The short version of lyophilization fits in a sentence. The long version — which is the one that helps — is below.
This page was last updated on 2026-05-20 and is reviewed periodically as new material appears.
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.
Selank is a synthetic heptapeptide with the sequence Thr-Lys-Pro-Arg-Pro-Gly-Pro. It was designed at the Institute of Molecular Genetics of the Russian Academy of Sciences as a structural analogue of tuftsin, a naturally occurring tetrapeptide fragment of the immunoglobulin heavy chain. The added Pro-Gly-Pro tail was intended to slow enzymatic degradation and extend biological activity. In Russia it is registered as an anxiolytic nasal preparation, while regulators elsewhere have not approved it for clinical use.
Proposed mechanisms centre on modulation of the GABAergic system, with reports of altered expression of genes related to GABA-A receptor subunits and changed monoamine turnover. Some studies describe inhibition of enkephalinase, the enzyme that degrades endogenous enkephalins, which may prolong opioid peptide signalling. Effects on brain-derived neurotrophic factor and on cytokine expression have also been reported. These findings come largely from animal models and small human studies, and the precise primary target remains unresolved.
Published clinical evidence is limited. Most controlled trials were conducted in Russia, enrolled modest numbers of participants, and appeared in Russian-language journals, which restricts independent verification. Reported outcomes include lower anxiety scores, improved attention and memory measures, and changes in fatigue ratings. Reviews written in English note methodological limitations such as small samples and inconsistent endpoints. Whether the compound produces clinically meaningful benefit relative to established anxiolytics is therefore an open question rather than an established finding.
| Property | Value | Notes |
|---|---|---|
| Typical purity specification | 95 percent or higher by RP-HPLC | Area percentage of the main peak |
| Identity confirmation | Electrospray ionization mass spectrometry | Observed mass compared with the theoretical value near 751.9 Da |
| Recommended dry storage | -20 °C, desiccated | -80 °C for multi-year archival material |
| Solution handling | Prepare fresh; avoid long storage | Sterile filtration reduces microbial load |
| Common synonyms | TKPRPGP; TP-7 | Sequence code and laboratory designation used interchangeably |
Selank is a synthetic heptapeptide with the sequence Thr-Lys-Pro-Arg-Pro-Gly-Pro, frequently abbreviated as TKPRPGP. It was designed as a structural analogue of tuftsin, a naturally occurring tetrapeptide released by enzymatic cleavage of the immunoglobulin heavy chain. The two additional proline residues at the C-terminal end extend the parent chain and change how the molecule behaves in solution. The free peptide has a calculated molecular mass of approximately 751.9 g/mol and is generally supplied as a lyophilised white to off-white powder.
Development work on the compound began in the 1980s and 1990s at the Institute of Molecular Genetics in Moscow, within the same research programme that produced the peptide Semax. Early investigators sought a tuftsin derivative with improved resistance to enzymatic breakdown and with activity in the central nervous system after peripheral administration. Most of the primary literature from this period was published in Russian, a factor that still shapes how easily the findings can be checked by outside groups.
Naming for this compound is not fully standardised in English sources. The spelling Selanc appears in some transliterations, and catalogue entries may instead list the peptide sequence itself as the identifier. Reference material sometimes groups it with other short synthetic peptides studied for behavioural effects, which can create confusion when citations are compared. Distinguishing the exact sequence from related tuftsin analogues is therefore a practical first step when reviewing any dataset or specification sheet.
Laboratory work relies on standard behavioral paradigms. Rodents are tested in the elevated plus maze, open field, and passive avoidance tasks, with outcomes compared against diazepam or vehicle controls. Intranasal dosing is used most often because it bypasses first-pass metabolism, though intraperitoneal and intravenous routes also appear in published protocols. Biochemical endpoints include tissue BDNF concentrations, cytokine levels, and monoamine metabolites. Human data are limited to small Russian trials reporting reduced anxiety scores; most were not prospectively registered, and few employed independent outcome assessment.
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.
The deal was to constitute a reverse merger, whereby Allergan acquired Pfizer, with the new company then changing its name to "Pfizer, plc". On April 6, 2016, Pfizer and Allergan terminated the merger agreement after the Obama administration and the United States Department of the Treasury introduced new laws intended to limit corporate inversions (the extent to which companies could move their headquarters overseas in order to reduce the amount of taxes they pay). In June 2016, the company acquired Anacor Pharmaceuticals for $5.2 billion, expanding its portfolio in both inflammation and immunology drugs areas. In August 2016, the company made a $40 million bid for the assets of BIND Therapeutics, which was in bankruptcy. The same month, the company acquired Bamboo Therapeutics for $645 million, expanding its gene therapy offerings. In September 2016, the company acquired cancer drug-maker Medivation for $14 billion. In October 2016, the company licensed the anti-CTLA4 monoclonal antibody, ONC-392, from OncoImmune. In November 2016, Pfizer funded a $3,435,600 study with the CDC Foundation to research "screen-and-treat" strategies for cryptococcal disease in Botswana. In December 2016, Pfizer acquired AstraZeneca's small-molecule antibiotics business for $1.575 billion. In January 2018, Pfizer announced that it would end its work on research into treatments for Alzheimer's disease and Parkinsonism (a symptom of Parkinson's disease and other conditions). The company said about 300 researchers would lose their jobs.
