lyophilization raises a handful of sensible questions. This page answers them in order, starting with the fundamentals and moving to applications.
This page was last updated on 2025-12-02 and is reviewed periodically as new material appears.
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.
Tuftsin, the parent structure, is a naturally occurring immunomodulatory tetrapeptide released from the Fc region of immunoglobulin G by spleen enzymes. Selank extends this four-residue sequence with three additional amino acids. The stated rationale is that the added tail slows enzymatic breakdown and may influence receptor interactions. How the full heptapeptide behaves at the molecular level is not firmly established, and proposed mechanisms often involve indirect modulation of neurotransmitter or immune signaling rather than a single defined target.
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.
| 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 |
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.
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.
== External links == Overview of all the structural information available in the PDB for UniProt: Q04760 (Human Lactoylglutathione lyase) at the PDBe-KB. Overview of all the structural information available in the PDB for UniProt: Q9CPU0 (Mouse Lactoylglutathione lyase) at the PDBe-KB.
== External links == The MEROPS online database for peptidases and their inhibitors: Serine Peptidase Archived 2017-04-04 at the Wayback Machine Serine Proteases site at Saint Louis University (SLU) Serine+proteases at the U.S. National Library of Medicine Medical Subject Headings (MeSH)
== Etymology == The word slave was borrowed into Middle English through the Old French esclave which ultimately derives from Byzantine Greek σκλάβος (sklábos) or ἐσκλαβῆνος (esklabḗnos). According to the widespread view, which has been known since the 18th century, the Byzantine Σκλάβινοι (Sklábinoi), Ἐσκλαβηνοί (Esklabēnoí), borrowed from a Slavic tribe self-name *Slověne, turned into σκλάβος, ἐσκλαβῆνος (Late Latin sclāvus) in the meaning 'prisoner of war slave', 'slave' in the 8th/9th century, because they often became captured and enslaved. However this version has been disputed since the 19th century. An alternative contemporary hypothesis suggests that Medieval Latin sclāvus via *scylāvus derives from Byzantine σκυλάω (skūláō, skyláō) or σκυλεύω (skūleúō, skyleúō) with the meaning "to strip the enemy (killed in a battle)" or "to make booty / extract spoils of war". This version has been criticized as well.
=== Scandinavian === Scandinavian American Fraternity - Founded in 1893. Membership was open to Christians of Scandinavian descent who were of good moral character. The by-laws prohibited discussing religious or political subjects. There was a ritualistic element to the fraternity, including a lodge altar and a burial service, that was criticized by Christian Cynosure as being "heathen", though prominent churchmen such as the Rev. P. R. Syrdal of the Norwegian Lutheran Church of America were active members who defended the organization. Grand Lodge headquarters at Eau Claire, Wisconsin. In 1923 it had 8,085 benefit members and 71 social members spread across Wisconsin, Minnesota, Illinois, and North Dakota. Scandinavian Fraternity of America - Founded in 1915 as the consolidation of three other groups including the Scandinavian Brotherhood of America, which had been founded in 1894. Membership began to decline in the 1980s, dropping from 37 lodges in 1983 to 28 in 1985. In 1991 it was reported to have only 2,500 members, a number repeated in 1995.
Flucloxacillin is a narrow-spectrum antibiotic belonging to the penicillin group of antibiotics. It works by breaking down the bacterial cell wall. Like other β-lactam antibiotics, flucloxacillin acts by inhibiting the synthesis of bacterial cell walls. It inhibits cross-linkage between the linear peptidoglycan polymer chains that make up a major component of the cell wall of Gram-positive bacteria. Flucloxacillin is more acid-stable than many other penicillins and can be given orally, in addition to parenteral routes. However, like methicillin, it is less potent than benzylpenicillin against non-β-lactamase-producing Gram-positive bacteria. Flucloxacillin has similar pharmacokinetics, antibacterial activity, and indications to dicloxacillin, and the two agents are considered interchangeable. It is reported to have higher, though rare, incidence of severe hepatic adverse effects than dicloxacillin, but a lower incidence of renal adverse effects.
Sources: en.wikipedia.org
==== Non-nucleoside phosphoramidites ==== Non-nucleoside phosphoramidites are the phosphoramidite reagents designed to introduce various functionalities at the termini of synthetic oligonucleotides or between nucleotide residues in the middle of the sequence. In order to be introduced inside the sequence, a non-nucleosidic modifier has to possess at least two hydroxy groups, one of which is often protected with the DMT group while the other bears the reactive phosphoramidite moiety. Non-nucleosidic phosphoramidites are used to introduce desired groups that are not available in natural nucleosides or that can be introduced more readily using simpler chemical designs. A very short selection of commercial phosphoramidite reagents is shown in Scheme for the demonstration of the available structural and functional diversity. These reagents serve for the attachment of 5'-terminal phosphate (1), NH2 (2), SH (3), aldehydo (4), and carboxylic groups (5), CC triple bonds (6), non-radioactive labels and quenchers (exemplified by 6-FAM amidite 7 for the attachment of fluorescein and dabcyl amidite 8, respectively), hydrophilic and hydrophobic modifiers (exemplified by hexaethyleneglycol amidite 9 and cholesterol amidite 10, respectively), and biotin amidite 11.
