A practical reference on peptide stability: what it is, how it behaves, what the literature reports, and where the honest uncertainties sit.
This page was last updated on 2026-06-09 and is reviewed periodically as new material appears.
Animal studies have examined behaviour in tests of anxiety, memory retention and stress response, and several report changes in neurotrophic or neurotransmitter-related markers. The human evidence base is much smaller, consisting mainly of short trials conducted in Russia with limited reporting in English-language journals. Sample sizes are modest and outcome measures vary between studies, so the findings are best described as preliminary. Independent replication under modern trial standards has not been widely reported.
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.
Handling follows standard practice for research peptides. Material is weighed in a low-humidity environment because the powder absorbs atmospheric moisture. Purity is reported as the percentage area of the main peak in a chromatogram, with specifications commonly set at 95 percent or higher; values below that threshold indicate the presence of truncated or modified species. Residual trifluoroacetate from purification is often present and may affect mass balance. Certificates of analysis should state the analytical method, the column and gradient used, and the lot-specific retention time so that results can be compared across suppliers.
Identity and purity of selank are established with reversed-phase high-performance liquid chromatography coupled to mass spectrometry. The peptide elutes from C18 columns with acetonitrile gradients in water containing trifluoroacetic acid or formic acid, and detection is usually performed by ultraviolet absorbance near 214 nm. Electrospray ionization in positive mode gives a doubly protonated ion near m/z 377, consistent with a mass of about 752 Da. Amino acid analysis or tandem mass spectrometry of fragment ions confirms the sequence. Because the molecule has no aromatic residues, it lacks a usable 280 nm chromophore, so low-wavelength detection or mass spectrometry is required.
Peptide bonds in selank are susceptible to hydrolysis under strongly acidic or basic conditions, and the terminal proline residues are vulnerable to exopeptidase activity in biological samples. Lyophilized powder stored dry at -20 °C typically remains stable for extended periods, whereas aqueous solutions degrade faster and may lose measurable purity within days to weeks depending on pH, temperature, and microbial load. Repeated freeze-thaw cycles promote aggregation and adsorption to container surfaces. For analytical work, solutions are usually prepared fresh, kept cold, and used within a single working day.
| Property | Value | Notes |
|---|---|---|
| Common route | Intranasal | Also injected in some animal work |
| Solubility class | Freely soluble in water | Solid form is hygroscopic |
| Typical storage | About -20 degrees Celsius | Keep desiccated and dark |
| Purity method | Reverse-phase HPLC | Reported as area percent |
| Confirmatory method | Mass spectrometry | Verifies expected molecular mass |
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.
Measuring peptide exposure inside the brain is technically difficult. Selank is degraded rapidly in plasma, and assays must separate intact peptide from fragments, which favors targeted mass spectrometry over immunoassays alone. Reported half-lives are short, on the order of minutes, so effects observed hours later are attributed to downstream signaling rather than to the parent compound. Blood-brain barrier permeability is debated and rarely quantified directly. Gaps include absent dose-response characterization, inconsistent reporting of purity, and almost no pharmacokinetic data from human participants.
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.
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.
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.
Malignant hyperthermia (MH) is a type of severe reaction that occurs in response to particular medications used during general anesthesia, among those who are susceptible. Symptoms include muscle rigidity, fever, and a fast heart rate. Complications can include muscle breakdown and high blood potassium. Most people who are susceptible to MH are generally unaffected when not exposed to triggering agents. Exposure to triggering agents (certain volatile anesthetic agents or succinylcholine) can lead to the development of MH in those who are susceptible. Susceptibility can occur due to at least six genetic mutations, with the most common one being of the RYR1 gene. These genetic variations are often inherited in an autosomal dominant manner. The condition may also occur as a new mutation or be associated with a number of inherited muscle diseases, such as central core disease. In susceptible individuals, the medications induce the release of stored calcium ions within muscle cells. The resulting increase in calcium concentrations within the cells cause the muscle fibers to contract. This generates excessive heat and results in metabolic acidosis. Diagnosis is based on symptoms in the appropriate situation. Family members may be tested to see if they are susceptible by muscle biopsy or genetic testing. Treatment is with dantrolene and rapid cooling along with other supportive measures. The avoidance of potential triggers is recommended in susceptible people. The condition affects one in 5,000 to 50,000 cases where people are given anesthetic gases.
SOLAR (acronym for Sound of Los Angeles Records) was an American record label founded in 1978 by Dick Griffey, reconstituted out of Soul Train Records only three years after it was founded with Soul Train television show host and creator Don Cornelius.
