Everything below concerns Reversed-phase HPLC. We keep the language plain, cite what the science says, and separate well-supported claims from open questions.
Last reviewed on 2025-11-14. Where a claim depends on a specific study, the study is described rather than over-claimed.
Lyophilized selank is normally supplied as a dry powder and is considered stable for extended periods when kept cold and dry. Moisture uptake is the main practical threat, because absorbed water promotes both hydrolysis and aggregation in the solid state. Vials are usually warmed to room temperature before opening so that condensation does not form on the powder. Supplier documentation commonly specifies -20 °C for routine storage, with -80 °C used for material intended to be archived for years.
Once dissolved, the peptide is markedly less stable than the dry powder. Aqueous solutions are subject to backbone hydrolysis and to microbial growth when they are handled without sterile technique. Buffered solutions near neutral pH are common for short-term laboratory work, while acidic conditions are sometimes used to improve solubility. Analytical laboratories generally prepare working solutions fresh rather than storing them, and a residual water film left in a reopened vial can seed degradation even when the container appears dry.
Selank is a hydrophilic peptide and dissolves readily in water and in aqueous buffers. The lyophilised powder is typically a white to off-white solid. Because short peptides are prone to hydrolysis and oxidation, handling benefits from limiting exposure to heat, moisture and strong light. Working solutions are commonly prepared in sterile water or saline, and repeated freeze-thaw cycles are avoided to reduce aggregation and loss of activity. These practices reflect general laboratory convention rather than published stability specifications.
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.
| Property | Value | Notes |
|---|---|---|
| Typical purity specification | 95 percent or higher by RP-HPLC | Area percentage of the main peak |
| Identity confirmation | Electrospray ionization mass spectrometry | Observed mass compared with the theoretical value near 751.9 Da |
| Recommended dry storage | -20 °C, desiccated | -80 °C for multi-year archival material |
| Solution handling | Prepare fresh; avoid long storage | Sterile filtration reduces microbial load |
| Common synonyms | TKPRPGP; TP-7 | Sequence code and laboratory designation used interchangeably |
Selank is a synthetic heptapeptide developed in Russia. Its sequence is Thr-Lys-Pro-Arg-Pro-Gly-Pro, a seven-residue chain built around the natural tetrapeptide tuftsin. Researchers at the Institute of Molecular Genetics of the Russian Academy of Sciences first described the compound in the mid-1990s. The design combined the tuftsin core with an added Pro-Gly-Pro tail, a modification intended to extend the molecule's stability in biological fluids. Published work on the peptide has appeared mainly in Russian-language journals.
Reported activity for Selank centers on anxiolytic and nootropic effects. Russian clinical reports describe use in anxiety and in cognitive or attention-related complaints. Most of this evidence comes from studies conducted by the same research groups that developed the peptide. Independent replication in other countries remains limited, and no major Western regulatory agency has approved the compound for any indication. The gap between local reports and external verification is a recurring point in discussions of the peptide.
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.
== Sources == Ovington LG (October 2002). "The evolution of wound management: ancient origins and advances of the past 20 years". Home Healthc Nurse. 20 (10): 652–6. doi:10.1097/00004045-200210000-00009. PMID 12394337. Sipos P, Gyõry H, Hagymási K, Ondrejka P, Blázovics A (February 2004). "Special wound healing methods used in ancient egypt and the mythological background". World J Surg. 28 (2): 211–6. doi:10.1007/s00268-003-7073-x. PMID 14708054. S2CID 1210892. "Dressing and Bandage Types." Wound Care. N.p., n.d. Web. 23 Nov. 2015.
Kief is a powder, rich in trichomes, that can be sifted from the leaves, flowers and fruits of cannabis plants and either consumed in powder form or compressed to produce cakes of hashish. The term derives from colloquial Arabic كيف kēf/kīf, meaning pleasure.
In 2024, the United States suffered from an "all-time high" scarcity of over three hundred different kinds of drugs and medications in healthcare and pharmacy settings, surpassing the number of drug shortages present in 2014. Drugs and medications impacted by the shortage included asthma medications, anesthesia and analgesic medications, psychiatric medications for conditions such as ADHD, depression, and bipolar disorder; diabetic medications, injectable sterile drugs, emergency medications stored in rapid response carts, and chemotherapy drugs for cancer patients. Most of the named drug shortages present in the initial April 2024 report were still occurring as of July 2024.
