If you have been reading about tuftsin and want a single page that covers the useful parts, this is it: definitions, context, how it is studied, and the questions that come up repeatedly.
Updated 2026-05-10. 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.
Enzymatic stability motivates the extra three residues at the carboxyl end. Native tuftsin is cleaved quickly by circulating aminopeptidases and carboxypeptidases, which limits its duration of action and its usefulness as a tool compound. Extending the chain with proline-rich segments is a common design tactic because proline constrains the backbone and slows proteolysis. The same Pro-Gly-Pro motif appears in other Russian-developed peptides of the era. Whether the full seven-residue chain is required for activity, or whether it acts mainly as a prodrug releasing tuftsin, remains unresolved.
Selank is a synthetic heptapeptide with the sequence Thr-Lys-Pro-Arg-Pro-Gly-Pro. Its four N-terminal residues reproduce tuftsin, a tetrapeptide fragment of the immunoglobulin heavy chain, while the C-terminal Pro-Gly-Pro extension is a synthetic addition. The peptide has a molecular mass near 752 daltons and carries a net positive charge at physiological pH because of the arginine and lysine side chains. Published indexes list it under the name Selank and the sequence abbreviation TKPRPGP. Solid-phase peptide synthesis is the standard production route for research quantities.
| 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 |
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.
Reversed-phase high-performance liquid chromatography is the standard technique for estimating peptide purity. The result is a peak-area percentage, which describes how much of the detected material elutes as the main peak in one run. Mass spectrometry confirms the molecular mass and can reveal truncated, adducted, or otherwise modified species. Amino acid analysis or tandem mass spectrometry can address sequence fidelity when identity is in doubt. None of these measurements, taken alone, establishes that a sample is fit for any specific purpose.
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.
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.
=== Enzymatic lysis === Enzymatic lysis, also called Lysozyme lysis, involves the use of enzymes to digest the cell wall and release the plasmid DNA. The most commonly used enzyme for this purpose is lysozyme, which breaks down the peptidoglycan in the cell wall of Gram-positive bacteria. Lysozyme is usually added to the bacterial culture, followed by heating and/or shaking the culture to release the plasmid DNA.
== Research use == Separate from its utility as an educational, self-learning, or teaching tool for people with diabetes and their relatives / carers, students and health-care professionals — various research groups around the world have found the freeware AIDA diabetes simulator of use as a way of generating large quantities of realistic blood glucose data for developing and testing out their own diabetes computing prototypes (e.g. for training artificial neural networks, or other decision support research prototypes). Various published examples of this research approach can be found in the scientific literature.
=== EC 1.14.99 Miscellaneous === EC 1.14.99.1: prostaglandin-endoperoxide synthase EC 1.14.99.2: kynurenine 7,8-hydroxylase EC 1.14.99.3: Now EC 1.14.14.18, heme oxygenase (biliverdin-producing) EC 1.14.99.4: progesterone monooxygenase EC 1.14.99.5: Now EC 1.14.19.1, stearoyl-CoA 9-desaturase EC 1.14.99.6: Now EC 1.14.19.2, acyl-[acyl-carrier-protein] desaturase EC 1.14.99.7: Transferred to EC 1.14.13.132, squalene monooxygenase EC 1.14.99.8: Now included with EC 1.14.14.1 unspecific monooxygenase EC 1.14.99.9: Now classified as EC 1.14.14.19, steroid 17α-monooxygenase EC 1.14.99.10: Now EC 1.14.14.16, steroid 21-monooxygenase EC 1.14.99.11: estradiol 6β-monooxygenase EC 1.14.99.12: 4-androstene-3,17-dione monooxygenase EC 1.14.99.13: Now EC 1.14.13.23, 3-hydroxybenzoate 4-monooxygenase EC 1.14.99.14: Now EC 1.14.14.197, progesterone 11α-monooxygenase EC 1.14.99.15: 4-methoxybenzoate monooxygenase (O-demethylating) EC 1.14.99.16: Now EC 1.14.13.72, methylsterol monooxygenase EC 1.14.99.17: Now EC 1.14.16.5, glyceryl-ether monooxygenase EC 1.14.99.18: deleted EC 1.14.99.19: Now classified as EC 1.14.19.77, plasmanylethanolamine desaturase EC 1.14.99.20: phylloquinone monooxygenase (2,3-epoxidizing) EC 1.14.99.21: Latia-luciferin monooxygenase (demethylating) EC 1.14.99.22: ecdysone 20-monooxygenase EC 1.14.99.23: 3-hydroxybenzoate 2-monooxygenase EC 1.14.99.24: steroid 9α-monooxygenase EC 1.14.99.25: Now EC 1.14.19.3, linoleoyl-CoA desaturase EC 1.14.99.26: 2-hydroxypyridine 5-monooxygenase EC 1.14.99.27: Now classified as EC 1.17.3.4, juglone 3-monooxygenase EC 1.14.99.28: Now EC 1.14.14.84, linalool 8-monooxygenase EC 1.14.99.29: deoxyhypusine monooxygenase EC 1.14.99.30: Now EC 1.3.5.6, 9,9′-dicis-ζ-carotene desaturase. EC 1.14.99.31: Now classified as EC 1.14.19.24, myristoyl-CoA 11-(E) desaturase EC 1.14.99.32: Now classified as EC 1.14.19.5, acyl-CoA 11-(Z)-desaturase EC 1.14.99.33: Now EC 1.14.19.39, acyl-lipid Δ12-acetylenase EC 1.14.99.34: monoprenyl isoflavone epoxidase EC 1.14.99.35: thiophene-2-carbonyl-CoA monooxygenase EC 1.14.99.36: Now classified as EC 1.13.11.63, β-carotene 15,15′-dioxygenase EC 1.14.99.37: Now EC 1.14.14.176, taxadiene 5α-hydroxylase EC 1.14.99.38: cholesterol 25-hydroxylase EC 1.14.99.39: ammonia monooxygenase EC 1.14.99.40: Now EC 1.13.11.79, 5,6-dimethylbenzimidazole synthase EC 1.14.99.41: Now EC 1.13.11.75, all-trans-8′-apo-β-carotenal 15,15′-oxygenase EC 1.14.99.42: Now EC 1.13.11.84, crocetin dialdehyde synthase EC 1.14.99.43: Now EC 1.14.14.134, β-amyrin 24-hydroxylase EC 1.14.99.44: diapolycopene oxygenase EC 1.14.99.45: Now EC 1.14.14.158, carotene ε-monooxygenase EC 1.14.99.46: pyrimidine oxygenase EC 1.14.99.47: (+)-larreatricin hydroxylase EC 1.14.99.48: heme oxygenase (staphylobilin-producing) EC 1.14.99.49: Now EC 1.14.15.31, 2-hydroxy-5-methyl-1-naphthoate 7-hydroxylase EC 1.14.99.50: γ-glutamyl hercynylcysteine S-oxide synthase EC 1.14.99.51: hercynylcysteine S-oxide synthase EC 1.14.99.52: L-cysteinyl-L-histidinylsulfoxide synthase EC 1.14.99.53: lytic chitin monooxygenase EC 1.14.99.54: lytic cellulose monooxygenase (C1-hydroxylating) EC 1.14.99.55: lytic starch monooxygenase EC 1.14.99.56: lytic cellulose monooxygenase (C4-dehydrogenating) EC 1.14.99.57: heme oxygenase (mycobilin-producing) EC 1.14.99.58: heme oxygenase (biliverdin-IX-β and δ-forming) EC 1.14.99.59: tryptamine 4-monooxygenase EC 1.14.99.60: 3-demethoxyubiquinol 3-hydroxylase EC 1.14.99.61: cyclooctat-9-en-7-ol 5-monooxygenase EC 1.14.99.62: cyclooctatin synthase EC 1.14.99.63: β-carotene 4-ketolase EC 1.14.99.64: zeaxanthin 4-ketolase EC 1.14.99.65: 4-amino-L-phenylalanyl-[CmlP-peptidyl-carrier-protein] 3-hydroxylase EC 1.14.99.66: [histone H3]-N6,N6-dimethyl-L-lysine4 FAD-dependent demethylase EC 1.14.99.67: α-N-dichloroacetyl-p-aminophenylserinol N-oxygenase EC 1.14.99.68: 4-aminobenzoate N-oxygenase EC 1.14.99.69: tRNA 2-(methylsulfanyl)-N6-isopentenyladenosine37 hydroxylase
=== Regional groups === Head and neck – includes everything above the thoracic inlet Upper limb – includes the hand, wrist, forearm, elbow, arm, shoulder Thorax – the region of the chest from the thoracic inlet to the thoracic diaphragm Human abdomen to the pelvic brim or to the pelvic inlet The back – the spine and its components, the vertebrae, sacrum, coccyx, intervertebral disks Pelvis and perineum – the pelvis consists of everything from the pelvic inlet to the pelvic diaphragm; the perineum is the region between the sex organs and the anus Lower limb – everything below the inguinal ligament, including the hip, the thigh, the knee, the leg, the ankle, the foot
