pharmacokinetics 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 2026-04-20 and is reviewed periodically as new material appears.
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.
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.
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.
| Property | Value | Notes |
|---|---|---|
| Chemical class | Synthetic heptapeptide | Analog of the tetrapeptide tuftsin |
| Sequence | Thr-Lys-Pro-Arg-Pro-Gly-Pro | Reported consistently across pharmacopoeial descriptions |
| Appearance | White to off-white lyophilized powder | Typical form of research-grade material |
| Solubility | Freely soluble in water | Aqueous buffers; poor in nonpolar solvents |
| Typical storage temperature | -20 degrees Celsius | Lyophilized powder; protect from moisture |
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.
Solubility behavior is a practical concern for handling. Selank dissolves readily in water and in common aqueous buffers, which simplifies preparation of working solutions. The choice of solvent, ionic strength, and pH can influence aggregation over time, particularly at higher concentrations. Aqueous solutions are typically sterile-filtered before use. Because stability depends on several variables, storage and handling notes should be treated as general guidance rather than fixed rules, and specific values are best confirmed against a certificate of analysis for each batch.
Proposed mechanisms center on modulation of the GABA system, but no single molecular target has been confirmed. Rodent studies report changes in GABA-A receptor expression and in the turnover of serotonin, dopamine, and norepinephrine in several brain regions. Increases in brain-derived neurotrophic factor and its receptor have also been described after repeated administration. These findings come largely from animal models, and the degree to which they describe human neurochemistry remains an open question. The mechanism is best characterized as multi-system and not fully resolved.
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.
Characterization of Selank in laboratory settings relies on standard peptide analytical techniques. Reverse-phase high-performance liquid chromatography separates the peptide from related impurities and degradation products, while mass spectrometry confirms molecular identity through accurate mass measurement. Amino acid analysis and peptide sequencing verify the primary structure when reference material is unavailable. Because Selank is a short chain, fragmentation-based analysis produces a diagnostic ion pattern that supports confident identification.
Peptide stability depends strongly on temperature, moisture, and pH. Lyophilized Selank is generally most stable when stored cold and dry, with freezer temperatures commonly used for long-term storage. In solution, the compound is susceptible to hydrolysis and to microbial growth if it is not handled aseptically. The C-terminal proline-rich extension appears to slow enzymatic cleavage relative to tuftsin, though quantitative degradation rates vary with the matrix and the conditions tested. Published stability data specific to Selank remain sparse.
Quality assessment of Selank samples typically combines purity determination with identity confirmation and counter-ion analysis. Purity is usually reported as a percentage by chromatographic area, with values above 95 percent often quoted for research-grade material. Water content and residual solvents are checked in lyophilized batches because they affect both stability and accurate mass determination. A reported purity figure does not by itself establish that a sample is the intended sequence, so orthogonal methods are needed to rule out sequence isomers or truncation products.
=== Cost === Irradiation is a capital-intensive technology requiring a substantial initial investment, ranging from $1 million to $5 million. In the case of large research or contract irradiation facilities, major capital costs include a radiation source, hardware (irradiator, totes and conveyors, control systems, and other auxiliary equipment), land (1 to 1.5 acres), radiation shield, and warehouse. Operating costs include salaries (for fixed and variable labor), utilities, maintenance, taxes/insurance, cobalt-60 replenishment, general utilities, and miscellaneous operating costs. Perishable food items, like fruits, vegetables and meats would still require to be handled in the cold chain, so all other supply chain costs remain the same. Food manufacturers have not embraced food irradiation because the market does not support the increased price of irradiated foods, and because of potential consumer backlash due to irradiated foods. The cost of food irradiation is influenced by dose requirements, the food's tolerance of radiation, handling conditions, i.e., packaging and stacking requirements, construction costs, financing arrangements, and other variables particular to the situation.
