The short version of reverse-phase HPLC fits in a sentence. The long version — which is the one that helps — is below.
This page was last updated on 2025-10-23 and is reviewed periodically as new material appears.
Proposed mechanisms center on modulation of the GABA system, but no single molecular target has been confirmed. Rodent studies report changes in GABA-A receptor expression and in the turnover of serotonin, dopamine, and norepinephrine in several brain regions. Increases in brain-derived neurotrophic factor and its receptor have also been described after repeated administration. These findings come largely from animal models, and the degree to which they describe human neurochemistry remains an open question. The mechanism is best characterized as multi-system and not fully resolved.
Pharmacokinetic data are limited. Like most short peptides, Selank is vulnerable to plasma and tissue peptidases, and its measured half-life in circulation is short, on a minutes scale. The Pro-Gly-Pro tail slows this degradation but does not eliminate it. Intranasal administration is the route described in most reports, with absorption through the nasal mucosa and a hypothesized path into the central nervous system that avoids the blood-brain barrier. Direct measurements of human brain exposure are unavailable, so distribution claims rest on inference from animal work.
Clinical evidence comes mainly from small studies conducted in Russia, several of which were open-label or lacked robust blinding. Reported outcomes include lower anxiety scores, changes in attention measures, and effects on asthenic states following illness. Sample sizes are typically in the tens of participants, and independent replication outside the region is scarce. Reviews published in English generally note the limited methodological quality of the underlying trials. Whether the compound produces clinically meaningful effects under rigorous conditions remains unresolved.
Selank is a synthetic heptapeptide with the sequence Thr-Lys-Pro-Arg-Pro-Gly-Pro, written TKPRPGP in one-letter notation. Its structure consists of the immunomodulatory tetrapeptide tuftsin, Thr-Lys-Pro-Arg, extended at the carboxyl terminus by a Pro-Gly-Pro segment. The molecular formula is commonly given as C33H57N11O9, corresponding to a monoisotopic mass near 751.4 Da and an average molecular mass near 751.9 Da. All seven residues are proteinogenic amino acids, and the molecule carries no modified side chains or non-natural linkages.
The compound was designed at the Institute of Molecular Genetics of the Russian Academy of Sciences during the 1980s and 1990s. The stated design goal was to retain the immunomodulatory and central nervous system activity attributed to tuftsin while improving resistance to enzymatic breakdown. Adding a proline-rich tail to the short parent peptide was a deliberate strategy, because proline residues restrict the conformations available to many peptidases. The same laboratory produced Semax, an ACTH fragment analog, and both compounds were developed in parallel as short, enzymatically stabilized peptides intended for intranasal use.
Selank is not a naturally occurring peptide and has no known endogenous counterpart in human physiology. Russian-language sources frequently call it TP-7, while English-language sources use the name Selank almost exclusively. Database indexing is uneven, partly because early reports appeared in regional journals that are not widely cataloged. Some summaries describe the material as a tuftsin analog and others as a synthetic heptapeptide; the labels overlap rather than conflict. Citing the primary sequence resolves ambiguity more reliably than the research or trade name alone.
| Property | Value | Notes |
|---|---|---|
| Route studied | Intranasal | Predominant route in published reports |
| Circulation stability | Short, minutes scale | Peptidases cleave it; the tail slows the process |
| Analytical method | RP-HPLC with mass spectrometry | Used for identity and purity assessment |
| Reported outcome domains | Anxiety and cognitive measures | Derived from small, mostly regional trials |
| Regulatory status | Marketed in Russia | Availability outside that market is limited |
Lyophilized material is generally stable for extended periods when kept dry at or below minus twenty degrees Celsius. Working solutions are less stable, and common practice is to aliquot and freeze them so that repeated freeze-thaw cycles are avoided. Aqueous solutions are sensitive to pH extremes and to microbial growth, so short-term storage at refrigerator temperature is typical. Oxidation and hydrolysis are the principal degradation routes. Reconstitution with sterile water or a mild buffer is standard, and solutions should be protected from light.
Regulatory treatment varies by jurisdiction. In Russia the compound is a registered prescription product, while in the European Union and the United States it is generally handled as a research chemical without a marketing authorization. Suppliers therefore operate outside pharmaceutical oversight, and buyers rely on supplier documentation for purity and identity claims. Chain of custody and third-party testing are the main verification tools. Analysts note that the absence of a pharmacopoeial monograph for research-grade material limits standardization across vendors.