Religious leaders often turned to versions of exorcism to treat mental disorders often utilizing methods that many consider to be cruel or barbaric methods. Trepanning was one of these methods used throughout history. In the 6th century AD, Lin Xie carried out an early psychological experiment, in which he asked people to draw a square with one hand and at the same time draw a circle with the other (ostensibly to test people's vulnerability to distraction). It has been cited that this was an early psychiatric experiment. The Islamic Golden Age fostered early studies in Islamic psychology and psychiatry, with many scholars writing about mental disorders. The Persian physician Muhammad ibn Zakariya al-Razi, also known as "Rhazes", wrote texts about psychiatric conditions in the 9th century. As chief physician of a hospital in Baghdad, he was also the director of one of the first bimaristans in the world. The first bimaristan was founded in Baghdad in the 9th century, and several others of increasing complexity were created throughout the Arab world in the following centuries. Some of the bimaristans contained wards dedicated to the care of mentally ill patients. During the Middle Ages, Psychiatric hospitals and lunatic asylums were built and expanded throughout Europe. Specialist hospitals such as Bethlem Royal Hospital in London were built in medieval Europe from the 13th century to treat mental disorders, but were used only as custodial institutions and did not provide any type of treatment. It is the oldest extant psychiatric hospital in the world.
Though once thought of as scavengers, Neanderthals are now considered apex predators. They appear to have eaten predominantly what was abundant within their immediate surroundings, consequently consuming across their range a wide array of meats and plants, the relative proportion of which varied substantially geographically. Cro-Magnons, in contrast, seem to have maintained a more diverse diet even in settings where certain foods would have been harder to procure; for example, Neanderthals living in forests ate about the same proportion of foodplants as Cro-Magnons, but Neanderthals on open steppe (where foodplants are harder to find) ate far less foodplants. In many European sites, prey items include red deer, reindeer, horse, aurochs, ibex, and steppe bison. Neanderthals in Southwest Asia more commonly hunted mountain gazelle, Persian fallow deer, wild goat, and camels. They may have less frequently taken down larger Pleistocene megafauna whenever locally abundant, such as woolly mammoth and woolly rhinoceros. At the 125,000 year old Neumark-Nord site, Germany, there is evidence of regular hunting of straight-tusked elephants maybe every 5 to 6 years. Some waterside communities ate fish and shellfish—and at Vanguard Cave, Gibraltar, dolphin and Mediterranean monk seal. Neanderthals also hunted small game, and some caves show evidence of regular rabbit and tortoise consumption. At Gibraltar sites, there are butchered remains of 143 different bird species, many ground-dwelling such as the common quail, corn crake, woodlark, and crested lark.
Sources: en.wikipedia.org
This broad classification is based on the empirical makeup and atomic structure of the solid materials, and most solids fall into one of these broad categories. An item that is often made from each of these materials types is the beverage container. The material types used for beverage containers accordingly provide different advantages and disadvantages, depending on the material used. Ceramic (glass) containers are optically transparent, impervious to the passage of carbon dioxide, relatively inexpensive, and are easily recycled, but are also heavy and fracture easily. Metal (aluminum alloy) is relatively strong, is a good barrier to the diffusion of carbon dioxide, and is easily recycled. However, the cans are opaque, expensive to produce, and are easily dented and punctured. Polymers (polyethylene plastic) are relatively strong, can be optically transparent, are inexpensive and lightweight, and can be recyclable, but are not as impervious to the passage of carbon dioxide as aluminum and glass.
=== Myopathies === Inflammatory myopathies are caused by the immune system inappropriately attacking components of muscle, leading to signs of muscle inflammation. They may occur in conjunction with other immune disorders, such as systemic sclerosis, and include dermatomyositis, polymyositis, and inclusion body myositis.
It also introduced new menu items including a turkey burger, tater tots and a "triple double", although the latter prompted a copyright infringement lawsuit from In-n-Out Burger, as well as a class-action lawsuit for false advertising. The restaurant faced difficulties in continuing to grow, in part as shoppers began to shift away from shopping in traditional retail centers where its restaurants were concentrated. At the same time, larger restaurant chains increased their efforts to grow sales and brought on higher-quality menu items to compete with Smashburger and restaurants like it. Subsequently, Smashburger saw its overall same-store sales decline as a number of other local "better burger" concepts grew. Crane left as CEO in April 2016, and was replaced by Mike Nolan, but he resigned nine months later and Ryan took over the role. The restaurant thus condensed its expansion strategy to focus on existing markets and began mentorship programs to develop leadership talent from within its ranks of workers. It also bought back some franchise restaurants in several major markets. Smashburger competitors like Shake Shack and Five Guys experienced many of these difficulties, as well. In 2016, Smashburger was estimated to have $338.3 million in sales. On 13 February 2018, Jollibee increased its ownership stake to 85 percent of Smashburger in another $100 million deal. In making the acquisition, the companies said the move would allow Smashburger to further expand its presence in southeast Asia.
Sources: en.wikipedia.org
Sealed, desiccated storage at -20 °C or colder is the standard recommendation for research-grade material. Vials should reach room temperature before they are opened, which limits condensation. Repeated temperature cycling is discouraged.
A reported purity value reflects the share of the main peak in one chromatographic run and says nothing about identity. Confirming that the expected sequence is present requires a separate measurement such as mass spectrometry. Purity and identity are distinct questions.
A mass spectrum reports the molecular masses present in a sample and shows whether they match the value expected for selank, near 751.9 Da. It also flags common artifacts such as truncation or adduct formation. It does not establish correct stereochemistry or complete sequence order on its own.
It is a seven-amino-acid peptide, Thr-Lys-Pro-Arg-Pro-Gly-Pro, produced by chemical synthesis rather than extracted from biological tissue. Its design is based on tuftsin, a natural immunomodulatory tetrapeptide. The C-terminal Pro-Gly-Pro segment is a common stabilising motif in short regulatory peptides.