=== Meiosis === When C. brunneus was exposed to X-irradiation during the zygotene-early pachytene stages of meiosis, this treatment caused a significant increase in meiotic cell chiasma frequency. Chiasma frequency was scored during the subsequent diplotene-diakinesis stages of meiosis.
The United Nations Convention Against Illicit Traffic in Narcotic Drugs and Psychotropic Substances was adopted in 1988, entered into force on November 11, 1990, has been joined by 191 countries. The convention addressed concern over the rapid growth in international drug trafficking. According to the UNODC, it "provides comprehensive measures against drug trafficking, including provisions against money laundering and the diversion of precursor chemicals". The treaty essentially "criminalized the entire drug market chain, from cultivation/production to shipment, sale, and possession".
=== Apodization in signal processing === The term apodization is used frequently in publications on Fourier-transform infrared (FTIR) signal processing. An example of apodization is the use of the Hann window in fast Fourier transform analyzers to smooth the discontinuities at the beginning and end of the sampled time record.
Sources: en.wikipedia.org
== Medical uses == Penbutolol is used to treat mild to moderate high blood pressure. Like other beta blockers it is not a first line treatment for this indication. It should not be used or only used with caution in people with heart failure and people with asthma. It may mask signs of low blood sugar in people with diabetes and it may mask signs of hyperthyroidism. Animal studies showed some signs of potential trouble for women who are pregnant, and it has not been tested in women who are pregnant. It is not known if penbutolol is secreted in breast milk.
== Ecology == Maqui berries are a favored food for birds at the end of summer. Deforestation of the Valdivian temperate forests in Chile suppresses seed dispersal by birds and leads to inbreeding depression. It is viewed as an invasive species in the Juan Fernandez Islands.
=== Territorial disputes, internal conflicts, and armed conflicts === A 2017 study found that autocratic leaders whose states were involved in international rivalries over disputed territory were more likely to be overthrown in a coup. The authors of the study provide the following logic for why this is:Autocratic incumbents invested in spatial rivalries need to strengthen the military in order to compete with a foreign adversary. The imperative of developing a strong army puts dictators in a paradoxical situation: to compete with a rival state, they must empower the very agency—the military—that is most likely to threaten their own survival in office.However, two 2016 studies found that leaders who were involved in militarized confrontations and conflicts were less likely to face a coup. A 2019 study found that states that had recently signed civil war peace agreements were much more likely to experience coups, in particular when those agreements contained provisions that jeopardized the interests of the military.
=== Phase 2 === 18F PI-2620 ([18F]PI-2620; PI-2620) – positron-emission tomography (PET) enhancer – diagnosis [16] AB-1005 (AAV2-GDNF; AMT-140; adeno-associated-virus-GDNF therapy) – gene transference and glial cell line-derived neurotrophic factor (GDNF) expression stimulant [17] Affitope PD01 (ACI-7104; ACI-7104.056; Affitope-PD01A; PD-01; PD-01A) – peptide vaccine against α-synuclein [18] Altropane 123I (dopamine transporter (DAT) imaging radiopharmaceutical) – dopamine reuptake inhibitor (DRI) and single-photon emission-computed tomography (SPECT) enhancer – diagnosis [19] Apomorphine inhalation (AZ-009; Staccato® Apomorphine) – non-selective dopamine receptor agonist and other actions [20] Apomorphine intranasal (AL-101) – non-selective dopamine receptor agonist and other actions [21] Aprepitant/pramipexole (ALTO-208; CTC-413) – combination of aprepitant (neurokinin NK1 receptor antagonist) and pramipexole (dopamine D2-like receptor agonist) [22] Bezisterim (17α-ethynyl-5-androstene-3β,7β,17β-triol; HE-3286; NE-3107; Triolex) – undefined mechanism of action (synthetic androstenetriol analogue and anti-inflammatory) [23] Blarcamesine (AE-37; ANA001; ANAVEX 2-73) – sigma σ1 receptor agonist, muscarinic acetylcholine M1 receptor agonist, and ionotropic glutamate NMDA receptor agonist [24] Buspirone/zolmitriptan (AV-2860; JM-010) – combination of