The short version of reversed-phase HPLC fits in a sentence. The long version — which is the one that helps — is below.
This page was last updated on 2026-01-21 and is reviewed periodically as new material appears.
Handling follows standard practice for research peptides. Material is weighed in a low-humidity environment because the powder absorbs atmospheric moisture. Purity is reported as the percentage area of the main peak in a chromatogram, with specifications commonly set at 95 percent or higher; values below that threshold indicate the presence of truncated or modified species. Residual trifluoroacetate from purification is often present and may affect mass balance. Certificates of analysis should state the analytical method, the column and gradient used, and the lot-specific retention time so that results can be compared across suppliers.
Identity and purity of selank are established with reversed-phase high-performance liquid chromatography coupled to mass spectrometry. The peptide elutes from C18 columns with acetonitrile gradients in water containing trifluoroacetic acid or formic acid, and detection is usually performed by ultraviolet absorbance near 214 nm. Electrospray ionization in positive mode gives a doubly protonated ion near m/z 377, consistent with a mass of about 752 Da. Amino acid analysis or tandem mass spectrometry of fragment ions confirms the sequence. Because the molecule has no aromatic residues, it lacks a usable 280 nm chromophore, so low-wavelength detection or mass spectrometry is required.
Peptide bonds in selank are susceptible to hydrolysis under strongly acidic or basic conditions, and the terminal proline residues are vulnerable to exopeptidase activity in biological samples. Lyophilized powder stored dry at -20 °C typically remains stable for extended periods, whereas aqueous solutions degrade faster and may lose measurable purity within days to weeks depending on pH, temperature, and microbial load. Repeated freeze-thaw cycles promote aggregation and adsorption to container surfaces. For analytical work, solutions are usually prepared fresh, kept cold, and used within a single working day.
Dry powder is normally held at -20 degrees Celsius or lower, in a sealed container with desiccant and protection from light. Reconstituted solutions are usually kept at 2 to 8 degrees Celsius for short periods and frozen for longer ones. Proline residues at several positions are generally associated with some resistance to peptidase attack, but chemical stability still declines at neutral to alkaline pH and at elevated temperature. Exact shelf-life figures are product-specific and are not standardised across suppliers.
Identity and purity are usually assessed by reversed-phase high-performance liquid chromatography, with mass spectrometry used to confirm molecular mass and sequence information. Amino acid analysis and peptide mapping may supplement these methods. Certified reference standards are scarce, and many commercial lots are sold as research chemicals without a pharmacopoeial monograph. Regulatory treatment differs by country: Selank is a registered prescription medicine in Russia, while in the European Union and the United States it is not an approved drug and may fall under research-chemical or unapproved-product frameworks.
| Property | Value | Notes |
|---|---|---|
| Identity confirmation | Reversed-phase HPLC retention time versus reference standard | Retention depends on column, gradient, and ion-pairing agent |
| Mass confirmation | Electrospray or MALDI mass spectrometry | Doubly protonated ion near m/z 377 is consistent with about 752 Da |
| Typical purity specification | 95 percent or higher by chromatographic peak area | Lower values suggest truncated or modified peptide species |
| Storage of lyophilized powder | -20 °C, desiccated, protected from light | Powder tolerates long storage better than solution |
| Storage of solution | 2-8 °C for short periods | Freeze-thaw cycling promotes aggregation and surface adsorption |
Regulatory status differs sharply by region. Selank holds a Russian marketing authorization, where it is supplied mainly as nasal drops, while authorities elsewhere have not approved it for medical use. Material sold internationally is therefore usually labeled as a research chemical rather than a medicine. Peer-reviewed publications come predominantly from Russian laboratories, and sample sizes are generally small. Whether the compound produces comparable effects under independent, well-controlled replication remains an open question that the broader literature has not settled.
Selank is a synthetic heptapeptide developed in Russia as a structural analogue of tuftsin, a naturally occurring immunomodulatory tetrapeptide. Its sequence, Thr-Lys-Pro-Arg-Pro-Gly-Pro, keeps the tuftsin core at the N-terminus and appends a Pro-Gly-Pro tail. Researchers at the Institute of Molecular Genetics in Moscow synthesized the compound during the 1990s while searching for peptides with combined anxiolytic and immunomodulatory activity. The added tail was intended to resist enzymatic cleavage and prolong the molecule's presence in circulation.
Outside its country of origin the compound is generally handled as a research chemical rather than an approved medicine. No regulatory approval from the United States Food and Drug Administration or the European Medicines Agency has been granted for human use. Identity and purity are normally checked by reverse-phase high-performance liquid chromatography, with mass spectrometry used to confirm the molecular mass. Lyophilised material is stored cold and desiccated, and repeated freeze-thaw cycles are avoided.