Measuring peptide exposure inside the brain is technically difficult. Selank is degraded rapidly in plasma, and assays must separate intact peptide from fragments, which favors targeted mass spectrometry over immunoassays alone. Reported half-lives are short, on the order of minutes, so effects observed hours later are attributed to downstream signaling rather than to the parent compound. Blood-brain barrier permeability is debated and rarely quantified directly. Gaps include absent dose-response characterization, inconsistent reporting of purity, and almost no pharmacokinetic data from human participants.
Selank is studied chiefly as an animal-model anxiolytic with proposed secondary effects on memory and immune signaling. Reported mechanisms include modulation of the GABA-A receptor complex, inhibition of enkephalin-degrading enzymes, and shifts in monoamine turnover within limbic structures. Some experiments describe increased expression of brain-derived neurotrophic factor in the hippocampus after repeated dosing. No single molecular target has been confirmed, and the peptide does not bind any receptor with the selectivity typical of a conventional small-molecule drug. Mechanism therefore remains a set of hypotheses rather than an established pathway.
Laboratory work relies on standard behavioral paradigms. Rodents are tested in the elevated plus maze, open field, and passive avoidance tasks, with outcomes compared against diazepam or vehicle controls. Intranasal dosing is used most often because it bypasses first-pass metabolism, though intraperitoneal and intravenous routes also appear in published protocols. Biochemical endpoints include tissue BDNF concentrations, cytokine levels, and monoamine metabolites. Human data are limited to small Russian trials reporting reduced anxiety scores; most were not prospectively registered, and few employed independent outcome assessment.
Ethanol is also known chemically as alcohol, ethyl alcohol, or drinking alcohol. It is a simple alcohol with a molecular formula of C2H6O and a molecular weight of 46.0684 g/mol. The molecular formula of ethanol may also be written as CH3−CH2−OH or as C2H5−OH. The latter can also be thought of as an ethyl group linked to a hydroxyl (alcohol) group and can be abbreviated as EtOH. Ethanol is a volatile, flammable, colorless liquid with a slight characteristic odor. Aside from its use as a psychoactive and recreational substance, ethanol is also commonly used as an antiseptic and disinfectant, a chemical and medicinal solvent, and a fuel.
=== October === 1 October – PPE Medpro is ordered to pay back £122m to the government after supplying non-compliant medical gowns during the COVID-19 pandemic. 2 October – Former Conservative MP Sarah Atherton joins Reform UK and says she wants to stand in the 2026 Senedd election. Reform UK-led Nottinghamshire County Council partially lift the ban they imposed on the Nottingham Post in response to a request to lift it in full from a law firm representing the publishers. Kemi Badenoch pledges to repeal the Climate Change Act 2008. 3 October – Dame Sarah Mullally is named as the first female Archbishop of Canterbury, replacing Justin Welby following his resignation. Zack Polanski makes his keynote speech as leader of the Green Party of England and Wales at their annual conference. Shabana Mahmood calls Pro-Palestinian protests "un-British" following the 2025 Manchester synagogue attack. Michelle Mone, Baroness Mone says she has no wishes to return to the House of Lords. 4 October – The 2025 Conservative Party Conference begins in Manchester. London Assembly member Keith Prince defects from the Conservative Party to Reform UK. 5 October – The Conservatives say they would task officials with deporting 750,000 migrants over five years if they form the next government. 7 October – The Guardian publishes video footage of Robert Jenrick, the Shadow Justice Secretary, describing the Handsworth area of Birmingham as "one of the worst-integrated places" in the UK during an after dinner speech recorded in March. 20 Conservative councillors defect to Reform UK.
==== 2010-2019 ==== On March 18, 2010, Teva said it planned to acquire German generic Ratiopharm for US$5 billion. The deal was completed in August 2010, significantly expanding Teva's European coverage. In May 2011, Teva bought Cephalon for US$6.8 billion. The same month, Teva announced the ¥40 billion purchase of a majority stake in Japanese generic drug company Taiyo Pharmaceutical Industry, a move to secure a Japan-local production facility. Teva completed the $934 million acquisition in July 2011. In June 2013, Teva acquired US firm MicroDose Therapeutx for $40 million with as much as $125 million being paid in regulatory and developmental milestones In 2010, Teva announced that it would build its main distribution center for the Americas in Philadelphia, PA, and was considering opening its US headquarters in the area. In 2010, it had 39,660 employees. In Israel, the number of workers rose 7.5% by 6,774. In October 2010, Teva entered a licensing agreement with BioTime to develop and market BioTime's OpRegen for the treatment of age-related macular degeneration, an effort that in 2013 received $1.5 billion in funding from Israel's Office of the Chief Scientist. In May 2011, Teva announced it would purchase Cephalon for US$6.8 billion. In January 2014, Teva acquired NuPathe, after outbidding Endo, for $144 million. In June 2014, Teva acquired Labrys Biologics for up to $825 million, the aim being to strengthen the company's migraine pipeline through addition of LBR-101, an anti-CGRP monoclonal antibody therapeutic.