It has local production plants in Bologna and Florence in Italy along with other manufacturing sites in Germany, France, Switzerland, Spain, United Kingdom, U.S.A., India, Malaysia and China. More than 5,000 are employed in the company, 2,600 of those work abroad. Its annual turnover in 2016 was €1.310,55 million. Its employees number more than 5,000 (with about 2,600 outside of Italy) in 41 manufacturing sites in Italy, Germany, France, Switzerland, Spain, the UK, the US, India, Malaysia, China and Argentina. Its sales network covers more than 80 countries. The Group has around 6,000 employees, of which over 2,800 overseas, and has 45 production plants in Italy, Germany, France, Switzerland, Spain, United Kingdom, United States, India, Malaysia, China and Argentina. IMA has an extensive commercial network, which consists of 29 branches with sales and assistance services in Italy, France, Switzerland, United Kingdom, Germany, Austria, Spain, Poland, Israel, Russia, United States, India, China, Malaysia, Thailand and Brazil, representative offices in Central and Eastern European countries and more than 50 agencies covering a total of about 80 countries. In addition, in 2019, it had a turnover of 1,595.5 million euros, of which about 90% outside Italy.
=== EC 2.7.8: Transferases for other substituted phosphate groups === EC 2.7.8.1: diacylglycerol ethanolaminephosphotransferase EC 2.7.8.2: diacylglycerol cholinephosphotransferase EC 2.7.8.3: ceramide cholinephosphotransferase EC 2.7.8.4: serine ethanolaminephosphotransferase EC 2.7.8.5: CDP-diacylglycerol—glycerol-3-phosphate 1-phosphatidyltransferase EC 2.7.8.6: undecaprenyl-phosphate galactose phosphotransferase EC 2.7.8.7: holo-[acyl-carrier-protein] synthase EC 2.7.8.8: CDP-diacylglycerol—serine O-phosphatidyltransferase EC 2.7.8.9: phosphomannan mannosephosphotransferase EC 2.7.8.10: sphingosine cholinephosphotransferase EC 2.7.8.11: CDP-diacylglycerol—inositol 3-phosphatidyltransferase EC 2.7.8.12: CDP-glycerol glycerophosphotransferase EC 2.7.8.13: phospho-N-acetylmuramoyl-pentapeptide-transferase EC 2.7.8.14: CDP-ribitol ribitolphosphotransferase EC 2.7.8.15: UDP-N-acetylglucosamine—dolichyl-phosphate N-acetylglucosaminephosphotransferase EC 2.7.8.16: deleted, now included with EC 2.7.8.2 diacylglycerol cholinephosphotransferase EC 2.7.8.17: UDP-N-acetylglucosamine—lysosomal-enzyme N-acetylglucosaminephosphotransferase EC 2.7.8.18: UDP-galactose—UDP-N-acetylglucosamine galactose phosphotransferase EC 2.7.8.19: UDP-glucose—glycoprotein glucose phosphotransferase EC 2.7.8.20: phosphatidylglycerol—membrane-oligosaccharide glycerophosphotransferase EC 2.7.8.21: membrane-oligosaccharide glycerophosphotransferase EC 2.7.8.22: 1-alkenyl-2-acylglycerol choline phosphotransferase EC 2.7.8.23: carboxyvinyl-carboxyphosphonate phosphorylmutase EC 2.7.8.24: CDP-diacylglycerol—choline O-phosphatidyltransferase EC 2.7.8.25: Now EC 2.4.2.52, triphosphoribosyl-dephospho-CoA synthase EC 2.7.8.26: adenosylcobinamide-GDP ribazoletransferase EC 2.7.8.27: sphingomyelin synthase EC 2.7.8.28: 2-phospho-L-lactate transferase EC 2.7.8.29: L-serine-phosphatidylethanolamine phosphatidyltransferase EC 2.7.8.30: Now EC 2.4.2.53, undecaprenyl-phosphate 4-deoxy-4-formamido-L-arabinose transferase EC 2.7.8.31: undecaprenyl-phosphate glucose phosphotransferase EC 2.7.8.32: 3-O-α-D-mannopyranosyl-α-D-mannopyranose xylosylphosphotransferase EC 2.7.8.33: UDP-N-acetylglucosamine—undecaprenyl-phosphate N-acetylglucosaminephosphotransferase EC 2.7.8.34: CDP-L-myo-inositol myo-inositolphosphotransferase EC 2.7.8.35: UDP-N-acetylglucosamine—decaprenyl-phosphate N-acetylglucosaminephosphotransferase EC 2.7.8.36: undecaprenyl phosphate N,N′-diacetylbacillosamine 1-phosphate transferase EC 2.7.8.37: α-D-ribose 1-methylphosphonate 5-triphosphate synthase EC 2.7.8.38: archaetidylserine synthase EC 2.7.8.39: archaetidylinositol phosphate synthase EC 2.7.8.40: UDP-N-acetylgalactosamine-undecaprenyl-phosphate N-acetylgalactosaminephosphotransferase EC 2.7.8.41: cardiolipin synthase (CMP-forming) EC 2.7.8.42: Kdo2-lipid A phosphoethanolamine 7′′-transferase EC 2.7.8.43: lipid A phosphoethanolamine transferase EC 2.7.8.44: teichoic acid glycerol-phosphate primase EC 2.7.8.45: teichoic acid glycerol-phosphate transferase EC 2.7.8.46: teichoic acid ribitol-phosphate primase EC 2.7.8.47: teichoic acid ribitol-phosphate polymerase
The pharmacokinetic properties of sitagliptin and vildagliptin appear unaffected by age, sex or BMI. Clinical researches have shown that sitagliptin and vildagliptin do not have the side effects that tend to follow type 2 diabetes treatment, e.g. weight gain and hyperglycemia, but however, other side effects have been observed, including upper respiratory tract infections, sore throat and diarrhea.