Damage to skeletal muscle may take various forms. Crush and other physical injuries cause damage to muscle cells directly or interfere with blood supply, while non-physical causes interfere with muscle cell metabolism. When damaged, muscle tissue rapidly fills with fluid from the bloodstream, including sodium ions. The swelling itself may lead to destruction of muscle cells, but those cells that survive are subject to various disruptions that lead to rise in intracellular calcium ions; the accumulation of calcium outside the sarcoplasmic reticulum leads to continuous muscle contraction and depletion of ATP, the main carrier of energy in the cell. ATP depletion can itself lead to uncontrolled calcium influx. The persistent contraction of the muscle cell leads to the breakdown of intracellular proteins and the disintegration of the cell. Neutrophil granulocytes—the most abundant type of white blood cell—enter the muscle tissue, producing an inflammatory reaction and releasing reactive oxygen species, particularly after crush injury. Crush syndrome may also cause reperfusion injury when blood flow to decompressed muscle is suddenly restored. The swollen, inflamed muscle may directly compress structures in the same fascial compartment, causing compartment syndrome. The swelling may also further compromise the blood supply to the area. Finally, destroyed muscle cells release potassium ions, phosphate ions, the heme-containing protein myoglobin, the enzyme creatine kinase and uric acid (a breakdown product of purines from DNA) into the blood.
Sources: en.wikipedia.org
=== Prescribing restrictions === Isotretinoin is a teratogen; there is about a 20–35% risk for congenital defects in infants exposed to the drug in utero, and about 30–60% of children exposed to isotretinoin prenatally have been reported to show neurocognitive impairment. Because of this risk, there are strict controls prescribing isotretinoin to women who have potential to become (or be) pregnant while taking isotretinoin and many are strongly advised to terminate their pregnancies because of the 20-60% risk. Isotretinoin is also not recommended for use by breastfeeding women. In the United States, since March 2006, the dispensing of isotretinoin is run through the iPLEDGE program, under the direction of the Food and Drug Administration. Prescribers, pharmacists, and all people to whom the drug is prescribed need to register on the site and log information into it. Women with child-bearing potential must commit to using two forms of effective contraception simultaneously for the duration of isotretinoin therapy and for a month immediately preceding and a month immediately following therapy. Additionally, they must have two negative pregnancy tests 30 days apart and have negative pregnancy tests before each prescription is written. In most countries, isotretinoin can only be prescribed by dermatologists or specialist physicians; some countries also allow limited prescriptions by general practitioners and family doctors. In the United Kingdom and Australia, isotretinoin may be prescribed only by or under the supervision of a consultant dermatologist.
== Routes of administration == Buccal Mucosa (inner cheek): Suitable for buccal administration. Labial Mucosa (inner lips): Suitable for buccal drug administration. Sublingual Mucosa (under tongue): Ideal for sublingual administration due to high permeability. Sublabial Mucosa (under lower lip): Suitable for sublabial administration due to good vascularization.
where [A] is the concentration of A, etc., is independent of the analytical concentration of the reactants. For this reason, equilibrium constants for solutions are usually determined in media of high ionic strength. Kc varies with ionic strength, temperature and pressure (or volume). Likewise Kp for gases depends on partial pressure. These constants are easier to measure and encountered in high-school chemistry courses.
Elements of the VC 5th Division attacked Xuân Lộc Base Camp which was defended by the 7th Battalion, 9th Artillery Regiment and the 2nd Battalion, 35th Artillery Regiment, 54th Artillery Group. The VC penetrated the perimeter but were eventually driven out airstrikes and a unit of the 11th Armored Cavalry Regiment. The attack resulted in 24 VC and 14 U.S. killed.
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.
Selank is a seven-amino-acid peptide built from the tuftsin sequence plus a Pro-Gly-Pro tail. It is produced by chemical synthesis rather than extracted from a natural source. The free peptide is usually supplied as a lyophilised powder or in an aqueous formulation.