Everything below concerns reverse-phase HPLC. We keep the language plain, cite what the science says, and separate well-supported claims from open questions.
Updated 2025-12-15. Numbers and descriptions here follow the published literature rather than marketing material.
Peptide bonds are vulnerable to protease attack, and Selank is no exception. Measured half-life in serum is short, on the order of minutes in several reports, which explains why intranasal administration is the common route described in the literature. Absorption across the nasal mucosa partially bypasses first-pass hepatic metabolism. Quantitative data on human bioavailability remain limited and are difficult to compare across studies.
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.
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.
| Property | Value | Notes |
|---|---|---|
| Dry storage temperature | -20 C or below | Sealed, desiccated, protected from light |
| Solution stability | Hours to days at 2-8 C | Depends on buffer and microbial load |
| Preferred pH range | Near neutral to slightly acidic | Alkaline pH accelerates hydrolysis |
| Main degradation routes | Hydrolysis and deamidation | No cysteine or methionine in sequence |
| Identity confirmation | Electrospray mass spectrometry | Observed mass compared with 751.9 Da |
Selank is a synthetic heptapeptide with the sequence Thr-Lys-Pro-Arg-Pro-Gly-Pro. It was designed at the Institute of Molecular Genetics of the Russian Academy of Sciences as a structural analogue of tuftsin, a naturally occurring tetrapeptide fragment of the immunoglobulin heavy chain. The added Pro-Gly-Pro tail was intended to slow enzymatic degradation and extend biological activity. In Russia it is registered as an anxiolytic nasal preparation, while regulators elsewhere have not approved it for clinical use.
Proposed mechanisms centre on modulation of the GABAergic system, with reports of altered expression of genes related to GABA-A receptor subunits and changed monoamine turnover. Some studies describe inhibition of enkephalinase, the enzyme that degrades endogenous enkephalins, which may prolong opioid peptide signalling. Effects on brain-derived neurotrophic factor and on cytokine expression have also been reported. These findings come largely from animal models and small human studies, and the precise primary target remains unresolved.
Purity assessment relies mainly on reverse-phase high-performance liquid chromatography with ultraviolet detection. Because the peptide lacks a strong chromophore, detection often uses backbone absorbance near 214 nm. Identity is confirmed by mass spectrometry, typically electrospray ionization or matrix-assisted laser desorption, comparing the measured mass against the expected value. Amino acid analysis can verify composition after acid hydrolysis. Diastereomer content and residual counterions are reported less often, although both can influence biological assays.
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.
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.
=== Vagina === Between the years 2005 and 2008, four women with vaginal hypoplasia due to Müllerian agenesis were given regenerated vaginas. Up to eight years after the transplants, all organs have normal function and structure.
== External links == "WISP wiki page". "Sensor Systems Lab WISP description". Archived from the original on 2018-10-11. Retrieved 2018-10-11. Alanson P. Sample; Daniel J Yeager; Pauline S Powledge; Alexander V Mamishev; Joshua R Smith (2018-06-06). "Design of an RFID-based battery-free programmable sensing platform". IEEE Transactions on Instrumentation and Measurement. 57 (11): 2608–2615. M. Segev-Bar; N. Bachar; Y.Wolf; B. Ukrainsky; L. Sarraf; H. Haick (Dec 13, 2016). "Multi‐Parametric Sensing Platforms Based on Nanoparticles". Advanced Materials Technologies. 2 (1) 1600206. doi:10.1002/admt.201600206. S2CID 63385571. [...] potentially to differentiate between the different signals. They have advantages in fields that include wearable systems, humanoid robotics, structural health monitoring and precision agriculture, [...]
=== Food supplement === The valuable cannabinoids, proteins, vitamins, minerals, polyphenols, and poly-unsaturated fatty acids are useful to prevent deficiencies and aid muscle growth. Athletes for instance use protein powder made from hemp. Hemp juice offers a natural alternative to the industrially produced hemp protein. Even the dietary fibers in the press remnants can be used for food supplements if fermented. Finely ground hemp press remnants can substitute some portion of flour in bread recipes with yeast.
Sources: en.wikipedia.org
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Carbohydrate metabolism is the whole of the biochemical processes responsible for the metabolic formation, breakdown, and interconversion of carbohydrates in living organisms. Carbohydrates are central to many essential metabolic pathways. Plants synthesize carbohydrates from carbon dioxide and water through photosynthesis, allowing them to store energy absorbed from sunlight internally. When animals and fungi consume plants, they use cellular respiration to break down these stored carbohydrates to make energy available to cells. Both animals and plants temporarily store the released energy in the form of high-energy molecules, such as adenosine triphosphate (ATP), for use in various cellular processes. While carbohydrates are essential to human biological processes, consuming them is not essential for humans. There are healthy human populations that do not consume carbohydrates. In humans, carbohydrates are available directly from consumption, from carbohydrate storage, or by conversion from fat components including fatty acids that are either stored or consumed directly.