Sources: en.wikipedia.org
Electromagnetic spectrum refers to the full range of all frequencies of electromagnetic radiation and also to the characteristic distribution of electromagnetic radiation emitted or absorbed by that particular object. Devices used to measure an electromagnetic spectrum are called spectrograph or spectrometer. The visible spectrum is the part of the electromagnetic spectrum that can be seen by the human eye. The wavelength of visible light ranges from 390 to 700 nm. The absorption spectrum of a chemical element or chemical compound is the spectrum of frequencies or wavelengths of incident radiation that are absorbed by the compound due to electron transitions from a lower to a higher energy state. The emission spectrum refers to the spectrum of radiation emitted by the compound due to electron transitions from a higher to a lower energy state. Light from many different sources contains various colors, each with its own brightness or intensity. A rainbow, or prism, sends these component colors in different directions, making them individually visible at different angles. A graph of the intensity plotted against the frequency (showing the brightness of each color) is the frequency spectrum of the light. When all the visible frequencies are present equally, the perceived color of the light is white, and the spectrum is a flat line. Therefore, flat-line spectra in general are often referred to as white, whether they represent light or another type of wave phenomenon (sound, for example, or vibration in a structure).
== Activities == Think tanks may attempt to broadly inform the public by holding conferences to discuss issues which they may broadcast; encouraging scholars to give public lectures, testifying before committees of governmental bodies; publishing and widely distributing books, magazines, newsletters or journals; creating mailing lists to distribute new publications; and engaging in social media. Think tanks may privately influence policy by having their members accept bureaucratic positions, having members serve on political advisory boards, inviting policy-makers to events, allowing individuals to work at the think tank; employing former policy-makers; or preparing studies for policy makers.
Dog food is specifically formulated food intended for consumption by dogs and other related canines. Dogs are considered to be omnivores with a carnivorous bias. They have the sharp, pointed teeth and shorter gastrointestinal tracts of carnivores, better suited for the consumption of meat than of vegetable substances, yet also have ten genes that are responsible for starch and glucose digestion, as well as the ability to produce amylase, an enzyme that functions to break down carbohydrates into simple sugars – something that obligate carnivores like cats lack. Dogs evolved the ability living alongside humans in agricultural societies, as they managed on scrap leftovers and excrement from humans. Dogs have managed to adapt over thousands of years to survive on the meat and non-meat scraps and leftovers of human existence and thrive on a variety of foods, with studies suggesting dogs' ability to digest carbohydrates easily may be a key difference between dogs and wolves. The dog food recommendation should be based on nutrient suitability instead of dog's preferences. Pet owners should consider their dog's breed, size, age, and health condition and choose food that is appropriate for their dog's nutritional needs. In the United States alone, the dog food market was expected to reach $23.3 billion by 2022.
=== Erythropoietic protoporphyria === High doses of β-carotene (up to 180 mg per day) may be used as a treatment for erythropoietic protoporphyria, a rare inherited disorder of sunlight sensitivity, without toxic effects.
Sources: en.wikipedia.org
== Surgery == While weight loss is beneficial in improving glycemic control in patients with T2D, maintaining significant weight loss can be challenging. People with diabetes who have a body mass index (BMI) of 35 or higher, and who have been unable to lose weight otherwise, bariatric surgery offers a viable option to help achieve that goal. In 2018, a Patient-Centered Outcomes Research Institute funded study was published which analyzed the effects of three common types of bariatric surgery on sustained weight loss and long-lasting glycemic control in patients with T2D. The results of this study demonstrated that five years after bariatric surgery, there was significant weight loss in a large majority of patients. In addition, and more importantly, this study showed that, in patients with type 2 diabetes with a BMI of 35 or higher, bariatric surgery has the potential to lead to complete remission of diabetes in as many as 40% of those people who have the procedure. Like any operation, bariatric surgery is not without risks and complications, and those risks need to weighed against the potential benefits in anyone considering the procedure.