==== Less frequent ==== Hb H (β4) Hb Barts (γ4) Hb O (α2βO2) Hb Bassett Hb Kansas Hb D-Punjab Hb O-Arab Hb G-Philadelphia Hb Hasharon Hb Kirklareli Hb Lepore Hb M Hb Hope Hb Pisa Hb J Hb N-Baltimore Hemoglobin Chesapeake Hemoglobin Louisville Hemoglobin Vanvitelli
Sources: en.wikipedia.org
However, the military provided him with no records of any medical discrepancies caused by actions during war. If Willie was to be diagnosed with Gulf War Illness, he would not have a course of treatment. He would have to learn to cope with the disease until a treatment becomes available in the future. Willie and his wife go to visit a Marine Veteran who was diagnosed with Gulf War Illness to be able to relate any similarities and narrow down the possibilities.
=== Cultural outlook === Irish society during this period was extremely Roman Catholic, with Roman Catholic thinkers promoting anti-capitalist, anti-communist, anti-Protestant, anti-Masonic, and antisemitic views in Irish society. Through the works of priests such as Edward Cahill, Richard Devane, and Denis Fahey, Irish society saw capitalism, individualism, communism, private banking, the promotion of alcohol, contraceptives, divorce, and abortion as the pursuits of the old 'Protestant-elite' and Jews, with their efforts combined through the Freemasons. Denis Fahey described Ireland as "the third most Masonic country in the world" and saw this alleged order as contrary to the creation of an independent Irish State.
== Interactions == Cilostazol is metabolized by CYP3A4 and CYP2C19, two isoenzymes of the cytochrome P450 system. Drugs that inhibit CYP3A4, such as itraconazole, erythromycin, ketoconazole, and diltiazem, are known to interact with cilostazol. The proton pump inhibitor omeprazole, an inhibitor of CYP2C19, increases exposure to the active metabolite of cilostazol. A single report has been made of grapefruit juice possibly increasing the effects of cilostazol; some drug information sources list this as a possible interaction. The FDA-approved labeling of cilostazol notes that grapefruit juice (which is a CYP3A4 inhibitor) increases the drug's maximum concentration by around 50%.
=== Gene cluster === Tolypocladium inflatum, the species currently used for mass production of Cyclosporin, has the biosynthetic genes arranged into a 12-gene cluster. Of these 12 genes, SimA (Q09164) is the cyclosporin synthetase, SimB (CAA02484.1) is the alanine racemase, and SimG (similar to ATQ39432.1) is the polyketide synthase. These genes are associated with an active retrotransposon. Although these sequences are poorly-annotated on GenBank and other databases, 90% similar sequences can be found for the Cyclosporin-producing Beauveria felina (or Amphichorda ~). SimB has two paralogs in the same organism with different but overlapping functions thanks to their low specificity.
Sources: en.wikipedia.org
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.
The first four residues of Selank reproduce the tuftsin sequence Thr-Lys-Pro-Arg. A Pro-Gly-Pro extension at the C-terminus was added to slow enzymatic breakdown and extend residence time.
It holds marketing authorization in Russia, where nasal drop formulations are sold. No equivalent approval exists in the European Union, the United States, or most other countries.
Reports describe modulation of GABA signalling, changes in monoamine turnover and effects on neurotrophic factor expression. These observations come mainly from animal and cell studies. A single unifying mechanism has not been demonstrated.