The short version of Intranasal delivery fits in a sentence. The long version — which is the one that helps — is below.
This page was last updated on 2026-07-01 and is reviewed periodically as new material appears.
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.
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.
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.
| Property | Value | Notes |
|---|---|---|
| Appearance | White to off-white powder | Lyophilised solid form |
| Solubility class | Freely soluble in water | Hydrophilic heptapeptide |
| Dry storage temperature | -20 degrees Celsius or lower | Sealed, desiccated, protected from light |
| Solution storage | 2 to 8 degrees Celsius short term | Avoid repeated freeze-thaw cycles |
| Common identification method | Reversed-phase HPLC with mass spectrometry | Confirms purity and molecular mass |
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.
Published clinical work is concentrated in Russian-language journals and generally involves small samples without independent replication. Systematic reviews in English note the shortage of randomised, placebo-controlled trials and the difficulty of verifying methods from translated reports. Outcome measures vary between studies, which complicates pooling of results. Interest in the compound as a cognitive or anxiolytic agent therefore rests on a thinner evidence base than the volume of citations suggests. Replication in well-powered trials with preregistered endpoints would be needed before firm conclusions about efficacy can be drawn.
Proposed mechanisms centre on the GABAergic system. Animal and tissue studies report changes in GABA-A receptor expression and reduced activity of GABA transaminase, the enzyme that degrades GABA. Effects on monoamine turnover, including serotonin and dopamine pathways, are also described, and a separate line of work links the peptide to increased expression of brain-derived neurotrophic factor in hippocampal tissue. Most of these findings come from rodent models and cell preparations. How the individual observations combine into a single coherent mode of action is not settled.
Pharmacokinetic data are sparse and largely derived from animal work. After intranasal administration the peptide appears in plasma within minutes, and reported half-lives are short, on the order of minutes to tens of minutes. Degradation proceeds through ordinary proteolytic cleavage into constituent amino acids and smaller fragments. Direct evidence that intact Selank reaches brain tissue in meaningful amounts is limited, and the extent of blood-brain barrier penetration is debated. Some authors argue that fragments, not the parent peptide, carry much of the observed activity.
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.
Regulatory treatment varies by jurisdiction. In Russia the compound is a registered prescription product, while in the European Union and the United States it is generally handled as a research chemical without a marketing authorization. Suppliers therefore operate outside pharmaceutical oversight, and buyers rely on supplier documentation for purity and identity claims. Chain of custody and third-party testing are the main verification tools. Analysts note that the absence of a pharmacopoeial monograph for research-grade material limits standardization across vendors.
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.
Characterization of Selank in a laboratory setting relies on standard peptide methods. Reverse-phase high-performance liquid chromatography separates the target from related impurities and provides a purity figure, commonly reported as 95 percent or higher. Mass spectrometry, typically electrospray ionization or matrix-assisted laser desorption, confirms the molecular mass and helps detect truncation or modification. Amino acid analysis can verify composition when a sequence-level check is needed. These techniques together establish identity and purity for a given lot.
Lyophilized Selank, the dry powder form, is generally stored frozen at minus 20 degrees Celsius or colder for long-term keeping. The solid is hygroscopic and should stay sealed, dry, and protected from light. Once dissolved, the peptide is less stable and is usually held refrigerated at 2 to 8 degrees Celsius for short periods. Repeated freezing and thawing is avoided because it can promote aggregation and loss of activity. Buffers and pH choice also affect how long a solution remains usable.
Applications in the musculoskeletal system include spinal imaging, assessment of joint disease, and soft tissue tumors. MRI techniques can also be used for diagnostic imaging of systemic muscle diseases including genetic muscle diseases. Swallowing movements of the throat and esophagus can cause motion artifacts over the imaged spine. Therefore, a saturation pulse applied over this region can help to avoid these artifacts. Motion artifacts arising due to the pumping of the heart can be reduced by timing the MRI pulse according to heart cycles. Blood vessel flow artifacts can be reduced by applying saturation pulses above and below the region of interest.
TAP is a heterodimeric complex, consisting of TAP1 (ABCB2) and TAP2 (ABCB3) members of the ABC transporter superfamily. The common feature of all ABC transporters is their organization: 1) into two transmembrane domains (TMDs) and 2) into two nucleotide-binding domains (NBDs). Both intramolecular domains are coupled to each other and when ATP binding is in progress, conformational changes in the TMDs allow proteasomal degradation products to move across the membrane. TAP recognizes and transports the antigen peptides produced in the cytosol straight into the ER, while tapasin recognizes the kind of peptides that have the ability to form stable complexes with MHC-I. This process is known as peptide proofreading or editing. Peptides selected through proofreading improve MHC-I stability; tapasin also contributes to the editing of immunogenic peptide epitopes. However, only lately it was proven via biochemical, biophysical, and structural studies that a key function in adaptive immunity, the catalytic mechanism of peptide proofreading, is performed by tapasin and TAPBPR (TAP-binding protein-related, a tapasin homologue).
Many skin conditions affect the human integumentary system—the organ system covering the entire surface of the body and composed of skin, hair, nails, and related muscles and glands. The major function of this system is as a barrier against the external environment. The skin weighs an average of four kilograms, covers an area of two square metres, and is made of three distinct layers: the epidermis, dermis, and subcutaneous tissue. The two main types of human skin are: glabrous skin, the hairless skin on the palms and soles (also referred to as the "palmoplantar" surfaces), and hair-bearing skin. Within the latter type, the hairs occur in structures called pilosebaceous units, each with hair follicle, sebaceous gland, and associated arrector pili muscle. In the embryo, the epidermis, hair, and glands form from the ectoderm, which is chemically influenced by the underlying mesoderm that forms the dermis and subcutaneous tissues. The epidermis is the most superficial layer of skin, a squamous epithelium with several strata: the stratum corneum, stratum lucidum, stratum granulosum, stratum spinosum, and stratum basale. Nourishment is provided to these layers by diffusion from the dermis since the epidermis is without direct blood supply. The epidermis contains four cell types: keratinocytes, melanocytes, Langerhans cells, and Merkel cells. Of these, keratinocytes are the major component, constituting roughly 95 percent of the epidermis.
