batch purity 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.
Updated 2026-08-01. Numbers and descriptions here follow the published literature rather than marketing material.
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.
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.
Lyophilised material kept dry at minus 20 degrees Celsius or colder is the most stable form, and suppliers commonly state a shelf life of two years or more under those conditions. Once dissolved, degradation accelerates through hydrolysis and deamidation, particularly at alkaline pH or elevated temperature. Working solutions are usually divided into single-use aliquots to avoid repeated freeze-thaw cycles. The choice of reconstitution solvent affects both stability and the ionic strength of the final preparation.
Reverse-phase high-performance liquid chromatography with ultraviolet detection near 214 nanometres is the standard purity method. Mass spectrometry, typically electrospray ionisation, confirms identity through the expected mass-to-charge pattern. Amino acid analysis can verify composition independently. Chiral purity requires separate techniques such as derivatisation followed by chromatographic separation, and such data are rarely reported for research-grade material.
| Property | Value | Notes |
|---|---|---|
| Peptide sequence | Thr-Lys-Pro-Arg-Pro-Gly-Pro | Seven residues; tuftsin plus a Pro-Gly-Pro tail |
| Molecular formula | C33H57N11O9 | Commonly reported value for the free peptide |
| Monoisotopic mass | Roughly 751.4 Da | Average molecular mass near 751.9 Da |
| Appearance | White to off-white powder | Typically supplied as a lyophilized solid |
| Solubility class | Freely soluble in water | Also dissolves in saline and other polar solvents |
Naming conventions place Selank in the same research family as Semax, another Russian-developed peptide investigated for cognitive effects. The two compounds share a lineage but differ in sequence and in the biological systems proposed as their targets. Semax descends from ACTH fragments, whereas Selank descends from tuftsin. Publications sometimes identify Selank by its full peptide sequence or by laboratory codes rather than one uniform trade name. Because replication outside Russia is limited, reports on its properties are best read alongside the study design and the purity of the material tested.
Selank is a synthetic heptapeptide developed in Russia during the 1990s. Researchers at the Institute of Molecular Genetics of the Russian Academy of Sciences designed it as a stabilized analog of tuftsin, a naturally occurring immunomodulatory tetrapeptide. The compound has been studied primarily for its reported anxiolytic and nootropic effects. It remains largely unknown in Western pharmacology and is not approved as a medicine by major regulators such as the FDA or the EMA.
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.
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.
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.
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.
The compound has a calculated molecular weight near 751.9 daltons and carries a net positive charge at physiological pH because of its arginine residue. It dissolves freely in water and in common aqueous buffers, and typically appears as a white or off-white lyophilized powder. The amide backbone makes the molecule susceptible to peptidases, which limits oral use and favors intranasal or parenteral routes. Nomenclature in the literature varies: the substance is also described by the sequence abbreviation TP-7 and by a Russian trade designation.
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.
== Chemistry and pharmacokinetics == Phenformin hydrochloride is a white crystalline powder, with a melting point of 175–178 °C; it is soluble at 1 in 8 parts of water and 1 in 15 of ethanol, and practically insoluble in chloroform and ether. Phenformin is less polar and more lipid soluble and exhibits a higher affinity for mitochondrial membranes than metformin. Its dissociation constant (pKa) is 2.7, 11.8 (at 32 °C), and log P = –0.8. Phenformin is well absorbed after oral administration. The major metabolic reaction is aromatic hydroxylation to form 4-hydroxyphenformin, which is then conjugated with glucuronic acid. Up to about 50% of a dose is excreted in the urine in 24 h, about two–thirds in the form of unchanged drug and one–third as the hydroxy metabolite. Following a single oral dose of 50 mg to eight subjects, peak plasma concentrations of 0.08–0.18 mg/L (mean 0.13) were attained in about 3 h; plasma concentrations were higher in four subjects who were poor metabolisers of debrisoquine in comparison with the four extensive metabolisers. Following daily oral doses of 50 mg three times a day to eight subjects, plasma concentrations of 0.10–0.24 mg/L (mean 0.18) were reported 2 h after a dose. Plasma half-life of phenformin is 10–15 h. Phenformin protein binding in plasma is about 12–20%.