Published work on this peptide almost always uses intranasal delivery, with drops or a spray applied to the nasal mucosa. Some animal experiments have used subcutaneous or intraperitoneal injection, and a smaller number have compared routes directly. Oral administration is not a focus of the literature, because short peptides of this size are broken down by digestive enzymes and cross intestinal barriers poorly. How much of an intranasal dose reaches the bloodstream intact in humans remains an open question.
22 July – A study proposes polymetallic nodules produce oxygen without light on the abyssal seafloor, with relevance to potential deep sea mining. 29 July – Scientists publish research on the simulation of gravitational waves from a failing warp drive. 30 July A study (19 April) on North Sea oil and gas extraction finds that pollution can spike by more than 10,000% within half a kilometre around offshore drilling sites. The world's first fully automated dental procedure on a human is reported by Boston company Perceptive. Promising results of health and medical research are reported: researchers report an apparent substantially improved prognoses of head and neck cancers if Fusobacterium is present in the patient's oral microbiome, a common bacteria of mouths thought to make bowel cancer worse (6 July), phase 3-trialed lenacapavir for HIV prevention (24 July). Hazard research is published: a study finds electric cars pose a twice as large collision risk to pedestrians in cities than internal combustion engine cars, likely largely due to being quieter (10 July), and a study reports substantial heavy metal contamination of cocoa products (31 July).
== History == The disease was first noted by German pathologist Karl Theodor Fahr in 1930. A less common name for the condition is Chavany-Brunhes syndrome and Fritsche's syndrome, the former named after Jacques Brunhes, Jean Alfred Émile Chavany, while the later named after R. Fritsche. Fewer than 20 families had been reported in the literature up to 1997.
The Central Board of Secondary Education (CBSE) is a national-level board of education in India for public and private schools, controlled and managed by the Government of India. Established in 1929 by a government resolution, the Board was an experiment in inter-state integration and cooperation in the sphere of secondary education. There are more than 27,000 schools in India and 240 schools in 28 foreign countries affiliated with the CBSE. All schools affiliated with CBSE follow the NCERT curriculum, especially those in classes 9 to 12. The current Chairperson of CBSE is Lokhande Prashant Sitaram, IAS The constitution of the Board was amended in 1952 to give its present name, the Central Board of Secondary Education. The Board was reconstituted on 1 July 1962 to make its services available to students and various educational institutions across the country.
Glutathione S-transferase A1 is an enzyme that in humans is encoded by the GSTA1 gene. Cytosolic and membrane-bound forms of glutathione S-transferase are encoded by two distinct supergene families. These enzymes function in the detoxification of electrophilic compounds, including carcinogens, therapeutic drugs, environmental toxins and products of oxidative stress, by conjugation with glutathione. The genes encoding these enzymes are known to be highly polymorphic. These genetic variations can change an individual's susceptibility to carcinogens and toxins as well as affect the toxicity and efficacy of some drugs. At present, eight distinct classes of the soluble cytoplasmic mammalian glutathione S-transferases have been identified: alpha, kappa, mu, omega, pi, sigma, theta and zeta. This gene encodes a glutathione S-transferase belonging to the alpha class. The alpha class genes, located in a cluster mapped to chromosome 6, are the most abundantly expressed glutathione S-transferases in liver (hepatocytes) and kidney (proximal tubules). In addition to metabolizing bilirubin and certain anti-cancer drugs in the liver, the alpha class of these enzymes exhibit glutathione peroxidase activity, thereby protecting the cells from reactive oxygen species and the products of peroxidation.
Sources: en.wikipedia.org
== Sponsorship and philanthropy == In 1972, Church's Chicken sponsored The San Antonio Church's Fried Chicken Inc. First International Chess Tournament, with a first prize of $4,000, resulting in the strongest chess tournament in the United States in 50 years. From 1979 to 1986, Church's Chicken sponsored the ChessCafe Grand Prix tournaments, under the auspices of the United States Chess Federation. Church's Partners Foundation, Inc. is a 501(c)(3) charity that supports the employees of franchisees of Church's Chicken, their families and their communities. The foundation awards $1,000 scholarships to American high school students through their Church's Scholars Program and awarded over $227,000 worth of scholarships in the 2018–2019 academic year. Church's Chicken has partnered with No Kid Hungry since 2016.