Sources: en.wikipedia.org
== Research == Friedler's research is in chemical biology, peptide chemistry, protein chemistry, biophysical chemistry, and medicinal chemistry. It focuses on the use of peptides and peptide-based methods to study and inhibit protein–protein interactions, with a particular focus on interactions involving intrinsically disordered protein regions. His work has used synthetic, structural and biophysical approaches to investigate the molecular basis of these interactions and peptide-based methods to modulate them. His research has examined interactions involving the tumour-suppressor protein p53, including its interactions with MDM2. His work has also addressed proteins associated with apoptosis and cancer-related signalling pathways. He has also studied interactions among HIV-1 proteins, including integrase, Rev, Vif, and Tat, and peptide-based approaches to influencing viral protein interactions. A particular focus of Friedler's research has been the use of intrinsically disordered proteins as therapeutic targets and as sources for peptide inhibitors of protein–protein interactions. Other work by Friedler and his collaborators has addressed protein oligomerisation and protein aggregation, including amyloid formation and the aggregation of proteins associated with cancer and neurodegenerative disease. His more recent research has also included methods for synthesizing multiphosphorylated peptides and protein-interaction-based biosensors.
Xaa-Pro dipeptidase, also known as prolidase, is an enzyme that in humans is encoded by the PEPD gene. Prolidase is an enzyme in humans that plays a crucial role in protein metabolism and collagen recycling through the catalysis of the rate-limiting step in these chemical reactions. This enzyme is coded by the gene PEPD (peptidase D), located on chromosome 19. Serum prolidase activity is also currently being explored as a biomarker for diseases.
==== Loan to Queens Park Rangers ==== On 31 January 2013, Townsend followed Redknapp to Premier League club Queens Park Rangers on loan until the end of the season. He made twelve appearances for the club, including a Man of the Match performance on his debut, scoring two goals in March, a dipping volley from outside the penalty area in a 3–1 win at home to Sunderland, and an equalising deflection in a 3–2 away loss to Aston Villa. QPR were ultimately relegated, and Townsend returned to his parent club.
Sources: en.wikipedia.org
=== Web search === Microsoft introduced Copilot Search in February 2023 under the name Bing Chat. Copilot Search provides AI-generated summaries. Generative AI features added to Google Search include AI Overviews in May 2024 and AI Mode in May 2025.
In May 1945, Czechoslovak troops took possession of the borderland. A Czechoslovak administrative commission composed exclusively of Czechs was established. Sudeten Germans were subjected to restrictive measures and conscripted for compulsory labor. On 15 June, however, Beneš called Czechoslovak authorities to order. In July, Czechoslovak representatives addressed the Potsdam Conference (the U.S., Britain and the Soviet Union) and presented plans for a "humane and orderly transfer" of the Sudeten German population. There were substantial exceptions from expulsions that applied to about 244,000 ethnic Germans who were allowed to remain in Czechoslovakia. The following groups of ethnic Germans were not deported:
=== Fertility support === Progesterone is used for luteal support in assisted reproductive technology (ART) cycles such as in vitro fertilization (IVF). It is also used to correct luteal phase deficiency to prepare the endometrium for implantation in infertility therapy and is used to support early pregnancy.
A Squadron: 1 (Boat) Troop – 2 (Air) Troop – 3 (Mobility) Troop – 4 (Mountain) Troop B Squadron: 6 (Boat) Troop – 7 (Air) Troop – 8 (Mobility) Troop – 9 (Mountain) Troop D Squadron: 16 (Air) Troop – 17 (Boat) Troop – 18 (Mobility) Troop – 19 (Mountain) Troop G Squadron: 21 (Mobility) Troop – 22 (Mountain) Troop – 23 (Boat) Troop – 24 (Air) Troop
Sources: en.wikipedia.org
Sealed, desiccated storage at -20 °C or colder is the standard recommendation for research-grade material. Vials should reach room temperature before they are opened, which limits condensation. Repeated temperature cycling is discouraged.
A reported purity value reflects the share of the main peak in one chromatographic run and says nothing about identity. Confirming that the expected sequence is present requires a separate measurement such as mass spectrometry. Purity and identity are distinct questions.
A mass spectrum reports the molecular masses present in a sample and shows whether they match the value expected for selank, near 751.9 Da. It also flags common artifacts such as truncation or adduct formation. It does not establish correct stereochemistry or complete sequence order on its own.
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.