A practical reference on lyophilization: what it is, how it behaves, what the literature reports, and where the honest uncertainties sit.
This page was last updated on 2026-03-11 and is reviewed periodically as new material appears.
Lyophilized selank is normally supplied as a dry powder and is considered stable for extended periods when kept cold and dry. Moisture uptake is the main practical threat, because absorbed water promotes both hydrolysis and aggregation in the solid state. Vials are usually warmed to room temperature before opening so that condensation does not form on the powder. Supplier documentation commonly specifies -20 °C for routine storage, with -80 °C used for material intended to be archived for years.
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.
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.
Development took place at the Institute of Molecular Genetics of the Russian Academy of Sciences, where a series of short peptides were designed in the 1980s and 1990s. Selank was selected from variants of tuftsin that showed resistance to plasma peptidases. Russian regulatory approval covers it as an anxiolytic agent given intranasally. Outside that market the compound is normally handled as a research chemical rather than a medicine, and no widely recognised international pharmacopoeial monograph exists. The name Selank is a coined trade designation rather than a systematic chemical name.
| 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 |
Quantification in biological matrices relies on liquid chromatography coupled to tandem mass spectrometry with stable-isotope internal standards. Low plasma concentrations and adsorption to container surfaces both complicate measurement. Solid-phase extraction is often needed to reduce matrix interference before injection. Reported limits of quantification differ widely between laboratories, which makes direct comparison of pharmacokinetic results difficult and limits meta-analysis.
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.
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.
More importantly to the officers of the Supreme Council, the Grand Lodges of Europe were fractured politically, choosing to side with either the Grand Lodge of England or the Grand Orient of France over the direction of the movement itself. In 1868, Jose Orberá y Carrión, the Provisional Governor of the Archbishopric of Cuba, published a circular condemning Freemasonry in Cuba, claiming that it was a secret religion that went against the doctrine of Catholicism. He also asked all those sinners to return to the church. Maximiliano Galan replied that Freemasons in the Spanish territories were acting according to the teachings of Christ, and that the Catholic Church was now persecuting Freemasons in the same way that Ancient Rome had treated early Christians. Freemasons fought on both sides of the war. Donato Mármol, a General of the Cuban Liberation Army, was also a high-ranking Freemason. On one occasion, when his troops captured a Spanish convoy on the battlefield, one of the Spanish lieutenants asked to see Mármol. The lieutenant was also a Freemason, and after they greeted each other using Masonic gestures, the lieutenant convinced General Mármol that the convoy was delivering humanitarian aid, not military supplies. General Mármol then let the convoy on their way, to the displeasure of his subordinate officers. By the beginning of the year 1869, most of the members of Colon Freemasonry were under surveillance by the Spanish.
== See also == Defibrotide - a similar mixture of DNA fragments purified from pig intestinal mucosa and used as an anticoagulant. Silk peptides - a mixture of hydrolysed silk proteins used for similar cosmetic applications.
Physical effects include increased heart rate, difficulty breathing, nausea, and behavioral problems in children whose mothers used cannabis during pregnancy; short-term side effects may also include dry mouth and red eyes. Long-term adverse effects may include addiction, decreased mental ability in those who started regular use as adolescents, heart disease, chronic coughing, susceptibility to respiratory infections, and cannabinoid hyperemesis syndrome. Cannabis is mostly used recreationally or as a medicinal drug, although it may also be used for spiritual purposes. Evidence supports only a few approved uses of cannabinoids and most medical claims, such as efficacy for insomnia or acute pain, lack sufficient evidence. In 2013, between 128 and 232 million people used cannabis (2.7% to 4.9% of the global population between the ages of 15 and 65). It is the most commonly used largely-illegal drug in the world, with the highest use among adults in Zambia, the United States, Canada, and Nigeria. Since the 1970s, the potency of illicit cannabis has increased, with THC levels rising and CBD levels dropping. Cannabis plants have been grown since at least the 3rd millennium BCE and there is evidence of it being smoked for its psychoactive effects around 500 BCE in the Pamir Mountains, Central Asia. Since the 14th century, cannabis has been subject to legal restrictions. The possession, use, and cultivation of cannabis has been illegal in most countries since the 20th century. Uruguay became the first country to legalize recreational use of cannabis in 2013.