By September 2014, Houthis were said to control parts of the Yemeni capital, Sanaa, including government buildings and a radio station. While Houthi control expanded to the rest of Sanaa, as well as other towns such as Rada', this control was strongly challenged by Al-Qaeda. The Gulf States believed that the Houthis had accepted aid from Iran while Saudi Arabia was aiding their Yemeni rivals. On 20 January 2015, Houthi rebels seized the presidential palace in the capital. President Abdrabbuh Mansur Hadi was in the presidential palace during the takeover but was not harmed. The movement officially took control of the Yemeni government on 6 February, dissolving parliament and declaring its Revolutionary Committee to be the acting authority in Yemen. On 20 March the al-Badr and al-Hashoosh mosques came under suicide attack during midday prayers, and the Islamic State quickly claimed responsibility. The blasts killed 142 Houthi worshippers and wounded more than 351, making it the deadliest terrorist attack in Yemen's history. On 27 March 2015, in response to perceived Houthi threats to Sunni factions in the region, Saudi Arabia along with Bahrain, Qatar, Kuwait, UAE, Egypt, Jordan, Morocco, and Sudan led a gulf coalition airstrike in Yemen. The military coalition included the United States which helped in planning of airstrikes, as well as logistical and intelligence support.
== Notable ascents == 1953 2nd ascent Yosemite Point Buttress. (With Royal Robbins) 1953 2nd ascent North Face Sentinel Rock. (With Royal Robbins and Don Wilson) 1953 Palisades Traverse Thunderbolt Peak to Mount Sill via North Palisade. (With Gary Hemming) 1954 5th ascent Lost Arrow Spire. (With Wayne Merry) 1955 3rd ascent Lost Arrow Chimney. (With Charles Wilts and Don Wilson) 1956 1st ascent Spider Rock, Canyon de Chelly National Monument, AZ, USA, March 30. (With Mark Powell and Don Wilson) 1956 1st ascent East Buttress of Middle Cathedral Rock, Yosemite National Park, CA, USA, June 16. (With Mark Powell and Don Wilson) 1956 5th ascent Castle Rock Spire. (With Charles Wilts) 1956 1st ascent Cleopatra's Needle, Valley of the Thundering Water, NM, USA, September 6. (With Mark Powell and Don Wilson) 1957 1st ascent The Step, Tahquitz Idyllwild, CA, USA, May 18. (With Royal Robbins) 1957 1st ascent Totem Pole, Monument Valley, AZ, USA. June 13. (With Bill Feuerer, Mark Powell, and Don Wilson) 1957 1st ascent Northwest Face of Half Dome, Yosemite, CA, USA, June 23–27. First grade VI climb in America. (With Mike Sherrick and Royal Robbins)
== History == Dextromoramide was discovered and patented in 1956 by Paul Janssen at Janssen Pharmaceuticals, who also discovered fentanyl, another important synthetic opioid, widely used to treat pain and in combination with other drugs as an anaesthetic, as well as haloperidol, piritramide, the loperamide-diphenoxylate series and other important drugs. Dextromoramide was much favoured by drug users in Australia in the 1970s and the United Kingdom. It has the main proprietary name of Palfium amongst others, though as of mid-2004 the drug was discontinued in the UK due to limited supplies of precursor chemicals. Although this is true, it is believed there was an approximate one year shortage of Dextromoramide and the real reason that Palfium was not put back into production for the UK market is because of how addictive and potent it is as an oral painkiller. Dependence liability is similar to morphine, but with a less severe withdrawal syndrome. The only European countries that now use the brand Palfium are the Netherlands, Ireland and Luxembourg. It is presumably able to be imported into other Schengen zone countries under Title 76 of said treaty coming into force in 2002. It is a Schedule I Narcotic controlled substance in the United States, with a DEA ACSCN of 9613 and an annual aggregate manufacturing quota of zero as of 2013, and had been out of use in the United States for around a decade when the new Controlled Substances Act 1970 was promulgated. The salts of dextromoramide in use are the hydrochloride (free base conversion ratio 0.915) and tartrate (0.724).