Hamdullah Fitrat, Taliban's deputy spokesperson, said the Pakistani forces targeted a home in Paktia's Chamkani district, killing an elder and a child, while injuring others. The area was struck again 25 minutes after the first strike when residents had gathered to rescue people. 28 villagers died in the second strike while 158 more were wounded. Hospital footage showed infants and elderly victims on stretchers. A survivor directly refuted Pakistan's claims that the targets were terrorists. Additionally, six more civilians were killed in a Giyan district village in Paktika province. Pakistani electronic jammers also downed a drone in North Waziristan. On 29 June, insurgents killed a police constable in Bannu District, while four TTP militants were also killed in an operation in the district. An explosion and fire were reported in Kabul. Six border guards were killed, nine wounded and one abducted as Pakistani Taliban militants overrun a border post in Chitral District. On 30 June, an Afghan Refugees Camp was hit in a drone strike/shootdown in Pishin District and a school was hit by a drone strike in Kila Abdullah District, Pakistan Air Force also downed a drone in Quetta. Pakistan claimed to have shot down a total of four "rudimentary" drones from Afghanistan. Afghanistan claimed that its forces successfully hit an ISKP camp in Pishin District. Border post No. 2417 in Kurram District was targeted by sniper fire killing one Pakistani FC soldier. On 1 July, an Afghan drone was shot down by Pakistani forces in Khyber District.
Sources: en.wikipedia.org
==== December ==== On 1 December, the National Guard detained 10 people, including Sheikh Raed al-Matni, Assem Abou Fakher, Ghandi Abou Fakher, Maher Falhout, Hussam Zeidan, Zeidan Zeidan and Alameddine Zeidan, clarifying that they carried out a “swift and precise” operation to arrest what it called “traitors and conspirators”. On 3 December, Sheikh Raed al-Matni's body was found with signs of torture, after being accused of having links with the Syrian government and Suleiman Abdul Baqi. The National Guard also raided al-Baqi's house, and promised a strong response. Sheikh Maher Falhout was also killed. The National Guard was reportedly behind the killings. On 8 December, the National Guard reported mortar and drone attacks by the Syrian government forces, the affected areas are: Tel Hadid, Al-Maamel road and the Kanaker area. The National Guard declared that "the hostile fire and sources of fire were extinguished and full control of the situation on the field was restored". On 15 December, the National Guard killed the poet Anwar al-Shaer, due to their criticism of the group, in Busan, Suwayda, he was taken to the Suweida National Hospital. His brother stated that "In a cowardly and treacherous operation, the martyr of the word of truth, Anwar Fawzat Al-Shaer, the free national revolutionary poet, was murdered in front of his house" and swore revenge.
== Format == A formal, distinct, and unique 6-part name is given to each term for test or observation identity. The database currently has over 71,000 observation terms that can be accessed and understood universally. Each database record includes six fields for the unique specification of each identified single test, observation, or measurement:
== Dependence and withdrawal == Nonbenzodiazepines are as addictive as benzodiazepines. Nonbenzodiazepines should not be discontinued abruptly if taken for more than a few weeks due to the risk of rebound withdrawal effects and acute withdrawal reactions, which may resemble those seen during benzodiazepine withdrawal. Treatment usually entails gradually reducing the dosage over a period of weeks or several months depending on the individual, dosage, and length of time the drug has been taken. If this approach fails, a crossover to a benzodiazepine equivalent dose of a long-acting benzodiazepine (such as chlordiazepoxide or more preferably diazepam) can be tried followed by a gradual reduction in dosage. In extreme cases and, in particular, where severe addiction and/or abuse is manifested, an inpatient detoxification may be required.<
Sources: en.wikipedia.org
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.
Hydrolysis of peptide bonds and deamidation of arginine and proline residues are the main degradation routes. Alkaline pH and higher temperatures accelerate both processes. Buffered, near-neutral solutions stored cold generally degrade more slowly than unbuffered ones.
Reverse-phase chromatography gives the clearest single view of related impurities and truncated sequences. Mass spectrometry then confirms that the main peak carries the expected mass. Neither test detects enantiomeric impurities, which require a separate chiral assay.
Intranasal administration predominates in both animal and human research because it avoids hepatic first-pass metabolism. Injectable and intraperitoneal routes appear in animal work mainly for comparison.