Sources: en.wikipedia.org
==== Drugs with unknown mechanisms of action ==== Amantadine (Symmetrel) – unknown mechanism of action and ionotropic glutamate NMDA receptor antagonist (indirect dopaminergic agent) Amantadine extended release (ADS-5101; ADS-5102; Gocovri; Nurelin) – unknown mechanism of action and ionotropic glutamate NMDA receptor antagonist (indirect dopaminergic agent) – drug-induced dyskinesia in Parkinson's disease [343] Budipine (BY-701; Parkinsan) – unknown mechanism of action and ionotropic glutamate NMDA receptor antagonist [344]
== Analysis and characterization == Numerous destructive and non-destructive evaluation (NDE) methods exist for characterizing coatings. The most common destructive method is microscopy of a mounted cross-section of the coating and its substrate. The most common non-destructive techniques include ultrasonic thickness measurement, X-ray fluorescence (XRF), X-Ray diffraction (XRD), photothermal coating thickness measurement and micro hardness indentation. X-ray photoelectron spectroscopy (XPS) is also a classical characterization method to investigate the chemical composition of the nanometer thick surface layer of a material. Scanning electron microscopy coupled with energy dispersive X-ray spectrometry (SEM-EDX, or SEM-EDS) allows to visualize the surface texture and to probe its elementary chemical composition. Other characterization methods include transmission electron microscopy (TEM), atomic force microscopy (AFM), scanning tunneling microscope (STM), and Rutherford backscattering spectrometry (RBS). Various methods of Chromatography are also used, as well as thermogravimetric analysis.
While arginine, glutamine and other amino acids are rapidly consumed often very early in fermentation, proline is not consumed by yeast at all during the normal, anaerobic conditions of fermentations. This is because one of the enzymes required for its use is an oxidase (requiring molecular oxygen) and the other is repressed by the presence of ammonium (another source of assimilable nitrogen needed by yeast) in the must. However, well aerated starter cultures that contain must which hasn't had any diammonium phosphate added it to it will usually see some utilization of proline before the anaerobic conditions of fermentation kick in. When winemakers measure FAN, they need to be aware if their assay is including proline since this will make their YAN measurement higher. Chardonnay and Cabernet Sauvignon are two Vitis vinifera varieties that are known to have very high proline levels while Riesling and Sauvignon blanc usually have very low levels. Yeast transport amino acids and small peptides (less than 5 amino acid residues) into the cell via an active transport process that utilizes specialized membrane proteins and the difference in the pH gradient of the acidic wine solution (pH between 3-4) and the near neutral pH of cytoplasm inside the yeast cells. The proton symport proteins in the membrane take in the amino acid coupled with a hydrogen ion that later gets expelled by the cell via a hydrogen ion pump.
Sources: en.wikipedia.org
The shadow exists as part of the unconscious mind and is composed of the traits individuals instinctively or consciously resist identifying as their own and would rather ignore, typically repressed ideas, weaknesses, desires, instincts, and shortcomings. Much of the shadow comes as a result of an individual's adaptation to cultural norms and expectations. Thus, this archetype not only consists of all the things deemed unacceptable by society but also those things that are not aligned with one's own personal morals and values. Jung argued that each person has a desire to keep their shadow hidden under what he called the moral complex (equivalent to Freud's super-ego) and that this is the impetus for humans to learn and maintain the values of our cultures. The shadow can often appear as a dark, wild, exotic figure in dreams or visions. Jung argues that the shadow plays a distinctive role in balancing one's overall psyche, the counter-balancing to consciousness—"where there is light, there must also be shadow". In order to truly grow as an individual, Jung believed that both the persona and shadow should be balanced. Without a well-developed shadow (often "shadow work", "integrating one's shadow"), an individual can become shallow and extremely preoccupied with the opinions of others; that is, a walking persona. Not wanting to look at their shadows directly, Jung argues, often results in psychological projection. Individuals project imagined attitudes onto others without awareness.
=== Green algal derived chloroplasts === Green algae have been taken up by many groups in three or four separate events. Primarily, secondary chloroplasts derived from green algae are in the euglenoids and chlorarachniophytes. They are also found in one lineage of dinoflagellates and possibly the ancestor of the CASH lineage (cryptomonads, alveolates, stramenopiles and haptophytes) Many green algal derived chloroplasts contain pyrenoids, but unlike chloroplasts in their green algal ancestors, storage product collects in granules outside the chloroplast.
=== Transamination === Urea undergoes transamination. For example, treatment with anilinium gives both N-phenylurea and N,N'-diphenylurea. N-Methylurea can be prepared by a similar acid-catalyzed pathway.
===== Iron recycling and loss ===== Most of the iron in the body is hoarded and recycled by the reticuloendothelial system, which breaks down aged red blood cells. In contrast to iron uptake and recycling, there is no physiologic regulatory mechanism for excreting iron. People lose a small but steady amount by gastrointestinal blood loss, sweating and by shedding cells of the skin and the mucosal lining of the gastrointestinal tract. The total amount of loss for healthy people in the developed world amounts to an estimated average of 1 mg a day for men, and 1.5–2 mg a day for women with regular menstrual periods. People with gastrointestinal parasitic infections, more commonly found in developing countries, often lose more. Those who cannot regulate absorption well enough get disorders of iron overload. In these diseases, the toxicity of iron starts overwhelming the body's ability to bind and store it.
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.
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.