Distribution in pharmacology is a branch of pharmacokinetics which describes the reversible transfer of a drug from one location to another within the body. Once a drug enters into systemic circulation by absorption or direct administration, it must be distributed into interstitial and intracellular fluids. Each organ or tissue can receive different doses of the drug and the drug can remain in the different organs or tissues for a varying amount of time. The distribution of a drug between tissues is dependent on vascular permeability, regional blood flow, cardiac output and perfusion rate of the tissue and the ability of the drug to bind tissue and plasma proteins and its lipid solubility. pH partition plays a major role as well. The drug is easily distributed in highly perfused organs such as the liver, heart and kidney. It is distributed in small quantities through less perfused tissues like muscle, fat and peripheral organs. The drug can be moved from the plasma to the tissue until the equilibrium is established (for unbound drug present in plasma). The concept of compartmentalization of an organism must be considered when discussing a drug's distribution. This concept is used in pharmacokinetic modelling.
Sources: en.wikipedia.org
==== Benchmark report ==== The E.S.PKU benchmark report assesses the differences in care across Europe and provides a starting point for the E.S.PKU to improve any gaps in care that have been identified. In consequence, the delegates decided that action is required to improve this situation. The report was presented at the European Parliament. To underline this effort, the consensus paper was written.
==== Abhidharma interpretations ==== Prayudh Payutto notes that in Buddhaghosa's Sammohavinodani, a commentary to the Vibhaṅga, the principle of dependent origination is explained as occurring entirely within the space of one mind moment. Furthermore, according to Payutto, there is material in the Vibhaṅga which discusses both models, the three lifetimes model (at Vibh.147) and the one mind moment model. Similarly, Cox notes that the Sarvastivadin Vijñānakāya contains two interpretations of dependent origination, one which explains the 12 nidanas as functioning in a single moment as a way to account for ordinary experience and another interpretation that understands the 12 nidanas as arising sequentially, emphasizing their role in the functioning of rebirth and karma. Wayman notes that an interpretation referring to mental processes (referred to as dependent origination with a transient character) can also be found in northern sources, such as the Jñānaprasthāna, the Arthaviniscaya-tika and the Abhidharmakosa (AKB.III.24d). The Jñānaprasthāna, explains the nidanas with the example of the act of killing. Ignorance leads to the motivation to kill, which is acted on through consciousness, name and form and so on. This leads to mental karma being generated (bhava) which leads to the movement of the hand to kill (birth). The different interpretations of dependent origination as understood in the northern tradition can be found in the Abhidharmakosa, which outlines three models of the twelve nidanas:
On 27 October, the Catalan parliament voted in a secret ballot to unilaterally declare independence from Spain, with most deputies of the opposition boycotting a vote considered illegal for violating the decisions of the Constitutional Court of Spain, as the lawyers of the Parliament of Catalonia warned. As a result, the government of Spain invoked the Constitution to remove the regional authorities and enforce direct rule the next day, with a regional election being subsequently called for 21 December 2017 to elect a new Parliament of Catalonia. Puigdemont and part of his cabinet fled to Belgium after being ousted, as the Spanish Attorney General pressed for charges of sedition, rebellion and misuse of public funds against them. The trial of Catalonia independence leaders began on 12 February 2019 in the Supreme Court of Spain, in which 12 people were tried, including the previous vice president Oriol Junqueras of the regional government and most of the cabinet as well as political activists Jordi Sànchez and Jordi Cuixart and the former speaker of the Parliament of Catalonia Carme Forcadell. Nine of the 12 accused received prison sentences for the crimes of sedition; of them, four were also found guilty of misuse of public funds. Their sentences ranged from 9 to 13 years. The remaining three accused were found guilty of disobedience and were sentenced to pay a fine but received no prison term. The court dismissed the charges of rebellion. The verdict delivered by the Supreme Court sparked multiple protests across the region.