buspirone (serotonin 5-HT1A receptor agonist and other actions) and zolmitriptan (serotonin 5-HT1B and 5-HT1D receptor agonist) – drug-induced dyskinesia in Parkinson's disease [25] Carbidopa/levodopa (DopaFuse; levodopa/carbidopa continuous release) – combination of carbidopa (aromatic L-amino acid decarboxylase (AAAD) inhibitor) and levodopa (dopamine precursor) [26] Carbidopa/levodopa intranasal (INP-107; POD™ carbidopa/levodopa) – combination of carbidopa (aromatic L-amino acid decarboxylase (AAAD) inhibitor) and levodopa (dopamine precursor) [27] DA-9805 – antioxidant and mitochondrial protein modulator [28] Deferiprone (CGP-37391; CMX-001; CP-020; CP-20; CRMD-001; Ferriprox; Kelfer; L1; Upkanz) – chelating agent [29] EPI-589 ((R)-troloxamide quinone; kinoquinone) – NAD(P)H dehydrogenase (quinone) modulator and antioxidant [30] FNP-150 – undefined mechanism of action [31] Gemfibrozil (FHL-301) – peroxisome proliferator-activated receptor alpha (PPARα) agonist [32] Glovadalen (UCB-0022) – dopamine D1 receptor positive allosteric modulator [33] GRF-6021 (AKST-6021) – plasma protein fraction and neurogenesis stimulant [34] ION-859 (BIIB-094; ION859; IONIS-BIIB7Rx) – leucine-rich repeat kinase 2 (LRRK2) inhibitor [35] Lazucirnon (AKST-4290; ALK-429; ALK-4290) – chemokine CCL11 inhibitor [36] Levetiracetam low-dose (AGB-101) – synaptic vesicle glycoprotein 2A (SV2A) modulator [37] Levodopa (TR-012001) – dopamine precursor and indirect non-selective dopamine receptor agonist [38] Levodopa intranasal (INP103; POD™ levodopa) – dopamine precursor and indirect non-selective dopamine receptor agonist [39] Matsupexole (AM006; KDT-3594) – dopamine receptor agonist [40] Minzasolmin (DLX-313; UCB-0599) – α-synuclein misfolding inhibitor [41] Nilotinib (KFRX-01) – Bcr-Abl tyrosine kinase inhibitor and discoidin domain receptor antagonist [42] Pariceract (BIA 28-6156; LTI-291) – β-glucocerebrosidase (GCase) activator [43] Pegsebrenatide (NLY-01; Olaedin; pegylated exenatide; TLY-001) – glucagon-like peptide-1 receptor (GLP1R) agonist [44] Pirepemat (IRL-752) – various actions [45] Pramipexole – dopamine D2, D3, and D4 receptor agonist [46] Prasinezumab (NEOD-002; PRX-002; RG-7935; RO-7046015) – monoclonal antibody against α-synuclein [47] Pridopidine (ACR-16; ASP-2314; FR-310826; Huntexil; Nurzigma; TV-7820) – sigma σ1 receptor agonist and other actions [48] Radotinib (IY-5511; Supect) – Bcr-Abl tyrosine kinase inhibitor and other actions [49] Risvodetinib (Ikt-148009; IkT148009; risvo) – Bcr-Abl tyrosine kinase inhibitor [50] Squalamine (ENT-01; Enterin-01; kenterin) – various actions [51] Tributyrin (glyceryl tributyrate) – butyric acid (butyrate) prodrug and various actions [52] [53] Usnoflast (ZYIL-1) – NLR family pyrin domain containing 3 (NLRP3) inhibitor [54] Vatiquinone (α-tocotrienol quinone; vincerenone; EPI-743 and PTC-743) – coenzyme Q10 analogue, antioxidant, oxidoreductase inhibitor, 15-lipoxygenase (15-LOX/ALOX15) inhibitor [55] Vodobatinib (K-0706; SCO-088; SUN-K706; SUN-K0706) – Bcr-Abl tyrosine kinase inhibitor [56] VTX-3232 – NLR family pyrin domain containing 3 (NLRP3) inhibitor [57] Vutiglabridin (HSG-4112) – paraoxonase 2 (PON2) agonist and glabridin analogue [58] WID-2101 – undefined mechanism of action [59] XJN-010 – undefined mechanism of action [60]
Sources: en.wikipedia.org
Most published work uses intranasal application, either as drops or as a nasal spray. Injection routes appear in a smaller set of animal experiments. Oral use is uncommon in the literature because peptide breakdown and poor absorption limit this route.
Reported human trials are few, brief and originate mainly from one country. They describe effects on anxiety-related measures, but sample sizes are small and reporting is limited. The results are widely regarded as preliminary rather than confirmed.
Reverse-phase liquid chromatography is used to assess purity and separation of related impurities. Mass spectrometry confirms that the observed molecular mass matches the expected peptide. A certificate of analysis from the supplier is the usual document of record.
Identity is confirmed by matching the retention time in reversed-phase chromatography against a reference standard and by measuring the molecular mass with mass spectrometry. Tandem mass spectrometry or amino acid analysis can verify the sequence of the seven residues. Because the peptide contains no aromatic amino acids, detection at 280 nm is not useful.