Bromazepam is commonly involved in drug overdoses. A severe bromazepam benzodiazepine overdose may result in an alpha pattern coma type. The toxicity of bromazepam in overdosage increases when combined with other CNS depressant drugs such as alcohol or sedative hypnotic drugs. Similarly to other benzodiazepines however, being a positive modulator of certain neuroreceptors and not an agonist, the product has reduced overdose potential compared to older products of the barbiturate class. Its consumption alone is very seldom fatal in healthy adults. Bromazepam was in 2005 the most common benzodiazepine involved in intentional overdoses in France. Bromazepam has also been responsible for accidental poisonings in companion animals. A review of benzodiazepine poisonings in cats and dogs from 1991 to 1994 found bromazepam to be responsible for significantly more poisonings than any other benzodiazepine.
as a vasodilator in severe Raynaud's phenomenon or ischemia of a limb; in pulmonary hypertension. in primary pulmonary hypertension (PPH) The production of prostacyclin is inhibited by the action of NSAIDs on cyclooxygenase enzymes COX1 and COX2. These convert arachidonic acid to prostaglandin H2 (PGH2), the immediate precursor of prostacyclin. Since thromboxane (an eicosanoid stimulator of platelet aggregation) is also downstream of COX enzymes, one might think that the effect of NSAIDs would act to balance. However, prostacyclin concentrations recover much faster than thromboxane levels, so aspirin administration initially has little to no effect but eventually prevents platelet aggregation (the effect of prostaglandins predominates as they are regenerated). This is explained by understanding the cells that produce each molecule, TXA2 and PGI2. Since PGI2 is primarily produced in a nucleated endothelial cell, the COX inhibition by NSAID can be overcome with time by increased COX gene activation and subsequent production of more COX enzymes to catalyze the formation of PGI2. In contrast, TXA2 is released primarily by anucleated platelets, which are unable to respond to NSAID COX inhibition with additional transcription of the COX gene because they lack DNA material necessary to perform such a task. This allows NSAIDs to result in PGI2 dominance that promotes circulation and retards thrombosis. In patients with pulmonary hypertension, inhaled epoprostenol reduces pulmonary pressure, and improves right ventricular stroke volume in patients undergoing cardiac surgery.
Sulfuric acid is a colorless oily liquid, and has a vapor pressure of <0.001 mmHg at 25 °C and 1 mmHg at 145.8 °C, and 98% sulfuric acid has a vapor pressure of <1 mmHg at 40 °C. In the solid state, sulfuric acid is a molecular solid that forms monoclinic crystals with nearly trigonal lattice parameters. The structure consists of layers parallel to the (010) plane, in which each molecule is connected by hydrogen bonds to two others. Hydrates H2SO4·nH2O are known for n = 1, 2, 3, 4, 6.5, and 8, although most intermediate hydrates are stable against disproportionation.
Sources: en.wikipedia.org
=== Reference levels in normal pregnancy === The hCG levels grow exponentially after conception and implantation. hCG levels typically peak around weeks 8-11 of pregnancy and are generally higher in the first trimester compared to the second trimester. The following is a list of serum hCG levels: LMP is the last menstrual period dated from the first day of the last menstrual period
The metabolism of bupropion also seems to follow biphasic pharmacokinetics: the redistribution alpha phase with half-life of about 1 hour precedes the metabolism beta phase of about 12–30 hours. This might explain why abuse is unfeasible due to a short "high", as well as support the use of extended-release formulas to maintain a consistent concentration of bupropion. The metabolism of bupropion is highly species-dependent. As an example, oral bupropion results in hydroxybupropion levels that are 16-fold higher than those of bupropion itself in humans, whereas in rats, oral bupropion results in levels of bupropion that are 3.4-fold higher than those of hydroxybupropion. The species-dependent metabolism of bupropion is thought to be involved in species differences in its pharmacodynamic effects. For example, bupropion produces psychostimulant-like and reinforcing effects in rodents, whereas oral bupropion at therapeutic doses in humans seems to have much less or no potential for such effects. Bupropion has also been found to produce self-administration when given intravenously in monkeys.
ZMapp was first used during the 2014 West Africa Ebola Virus outbreak, having not previously undergone any human clinical trials to determine its efficacy or potential risks. By October 2014, the United States Food and Drug Administration had approved the use of several experimental drugs, including ZMapp, to be used on patients infected with Ebola virus. The use of such drugs during the epidemic was also deemed ethical by the World Health Organization (WHO). In 2014, a limited supply of ZMapp was used to treat 7 individuals infected with the Ebola virus; of these 2 died. The outcome is not considered to be statistically significant. Mapp announced in August 2014, that supplies of ZMapp had been exhausted.
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.
Selank is a synthetic peptide made of seven amino acids. It is modeled on tuftsin, a natural tetrapeptide, with an added three-residue tail. It is not a small-molecule drug.