The half-life, t1/2, is the time taken for the activity of a given amount of a radioactive substance to decay to half of its initial value. The decay constant, λ "lambda", the reciprocal of the mean lifetime (in s−1), sometimes referred to as simply decay rate. The mean lifetime, τ "tau", the average lifetime (1/e life) of a radioactive particle before decay. Although these are constants, they are associated with the statistical behavior of populations of atoms. In consequence, predictions using these constants are less accurate for minuscule samples of atoms. In principle a half-life, a third-life, or even a (1/√2)-life, could be used in exactly the same way as half-life; but the mean life and half-life t1/2 have been adopted as standard times associated with exponential decay. Those parameters can be related to the following time-dependent parameters:
Due to decreased levels of androgens and/or neurosteroids, 5α-reductase inhibitors may slightly increase the risk of depression (~2.0% incidence). There are reports that a small percentage of men may experience persistent sexual dysfunction and adverse mood changes even after discontinuation of 5α-reductase inhibitors. Some of the possible side effects of 5α-reductase inhibitors in men, such as gynecomastia and sexual dysfunction, are actually welcome changes for many transgender women. In any case, caution may be warranted in using 5α-reductase inhibitors in transgender women, as this group is already at a high risk for depression and suicidality.
Sources: en.wikipedia.org
=== Theatres === Bromley has a number of theatres in the borough, in the town centre there are three, a professional, the Churchill Theatre, an amateur, the Bromley Little Theatre (close to Bromley North railway station) and an outdoor amphitheatre located in "Church House Gardens" behind the Churchill Theatre. The Churchill Theatre was opened on 19 July 1977 by the Prince of Wales, and seats 781. It is run on a contract currently held by HQ Theatres Ltd acting as both a receiving and producing house, with productions often transferring to the West End or touring nationally. Recent tours have included: An Inspector Calls (2024) and Fawlty Towers (2025).
=== Dust explosions === Pyrite oxidation is sufficiently exothermic that underground coal mines in high-sulfur coal seams have occasionally had serious problems with spontaneous combustion. The solution is the use of buffer blasting and the use of various sealing or cladding agents to hermetically seal the mined-out areas to exclude oxygen. In modern coal mines, limestone dust is sprayed onto the exposed coal surfaces to reduce the hazard of dust explosions. This has the secondary benefit of neutralizing the acid released by pyrite oxidation and therefore slowing the oxidation cycle described above, thus reducing the likelihood of spontaneous combustion. In the long term, however, oxidation continues, and the hydrated sulfates formed may exert crystallization pressure that can expand cracks in the rock and lead eventually to roof fall.
=== Travel distances === Teams participating in the 2026 World Cup had to travel an average of 5,146 total miles (8,281.7 km) between venues during the tournament. For the 2014 tournament in Brazil, the average distance was 7,054 miles (11,352.2 km), while teams playing in the 2018 tournament in Russia traveled an average of 5,441 miles (8,756.4 km).
He developed a method for chemical modification of the GLA residues in 1982 and studied it using various metal ims and prothrombin fragments binding to phospholipid surfaces. These studies were recognized in Hiskey's National Heart, Lung and Blood Institute's Merit Award for the period 1986 to 1996. The study was extended to include various models containing tris-phosphates and peptides containing several GLA residues. Hiskey's interest in peptide synthesis resulted in membership on the Organization Committee of the American Peptide Symposium from 1978 to 1983, as well as from 1988 to 1990, and co-chairman of the 1982 Gordon Research Conference on the Chemistry and Biology of Peptides. Hiskey also received and accepted an invitation to visit Japan as a Japan Society for the Promotion of Science Fellow as a result of his work on peptide synthesis. Finally, the American Peptide Society presented Hiskey with the Society's Annual Award in June 1996. In that same year, Hiskey retired from the University of North Carolina as Alumni Distinguished Professor Emeritus.
Sources: en.wikipedia.org
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.
No peptide with this exact sequence has been identified as an endogenous substance. It is a laboratory-designed analog of tuftsin, a naturally occurring immunomodulatory tetrapeptide. The Pro-Gly-Pro extension has no known natural source.
Proline introduces conformational constraints that make a peptide less accessible to common peptidases. This is a standard stabilization strategy in peptide design. The added residues also increase the distance between the active tuftsin portion and typical cleavage sites.
Dry powder is best kept sealed, protected from light, and held at minus 20 degrees Celsius or below. Desiccant packaging helps limit moisture uptake because the material is hygroscopic. A sealed vial should be allowed to equilibrate to room temperature before opening to reduce condensation.