The Albert Einstein College of Medicine is a private medical school in New York City. Founded in 1953, Einstein is an independent degree-granting institution within the Montefiore Einstein Health System. Einstein hosts MD, PhD, and master's programs. Admission to its MD program is highly selective, with an acceptance rate of 1.85% in 2024. Joint masters are offered with the City University of New York and Yeshiva University's Cardozo School of Law. Einstein is also home to one of the first three Medical Scientist Training Programs inaugurated in 1964. This joint MD/PhD program has received continuous funding from the National Institutes of Health. Planning for the college was initiated by Yeshiva University President Samuel Belkin in 1945. Physicist Albert Einstein, who noted that the college would be unique as it would provide medical training to "students of all creeds and races", lent his name to the institution. Due to Yeshiva's financial difficulties, Einstein was transferred to Montefiore in 2015. Following a $1 billion donation to the school by Ruth Gottesman in 2024, Einstein became tuition-free for all MD students. Einstein houses several NIH-designated centers and has contributed to major medical advances, including the first coronary artery bypass surgery. Faculty members have included 18 members of the National Academy of Sciences, three National Medal of Science recipients, and neurologist and writer Oliver Sacks.
== Repackaging process and stability data == The transient or definitive displacement of the solid oral form from the original atmosphere to enter a repackaging process, sometimes automated, is likely to play a primary role in the pharmaceutical controversy in some countries. However, the solid oral dose is to be repackaged in materials with defined quality. Considering these data, a review of the literature for determination of conditions for repackaged drug stability according to different international guidelines is presented by F Lagrange.
== Research == In addition to the injectable and nasal spray dosage forms of the salmon calcitonin, noninvasive oral formulations of the peptide are currently under clinical development. The short-half-life of this peptide in serum triggered several attempts to enhance plasma concentrations. The peptide is complexed with a macromolecule that acts as an absorption enhancer through the transcellular pathway and, additionally, protects the peptide from the harsh pH and enzymatic conditions of the GI tract. This complexation is weak, noncovalent and reversible and the drug remains chemically unmodified. After passage through the intestine, the delivery agent dissociates from the peptide. One of the extensively studied oral formulations is the disodium salts of 5-CNAC oral calcitonin. This novel oral platform in a number of clinical trials at different phases has demonstrated promising enhanced pharmacokinetic profile, high bioavailability, well-established safety and comparable efficacy to that of nasal calcitonin especially for treatment of postmenopausal bone loss.
Bats are the only mammals that can truly fly. They fly through the air at a constant speed by moving their wings up and down (usually with some fore-aft movement as well). Because the animal is in motion, there is some airflow relative to its body which, combined with the velocity of the wings, generates a faster airflow moving over the wing. This generates a lift force vector pointing forwards and upwards, and a drag force vector pointing rearwards and upwards. The upwards components of these counteract gravity, keeping the body in the air, while the forward component provides thrust to counteract both the drag from the wing and from the body as a whole. The wings of bats are much thinner and consist of more bones than those of birds, allowing bats to maneuvere more accurately and fly with more lift and less drag. By folding the wings inwards towards their body on the upstroke, they use 35% less energy during flight than birds. The membranes are delicate, ripping easily; however, the tissue of the bat's membrane is able to regrow, such that small tears can heal quickly. The surface of their wings is equipped with touch-sensitive receptors on small bumps called Merkel cells, also found on human fingertips. These sensitive areas are different in bats, as each bump has a tiny hair in the center, making it even more sensitive and allowing the bat to detect and collect information about the air flowing over its wings, and to fly more efficiently by changing the shape of its wings in response.
Sources: en.wikipedia.org
Reports describe effects on GABA-A receptor expression, monoamine turnover, and neurotrophic factor levels. These are proposed mechanisms drawn mainly from animal models. No single molecular target has been established.
Intranasal delivery is the route described in most published work. It is used because the peptide is degraded quickly once it reaches circulation. Direct evidence of brain penetration in humans is lacking.
Most trials are small, regionally concentrated, and often lack rigorous blinding or placebo control. Independent replication is limited. Reviews in English generally rate the evidence as preliminary.
The sequence is Thr-Lys-Pro-Arg-Pro-Gly-Pro, written TKPRPGP in one-letter code. It combines the tetrapeptide tuftsin with a carboxyl-terminal Pro-Gly-Pro extension. This full sequence identifies the molecule more precisely than the research name.