased the risk of colon cancer. In the Selenium and Vitamin E Cancer Prevention Trial (SELECT study), vitamin E – alone or combined with selenium – had no effect on the risk of prostate cancer. Beta-carotene may also increase lung cancer.
Buspirone/testosterone (tentative brand name Lybridos) is a combination of buspirone, a 5-HT1A receptor partial agonist, α2-adrenergic receptor antagonist, and D2 autoreceptor antagonist, and testosterone, an androgen or androgen receptor agonist, which is under development by the pharmaceutical company Emotional Brain for the treatment of female sexual dysfunction. Both buspirone and testosterone have individually been found to be effective in the treatment of female sexual dysfunction in clinical studies, and so their combination could be anticipated to be even more effective. As of January 2016, the combination is in phase II clinical trials, with a phase III trial being planned in the United States and Europe.
Sources: en.wikipedia.org
Reversed-phase high-performance liquid chromatography is the standard method, with detection in the ultraviolet range. Peak area percentage yields a purity figure for the main component. Mass spectrometry is normally run alongside to confirm molecular identity.
Dry lyophilised powder is generally kept at minus twenty degrees Celsius, protected from light and moisture. Repeated freeze-thaw cycles are avoided because they encourage aggregation and moisture uptake. Solutions are less stable than the solid form and degrade faster at room temperature.
A certificate documents what the supplier measured, not what an independent party confirmed. Methods, instruments and acceptance criteria can differ between suppliers. Third-party testing is the usual way to resolve discrepancies.
It consists mainly of animal experiments and small clinical reports, with much of the clinical material published in Russian-language journals. Large independent trials are scarce. Separating reliable effects from chance findings is consequently difficult.