Keratotomies are a group of corneal procedures. Radial keratotomy is a refractive surgery procedure where the surgeon makes a spoke-like pattern of incisions into the cornea to modify its shape. This early surgical option for myopia has been largely superseded by PRK, LASIK and other similar laser procedures. Laser surgery is usually contraindicated in keratoconus and other corneal thinning conditions, as removal of corneal stromal tissue will further damage an already thin and weak cornea. For similar reasons, radial keratotomy has also generally not been used for people with keratoconus. However, more modern and keratoconus-specific variants, such as Mini asymmetric radial keratotomy (MARK) and Circular keratotomy (CK), have been found to be useful in keratoconus management, particularly when combined with Corneal cross-linking.
== Mechanism of action == Two main ideas about how it might work have been proposed over the years. The first idea, which has been proven wrong, is that insulin makes cells more permeable, so that the chemotherapy drugs are absorbed faster into cells. The other idea is that insulin might cause the cells to start dividing, which makes them more susceptible to destruction of many cytotoxic chemotherapy drugs.
== Function == The melanocortin system is one of the mammalian body's tools to regulate food intake in a push-pull fashion. The only neurons known to release melanocortins are located in the arcuate nucleus of the hypothalamus. However, melanocortins are also produced by keratinocytes in response to UV exposure. Accordingly, there is a subpopulation called POMC neurons and one called AgRP neurons. When POMC neurons release α-MSH, appetite is decreased. On the other hand, when AgRP neurons release AgRP, appetite is stimulated. Leptin, the energy surfeit hormone, and Ghrelin, the hunger hormone, are upstream regulators of the melanocortin system in the brain. These hormones also regulate the release of peptides other than the melanocortins. Disturbance of the leptin-melanocortin pathway can lead to early onset obesity as well as various metabolic disorders and suppressed immune function.
== Function == In mice, the agouti gene encodes a paracrine signalling molecule that causes hair follicle melanocytes to synthesize the yellow pigment pheomelanin instead of the black or brown pigment eumelanin. Pleiotropic effects of constitutive expression of the mouse gene include adult-onset obesity, increased tumor susceptibility, and premature infertility. This gene is highly similar to the mouse gene and encodes a secreted protein that may (1) affect the quality of hair pigmentation, (2) act as an inverse agonist of alpha-melanocyte-stimulating hormone, (3) play a role in neuroendocrine aspects of melanocortin action, and (4) have a functional role in regulating lipid metabolism in adipocytes. In mice, the wild type agouti allele (A) presents a grey phenotype, however, many allele variants have been identified through genetic analyses, which result in a wide range of phenotypes distinct from the typical grey coat. The most widely studied allele variants are the lethal yellow mutation (Ay) and the viable yellow mutation (Avy) which are caused by ectopic expression of agouti. These mutations are also associated with yellow obese syndrome which is characterized by early onset obesity, hyperinsulinemia and tumorigenesis. The murine agouti gene locus is found on chromosome 2 and encodes a 131 amino acid protein. This protein signals the distribution of melanin pigments in epithelial melanocytes located at the base of hair follicles with expression being more sensitive on ventral hair than on dorsal hair.
Sources: en.wikipedia.org
== Use during the 2018-19 Kivu Ebola outbreak in the Democratic Republic of the Congo == The ZMapp cocktail was assessed by the World Health Organization for emergency use under the Monitored Emergency Use of Unregistered and Investigational Interventions (MEURI) ethical protocol. The panel agreed that "the benefits of ZMapp outweigh its risks" while noting that it presented logistical challenges, particularly that of requiring a cold chain for distribution and storage. Four alternative therapies (remdesivir, the Regeneron product atoltivimab/maftivimab/odesivimab, favipiravir, and ansuvimab) were also considered for use, but they were at earlier stages of development. In August 2019, the Democratic Republic of the Congo's national health authorities, the World Health Organization, and the National Institutes of Health announced that they would stop using ZMapp, along with all other Ebola treatments except atoltivimab/maftivimab/odesivimab and ansuvimab, in their ongoing clinical trials, citing the higher mortality rates of patients not treated with atoltivimab/maftivimab/odesivimab and ansuvimab. In October 2020, the US Food and Drug Administration (FDA) approved atoltivimab/maftivimab/odesivimab with an indication for the treatment of infection caused by Zaire ebolavirus.
== Adaptations == In 2000, Yahoo! reported that MGM and actor/director Tom Hanks were in discussions regarding adapting both 2061: Odyssey Three and 3001: The Final Odyssey into movies, with Hanks reportedly to play Frank Poole in the 3001 film. An update in 2001 stated that there was no further development on the project. On 3 November 2014, it was reported that the US TV channel Syfy had ordered a miniseries adaptation of 3001: The Final Odyssey into production, planned for broadcast in 2015. The miniseries would be executive-produced by Ridley Scott, David W. Zucker and Stuart Beattie; the latter would also be the primary script-writer. The estates of both Clarke and 2001: A Space Odyssey director Stanley Kubrick were reported as having "offered their full support", but the extent of their involvement was not known at the time. In February 2016, within Syfy's press release for its television pilot Prototype, other series including the Final Odyssey series were mentioned as being in development. However, to date, no further progress has been made. The plot of Futurama has similarities, with the character of Fry being frozen for 1000 years (albeit in 1999) and waking in the year 3000.