Erectile dysfunction (ED), also referred to as impotence, is a form of sexual dysfunction in males characterized by the persistent or recurring inability to achieve or maintain a penile erection with sufficient rigidity and duration for satisfactory sexual activity. It is the most common sexual problem in males and can cause psychological distress due to its impact on self-image and sexual relationships. The term erectile dysfunction does not encompass other erection-related disorders, such as priapism. The majority of ED cases are attributed to physical risk factors and predictive factors. These factors can be categorized as vascular, neurological, local penile, hormonal, and drug-induced. Notable predictors of ED include aging, cardiovascular disease, diabetes mellitus, high blood pressure, obesity, abnormal lipid levels in the blood, hypogonadism, smoking, depression, and medication use. Approximately 10% of cases are linked to psychosocial factors, encompassing conditions such as depression, stress, and problems within relationships. ED is reported in 18% of males aged 50 to 59 years, and 37% in males aged 70 to 75. Treatment of ED encompasses addressing the underlying causes, lifestyle modification, and addressing psychosocial issues. In many instances, medication-based therapies are used, specifically PDE5 inhibitors such as sildenafil. These drugs function by dilating blood vessels, facilitating increased blood flow into the spongy tissue of the penis, analogous to opening a valve wider to enhance water flow in a fire hose.
=== „Gott ist schön“ (Dissertation 1998) === A parallel (including excursions into the scholarly realm) is discernable here with Kermani's narratively oriented 1999 dissertation „Gott ist schön“ (God is Beautiful). The dissertation, after all, investigates the (musical) aesthetics of the Koran and contains a subchapter entitled “Those Killed by the Koran“.
Sources: en.wikipedia.org
== Sector quadrupole == A sector instrument can be combined with a collision quadrupole and quadrupole mass analyzer to form a hybrid instrument. A BEqQ configuration with a magnetic sector (B), electric sector (E), collision quadrupole (q) and m/z selection quadrupole (Q) have been constructed and an instrument with two electric sectors (BEEQ) has been described.
== Early life and education == Francisco "Kiko" Tiu Laurel Jr. was born to Francisco Sr. and Bella Tiu Laurel. As a teenager, Laurel was involved in the Frabelle Fishing Company, and became a full-time employee at 20, where he started in the Engineering department before moving into sales and leadership. He did not finish a college degree, saying that he had dropped out at the age of 19 to find a job that would support his first child.
The latter earned DiCaprio a Silver Bear for Best Actor at the 1997 Berlin International Film Festival. He then portrayed a young man who has been committed to a mental asylum in Marvin's Room (1996), a family drama about two estranged sisters, played by Meryl Streep and Diane Keaton, who are reunited through tragedy. He played Hank, the troubled son of Streep's character. Lisa Schwarzbaum of Entertainment Weekly praised "the deeply gifted DiCaprio" for holding his own against veteran actresses Keaton and Streep, describing the three as "full-bodied and so powerfully affecting that you're carried along on the pleasure of being in the presence of their extraordinary talent".
Birch wood is a type of wood of the birch. Birch wood is pale yellow-brown wood having a close, straight grain and uniform texture that finishes to a smooth surface. Sometimes it is dyed to imitate mahogany. This type of wood is used for among others firewood, turnery, furniture, cabinetry, tool handles, hoops, plywood, flooring and shoe heels.
=== Hunger and malnutrition === Hunger is increasing, and more so in countries affected by conflict, climate extremes and economic downturns, and with high income inequality. The magnitude and severity of food crises also worsened in 2020 as protracted conflict, the economic fallout of the COVID-19 pandemic and weather extremes exacerbated pre-existing fragilities. Economic downturns in 2020, including those resulting from COVID-19 restrictions, delivered the hardest blow in decades to those suffering from hunger, increasing the number of undernourished people by 118 million in 2020 alone and illustrating the devastating impact of a shock that occurs alongside existing vulnerabilities. According to Béné et al. (2020), there is little evidence of reduced food supply (beyond initial disruptions due to panic buying), which may be attributable to government exemptions for the agrifood sector. However, lockdowns and other mobility restrictions drastically reduced the movement of people and goods, which impacted livelihoods. Loss of income and purchasing power sharply reduced the food security and nutrition of billions of people, particularly in low-income and middle-income countries. Families were forced to shift consumption to cheaper, less nutritious foods at a time when they needed to protect and strengthen their immune system. Reduced access to nutritious food and a shift to low-quality and energy-dense diets triggered by the economic impacts of the COVID-19 pandemic, also risk increasing the levels of overweight and obesity in almost all regions of the world.
Sources: en.wikipedia.org
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.
Reversed-phase HPLC establishes purity, while mass spectrometry confirms the expected molecular mass. Sequence confirmation may use tandem mass spectrometry or peptide mapping. A certificate of analysis typically reports these results alongside the analytical method applied.
In Russia it is a registered medicine available by prescription. In many other countries it is not approved for human use and is supplied only as a research chemical. Import and possession rules differ by jurisdiction, and buyers are responsible for checking local requirements.
Selank is a synthetic seven-amino-acid peptide modeled on tuftsin, a fragment of the immunoglobulin G heavy chain. It was designed in Russia to combine anxiolytic and immunomodulatory properties in one molecule.