This is a working overview of lyophilization, written for readers who want more than a one-paragraph summary but less than a textbook.
This page was last updated on 2025-11-25 and is reviewed periodically as new material appears.
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.
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.
Selank is a synthetic heptapeptide with the sequence Thr-Lys-Pro-Arg-Pro-Gly-Pro, written TKPRPGP in one-letter notation. Its structure consists of the immunomodulatory tetrapeptide tuftsin, Thr-Lys-Pro-Arg, extended at the carboxyl terminus by a Pro-Gly-Pro segment. The molecular formula is commonly given as C33H57N11O9, corresponding to a monoisotopic mass near 751.4 Da and an average molecular mass near 751.9 Da. All seven residues are proteinogenic amino acids, and the molecule carries no modified side chains or non-natural linkages.
| 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 |
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.
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.
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.
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.
=== Nuclear === In addition to its reported mitochondrial function, some researchers have proposed a very small pool of active nuclear SIRT3 exists. This pool is reported to consist of the long form of SIRT3 and has been suggested to have histone deacetylase activity. The observation that SIRT3 has nuclear activity came from a report that SIRT3 protected cardiomyocytes from stress mediated cell death and that this effect was due to deacetylation of a nuclear factor, Ku-70.
== Continuous production == A common method of increasing efficiency in industrial chromatography is continuous production. There, this is done with SMB (Simulated Moving Bed). In liquid-liquid chromatography, there is no need to simulate a moving bed, as we can move it in reality, and therefore it is TMB, i.e. True Moving Bed. The essence of TMB is to continuously switch the device between ASC and DSC modes, effectively creating a moving bed. This technique is much cheaper than SMB, and its efficiency is not lagging behind. TMB systems are available from mg to tone capacity from LiLiChro.
==== Legal Considerations ==== In the United States brands applied by any method often must be registered with a state or county office. In some jurisdictions, it is illegal to brand an animal without first registering the design with a state office. The following table summarizes the legal recognition and requirements for equine freeze brands in the United States:
The French Laundry event took place on November 6, and between November 5 and December 7 over 442,000 new signatures were submitted and verified; 1,664,010 verified signatures, representing roughly 98% of the final total of 1,719,900, were submitted between November 2020 and March 17, 2021. In response to the criticism, Newsom said in a statement, "While the First Partner and I followed the restaurant's health protocols and took safety precautions, I should have modeled better behavior and not joined the dinner." During the campaign, Newsom compared the recall effort to the attempts to overturn the 2020 United States presidential election. On September 14, 2021, the recall election was held, and only 38% voted to recall Newsom, so he remained in office.
Sources: en.wikipedia.org
l is the thickness of that material through which the light travels, and a(z) is the decadic attenuation coefficient of that material at z. If a(z) is uniform along the path, the attenuation is said to be a linear attenuation, and the relation becomes
== Potential therapies == A potential novel treatment, the NMT inhibitor, has been shown to completely inhibit Lassa (LAS) and Junín (JUN) viral infections in cells based assays. Another host-directed antiviral acts on EPRS1 which in turn acts, in human cells, as a proviral factor in mammarenaviruses infection, including LCMV, JUNV, and LASV, and its inhibition using halofuginon compound, a prolyl domain inhibitor of EPRS1, completely abolishes the viral infection by interrupting viral assembly and budding. PKR has been shown to act as a proviral factor while the inhibition of its kinase activity restricted the virus replication and infectivity.
== Early life, education, and career == Wittman was born in Washington, D.C., the son of adoptive parents Regina C. (née Wood) and Frank Joseph Wittman. His father was of German descent and his mother's ancestors included immigrants from Ireland and Canada. He grew up in Henrico County, Virginia. He attended the Virginia Polytechnic Institute and State University (Virginia Tech) as a member of the Corps of Cadets and Army ROTC and studied biology. While at Virginia Tech, he spent the summers working at a tomato cannery and on a fishing vessel. Also while in college, Wittman was a member of the Delta Tau Delta fraternity. He earned a master's degree in public health from the University of North Carolina at Chapel Hill in 1990 and a Ph.D. from Virginia Commonwealth University in 2002. Wittman worked for 20 years with the Virginia Department of Health. He served as an environmental health specialist and was field director for the Division of Shellfish Sanitation. Wittman served on the Montross Town Council from 1986 to 1996 and as mayor of the Town of Montross from 1992 to 1996. Two of his major initiatives in this office were the overhaul of the sewage system and the development of a computerized system for tax billing. From 1996 to 2005, Wittman served on the Westmoreland County Board of Supervisors, the last two years as chair. He helped create new libraries and pushed for raises in teacher salaries.
In chemistry, an ionophore (from Greek ion and -phore 'ion carrier') is a chemical species that reversibly binds ions. Many ionophores are lipid-soluble entities that transport ions across the cell membrane. Ionophores catalyze ion transport across hydrophobic membranes, such as liquid polymeric membranes (carrier-based ion selective electrodes) or lipid bilayers found in the living cells or synthetic vesicles (liposomes). Structurally, an ionophore contains a hydrophilic center and a hydrophobic portion that interacts with the membrane. Some ionophores are synthesized by microorganisms to import ions into their cells. Synthetic ion carriers have also been prepared. Ionophores selective for cations and anions have found many applications in analysis. These compounds have also shown to have various biological effects and a synergistic effect when combined with the ion they bind.
The Raleigh tornado produced over $77 million in damage, along with four fatalities (two in the city of Raleigh, and two in Nash County) and 154 injuries. The damage path from the storm was measured at 84 mi (135 km) long, and .5 mi (0.8 km) wide at times. The tornado was rated F4. In 1991, two large skyscrapers in Raleigh were completed, First Union Capitol Center and Two Hannover Square, along with the popular Coastal Credit Union Music Park at Walnut Creek in southeast Raleigh. In 1996, the Olympic Flame passed through Raleigh while on its way to the 1996 Summer Olympics in Atlanta. Also in 1996, Hurricane Fran struck the area, causing massive flooding and extensive structural damage. In addition, WRAL-TV became the first High-Definition broadcast station in the world. In 1997, the Hartford Whalers of the National Hockey League announced their intention to move to Raleigh as the Carolina Hurricanes, becoming the city's first major league professional sports franchise. In 1999, the Raleigh Entertainment and Sports Arena (later renamed the RBC Center and now called Lenovo Center), opened to provide a home for the Hurricanes and the NC State Wolfpack men's basketball team, as well as an up-to-date major concert venue.
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.
The sequence is Thr-Lys-Pro-Arg-Pro-Gly-Pro, written TKPRPGP in one-letter code. It combines the tetrapeptide tuftsin with a carboxyl-terminal Pro-Gly-Pro extension. This full sequence identifies the molecule more precisely than the research name.