reversed-phase HPLC 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 2025-09-27. Where a claim depends on a specific study, the study is described rather than over-claimed.
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.
Semax binds to melanocortin receptors and is thought to influence neuronal survival and plasticity rather than to act through the adrenal axis. Laboratory work has shown increased expression of brain-derived neurotrophic factor and nerve growth factor in treated tissue. Changes in c-Fos, a marker of neuronal activation, have also been reported. Because the peptide is rapidly degraded by peptidases, its effects are generally attributed to downstream signaling cascades rather than to sustained receptor occupancy.
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.
Clinical reports describe use in ischaemic stroke, transient ischaemic attack, optic nerve conditions, and cognitive complaints, but most of these studies are small and were conducted in a single region. Systematic reviews have generally described the evidence base as limited in size and variable in methodological quality. Randomised controlled data suitable for international regulatory assessment are scarce. As a result, major treatment guidelines outside Russia do not include the peptide, and interest in it remains largely research-driven rather than routine clinical.
Semax is a synthetic heptapeptide with the sequence Met-Glu-His-Phe-Pro-Gly-Pro. It is described in the literature as an analogue of the ACTH(4–10) fragment, a short N-terminal portion of adrenocorticotropic hormone that retains some neurotropic activity without the full hormonal effects of the parent peptide. The molecule carries a methionine residue at the N-terminus and two proline residues near the C-terminus, features that shape both its interactions with receptor systems and its chemical stability. The free peptide corresponds to the formula C37H51N9O10S and a molecular mass near 813.9 Da.
| Property | Value | Notes |
|---|---|---|
| Appearance | White lyophilized powder | Typical for synthetic peptides |
| Solubility | Freely soluble in water | Also soluble in saline |
| Storage temperature | -20 C or below | Protect from repeated freeze-thaw |
| Analytical method | Reverse-phase HPLC | Confirms purity and identity |
| Common synonym | ACTH(4-10) analog | Reflects structural origin |
Quality documentation for research-grade peptide usually includes a certificate of analysis stating purity, identity, and residual counterion content. Batch-to-batch variation in purity and salt form is a recognized issue, and comparisons across suppliers require attention to the exact counterion, for example acetate versus trifluoroacetate. Sequence verification by tandem mass spectrometry provides stronger evidence than a single mass measurement. For any study reporting biological results, the analytical method and the measured purity should be stated explicitly. Independent verification of supplier claims is considered good 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.
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.
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.
== Practical applications == With the human genome sequenced, the next step is the verification and functional annotation of all predicted genes and their protein products. Shotgun proteomics can be used for functional classification or comparative analysis of these protein products. It can be used in projects ranging from large-scale whole proteome to focusing on a single protein family. It can be done in research labs or commercially.
=== Gas fill === Most modern bulbs are filled with an inert gas to reduce evaporation of the filament and prevent its oxidation. The gas is at a pressure of about 70 kPa (0.7 atm). The gas reduces evaporation of the filament, but the fill must be chosen carefully to avoid introducing significant heat losses. For these properties, chemical inertness and high atomic or molecular weight is desirable. The presence of gas keeps the tungsten below its vapor pressure, allowing it to be operated at higher temperature without reducing its life (or, for operating at the same temperature, prolongs the filament life). On the other hand, the presence of the gas leads to heat loss from the filament—and therefore efficiency loss due to reduced incandescence—by heat conduction and heat convection. Early lamps used only a vacuum to protect the filament from oxygen. The vacuum increases evaporation of the filament but eliminates two modes of heat loss. Some small modern lamps use vacuum as well. The most commonly used fills are:
He ended by stating that he would continue to post the names of people he believed were collaborators in the Cuban regime. Ángel Santiesteban Prats reported that he believed that the State Security Unit would most likely use the situation to take Viñas Alonso away from the office of Grand Commander, writing that: "[President Díaz-Canel and State Security] never forgave [Viñas Alonso]. He's become a 'counterrevolutionary.'"
=== 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.
Sources: en.wikipedia.org
Acrylfentanyl (also known as acryloylfentanyl) is a highly potent opioid analgesic that is an analog of fentanyl and has been sold online as a designer drug. In animal studies the IC50 (the half maximal inhibitory concentration for acrylfentanyl to displace naloxone) is 1.4 nM, being slightly more potent than fentanyl itself (1.6 nM) as well as having a longer duration of action.
== Equipment == The facility has a custom-made 3 mega-volt tandem accelerator mass spectrometer. It also has a 200 sample ion source, a high resolution, 120° injection magnet, a 90° high energy analysis magnet (mass-energy product 350 MeV-AMU), a 65°, 1.7 m radius electric analyzer and a 2 channel gas ionization detector. The spectrometer weighs around 44 tons and is around 25 metres long. The facility can be seen through a two-storey window in the lobby of the Advanced Research Complex. The spectrometer accelerates the isotopes to a very high speed with almost no contamination, thus allowing for the detection of trace isotopes at very low levels.