=== Bibliography === Barrett, Kim E. (2019). Ganong's review of medical physiology. Barman, Susan M.,, Brooks, Heddwen L., Yuan, Jason X.-J. (26th ed.). New York. ISBN 978-1-260-12240-4. OCLC 1076268769.{{cite book}}: CS1 maint: location missing publisher (link) Beger HG, ed. (2018). The pancreas: an integrated textbook of basic science, medicine, and surgery (third ed.). Hoboken, NJ. ISBN 978-1-119-18841-4. OCLC 1065547789.{{cite book}}: CS1 maint: location missing publisher (link) Kasper D, Fauci A, Hauser S, Longo D, Jameson J, Loscalzo J (2015). Harrison's Principles of Internal Medicine (19 ed.). McGraw-Hill Professional. ISBN 978-0-07-180215-4. Ralston SH, Penman ID, Strachan MW, Hobson RP, eds. (2018). Davidson's principles and practice of medicine (23rd ed.). Elsevier. ISBN 978-0-7020-7028-0. Standring, Susan; Borley, Neil R.; et al., eds. (2008). Gray's anatomy: the anatomical basis of clinical practice (40th ed.). London: Churchill Livingstone. ISBN 978-0-8089-2371-8. Standring, Susan, ed. (2016). Gray's anatomy: the anatomical basis of clinical practice (41st ed.). Philadelphia. ISBN 978-0-7020-5230-9. OCLC 920806541.{{cite book}}: CS1 maint: location missing publisher (link) Young, Barbara; O'Dowd, Geraldine; Woodford, Phillip (2013). Wheater's functional histology: a text and colour atlas (6th ed.). Philadelphia: Elsevier. ISBN 978-0-7020-4747-3.
The following is a list of episodes for the reality television cooking series Halloween Baking Championship on Food Network. Judges are Carla Hall (season 1-11), Sherry Yard (season 1), Ron Ben-Israel (season 1), Sandra Lee (season 2), Damiano Carrara (season 2), Zac Young (season 3+), Lorraine Pascal (season 3–4), Katie Lee (season 5), Stephanie Boswell (season 6+), and Aarti Sequeira (season 12+).
==== United States ==== As of 2018, Zipline was working with the FAA to develop rules for drone operation beyond the line of sight. During the COVID-19 pandemic in 2020, the FAA granted a Part 107 waiver to Novant Health in partnership with Zipline for the delivery of medical supplies and personal protective equipment to facilities in North Carolina. The company plans to offer deliveries to homes. On November 18, 2021, Zipline started a trial service with Walmart for e-commerce shopping deliveries in Pea Ridge, Arkansas. The service, selectable to online shoppers using a special mobile app, could deliver to all residences within 50 miles (80 km) of a particular Walmart store in Pea Ridge during daylight hours. On June 21, 2022, the license "Package Delivery by Drone (Part 135)" was granted. On October 4, 2022, Zipline began commercial delivery services in Salt Lake City, Utah, in partnership with Intermountain Healthcare. On September 18, 2023, the FAA announced it had authorized Zipline to begin making commercial deliveries beyond the line of sight without visual observers. In April 2025, Zipline began making deliveries for Walmart in the Dallas–Fort Worth metroplex using Platform 2 drones.
Sources: en.wikipedia.org
Identity is confirmed by matching the retention time in reversed-phase chromatography against a reference standard and by measuring the molecular mass with mass spectrometry. Tandem mass spectrometry or amino acid analysis can verify the sequence of the seven residues. Because the peptide contains no aromatic amino acids, detection at 280 nm is not useful.
Lyophilized powder is normally stored desiccated at -20 °C, protected from light and moisture. Powder kept under these conditions is generally stable for long periods. Solutions are less stable and are usually prepared immediately before use.
A purity value from one chromatographic method does not capture every possible impurity. Related peptides with similar retention behavior, counterions, and residual solvents may not appear in the same analysis. Independent testing with an orthogonal method provides stronger assurance of identity and content.
Dry powder is normally held at -20 degrees Celsius or below in a sealed, light-protected container with desiccant. Brief room-temperature handling during weighing is generally tolerated. Storage instructions vary between suppliers, so the accompanying certificate of analysis should be followed.