Jurewizc further argues that the rest of the twelve nidanas show similarities with the terms and ideas found in Vedic cosmogeny, especially as it relates to the sacrificial fire (as a metaphor for desire and existence). These Vedic terms may have been adopted by the Buddha to communicate his message of not-self because his audience (often educated in Vedic thought) would understand their basic meaning. According to Jurewizc, dependent origination replicates the general Vedic creation model, but negates its metaphysics and its morals. Furthermore, Jurewizc argues that:This deprives the Vedic cosmogony of its positive meaning as the successful activity of the Absolute and presents it as a chain of absurd, meaningless changes which could only result in the repeated death of anyone who would reproduce this cosmogonic process in ritual activity and everyday life.According to Gombrich, the Buddhist tradition soon lost sight of their connection with the Vedic worldview that the Buddha was critiquing in the first four links of dependent origination. Though it was aware that at the fourth link there should be an appearance of an individual person, the Buddhist tradition equated rupa with the first skandha, and nama with the other four skandhas. Yet, as Gombrich notes, samkhara, vijnana, and vedana also appear as separate links in the twelvefold list, so this equation can't be correct for this nidana.
Sources: en.wikipedia.org
All three ethanolamines are produced in the process, while ammonia and part of methylamine are recycled. The final products are separated by vacuum distillation. Hydroxyalkylamines are produced in a similar process:
Bernice Rubens, novelist Miri Rubin (born 1956), historian and Professor of Medieval and Early Modern History at Queen Mary University of London and author of over ten scholarly academic texts and monographs on religion and the Middle Ages; educated at the Hebrew University of Jerusalem and the University of Cambridge; Rubin writes about social and religious history of Europe between 1100 and 1500, concentrating on interactions between public rituals, power, and community life. Oliver Sacks (9 July 1933 – 30 August 2015), neurologist, naturalist, historian of science, and writer of over twenty books, screenplays and scholarly articles, amongst them, 1973 book Awakenings, which was adapted into an Academy Award-nominated feature film in 1990, starring Robin Williams and Robert De Niro. Nina Salaman, (n15 July 1877 – 22 February 1925) was a British Jewish poet, translator, and social activist. Aside from her original poetry, she is best known for her English translations of medieval Hebrew verse—especially of the poems of Judah Halevi—which she began publishing at the age of 16. Maurice Samuel (1895 – 1972), author of the book You Gentiles, which is controversial for its portrayal of Jews and Gentiles as fundamentally distinct and incompatible civilisations. Samuel's depiction of enduring cultural and psychological differences between the two groups has been described by some critics as implying a form of Jewish supremacy and civilisational separatism.
== History == The market-leading RAST methodology was invented and marketed in 1974 by Pharmacia Diagnostics AB, Uppsala, Sweden, and the acronym RAST is actually a brand name. In 1989, Pharmacia Diagnostics AB replaced it with a superior test named the ImmunoCAP Specific IgE blood test, which literature may also describe as: CAP RAST, CAP FEIA (fluorenzymeimmunoassay), and Pharmacia CAP. A review of applicable quality assessment programs shows that this new test has replaced the original RAST in approximately 80% of the world's commercial clinical laboratories, where specific IgE testing is performed. The newest version, the ImmunoCAP Specific IgE 0–100, is the only specific IgE assay to receive FDA approval to quantitatively report to its detection limit of 0.1kU/L. This clearance is based on the CLSI/NCCLS-17A Limits of Detection and Limits of Quantitation, October 2004 guideline.The guidelines for diagnosis and management of food allergy issues by the National Institute of Health state that: In 2010 the United States National Institute of Allergy and Infectious Diseases recommended that the RAST measurements of specific immunoglobulin E for the diagnosis of allergy be abandoned in favor of testing with more sensitive fluorescence enzyme-labeled assays.
=== Controversy === The British critical psychiatrist Joanna Moncrieff has critiqued the use and study of esketamine and ketamine as well as related drugs like psychedelics for treatment of psychiatric disorders, highlighting concerns including excessive hype around these drugs, questionable biologically based theories of benefit, blurred lines between medical and recreational use, flawed clinical trial findings, financial conflicts of interest, strong expectancy effects and large placebo responses, small and short-term benefits over placebo, and their potential for difficult experiences and adverse effects, among others.
Sources: en.wikipedia.org
It is associated with the melanocortin receptor family, particularly subtypes found in the central nervous system. This interaction is separate from the adrenal pathway activated by full-length ACTH.
Peptidases degrade the compound within minutes in circulation. This short half-life is one reason nasal delivery is used, placing the substance close to the olfactory and trigeminal pathways.
No large multicenter trials have been published in English-language journals. The existing human evidence consists mainly of smaller studies conducted in Russia, which limits generalization.
It is described as a synthetic analogue of the ACTH(4–10) fragment, a short segment of adrenocorticotropic hormone. Its sequence differs from that fragment and includes two proline residues, which influence stability and behaviour in solution.