Lyophilisation comes up often in conversation and rarely with the context attached. Here we lay out the basics in order, then work through the practical considerations.
Last reviewed on 2025-11-13. Where a claim depends on a specific study, the study is described rather than over-claimed.
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 has a calculated molecular weight near 751.9 daltons and carries a net positive charge at physiological pH because of its arginine residue. It dissolves freely in water and in common aqueous buffers, and typically appears as a white or off-white lyophilized powder. The amide backbone makes the molecule susceptible to peptidases, which limits oral use and favors intranasal or parenteral routes. Nomenclature in the literature varies: the substance is also described by the sequence abbreviation TP-7 and by a Russian trade designation.
Pharmacokinetic data are limited. Like most short peptides, Selank is vulnerable to plasma and tissue peptidases, and its measured half-life in circulation is short, on a minutes scale. The Pro-Gly-Pro tail slows this degradation but does not eliminate it. Intranasal administration is the route described in most reports, with absorption through the nasal mucosa and a hypothesized path into the central nervous system that avoids the blood-brain barrier. Direct measurements of human brain exposure are unavailable, so distribution claims rest on inference from animal work.
Clinical evidence comes mainly from small studies conducted in Russia, several of which were open-label or lacked robust blinding. Reported outcomes include lower anxiety scores, changes in attention measures, and effects on asthenic states following illness. Sample sizes are typically in the tens of participants, and independent replication outside the region is scarce. Reviews published in English generally note the limited methodological quality of the underlying trials. Whether the compound produces clinically meaningful effects under rigorous conditions remains unresolved.
| Property | Value | Notes |
|---|---|---|
| Chemical class | Synthetic heptapeptide | Analog of the tetrapeptide tuftsin |
| Sequence | Thr-Lys-Pro-Arg-Pro-Gly-Pro | Reported consistently across pharmacopoeial descriptions |
| Appearance | White to off-white lyophilized powder | Typical form of research-grade material |
| Solubility | Freely soluble in water | Aqueous buffers; poor in nonpolar solvents |
| Typical storage temperature | -20 degrees Celsius | Lyophilized powder; protect from moisture |
Selank is a synthetic heptapeptide developed in Russia. Its sequence is Thr-Lys-Pro-Arg-Pro-Gly-Pro, a seven-residue chain built around the natural tetrapeptide tuftsin. Researchers at the Institute of Molecular Genetics of the Russian Academy of Sciences first described the compound in the mid-1990s. The design combined the tuftsin core with an added Pro-Gly-Pro tail, a modification intended to extend the molecule's stability in biological fluids. Published work on the peptide has appeared mainly in Russian-language journals.
Reported activity for Selank centers on anxiolytic and nootropic effects. Russian clinical reports describe use in anxiety and in cognitive or attention-related complaints. Most of this evidence comes from studies conducted by the same research groups that developed the peptide. Independent replication in other countries remains limited, and no major Western regulatory agency has approved the compound for any indication. The gap between local reports and external verification is a recurring point in discussions of the peptide.
Tuftsin, the parent structure, is a naturally occurring immunomodulatory tetrapeptide released from the Fc region of immunoglobulin G by spleen enzymes. Selank extends this four-residue sequence with three additional amino acids. The stated rationale is that the added tail slows enzymatic breakdown and may influence receptor interactions. How the full heptapeptide behaves at the molecular level is not firmly established, and proposed mechanisms often involve indirect modulation of neurotransmitter or immune signaling rather than a single defined target.
Dry powder is normally held at -20 degrees Celsius or lower, in a sealed container with desiccant and protection from light. Reconstituted solutions are usually kept at 2 to 8 degrees Celsius for short periods and frozen for longer ones. Proline residues at several positions are generally associated with some resistance to peptidase attack, but chemical stability still declines at neutral to alkaline pH and at elevated temperature. Exact shelf-life figures are product-specific and are not standardised across suppliers.
Identity and purity are usually assessed by reversed-phase high-performance liquid chromatography, with mass spectrometry used to confirm molecular mass and sequence information. Amino acid analysis and peptide mapping may supplement these methods. Certified reference standards are scarce, and many commercial lots are sold as research chemicals without a pharmacopoeial monograph. Regulatory treatment differs by country: Selank is a registered prescription medicine in Russia, while in the European Union and the United States it is not an approved drug and may fall under research-chemical or unapproved-product frameworks.
Selank is a hydrophilic peptide and dissolves readily in water and in aqueous buffers. The lyophilised powder is typically a white to off-white solid. Because short peptides are prone to hydrolysis and oxidation, handling benefits from limiting exposure to heat, moisture and strong light. Working solutions are commonly prepared in sterile water or saline, and repeated freeze-thaw cycles are avoided to reduce aggregation and loss of activity. These practices reflect general laboratory convention rather than published stability specifications.
So it was proposed that succinyl amino acid derivative should be an ACE inhibitor and succinyl-L-proline was found to be such an inhibitor. It was also known that the nature of penultimate amino acid residue of a peptide substrate for ACE influences binding to the enzyme. The acyl group of the carboxyalkanoyl amino acid binds the zinc ion of the enzyme and occupies the same position at the active site of ACE as the penultimate. Therefore, the substituent of the acyl group might also influence binding to the enzyme. A 2-methyl substituent with D configuration was found to enhance the inhibitory potency by about 15 fold of succinyl-L-proline. Then the search for a better zinc-binding group started. Replacement of the succinyl carboxyl group by nitrogen-containing functionalities (amine, amide or guanidine) did not enhance inhibitory activity. However a potency breakthrough was achieved by the replacement of the carboxyl group with a sulfhydryl function (SH), a group with greater affinity for the enzyme bound zinc ion. This yielded a potent inhibitor that was 1000 times more potent than succinyl-L-proline. The optimal acyl chain length for mercaptoalkanoyl derivates of proline was found to be 3-mercaptopropanoyl-L-proline, 5 times greater than that of 2-mercaptoalkanoyl derivates and 50 times greater than that of 4-mercaptoalkanoyl derivates. So the D-3-mercapto-2-methylpropanoyl-L-proline or Captopril was the most potent inhibitor.
=== Conceptual development === Ilyushin began work on the aerobus in late 1969, initially by assessing the development potential of existing aircraft. An enlarged Il-62 (the Il-62-250) would have had a 30-tonne payload, 259 seats and a 6.8 metre/22 ft longer fuselage: a virtual analogue of the Douglas DC-8 "Super Sixty" series. Other proposed Il-62 modifications involved double-deck and "two fuselages side-by-side" developments. There was also a project to "civilianise" the Il-76. From March 1970 the bureau developed all-new designs under the Il-86 designation. Instead of the "appropriate technology" approach of the Il-62, these designs were to have powered controls, complex high-lift devices and advanced automation which would reduce the number of flightdeck crew. An early avanproyekt was shown to the Soviet leadership at an exhibition of civil aviation innovations at Vnukovo-2 Airport near Moscow on May 17, 1971. A scale model with the designation of "Il-86" showed the "self-loading" concept with integral boarding stairs, below-deck luggage stores, and below-deck midships galley. It had a twin-aisle interior with nine-abreast seating in a "3–3–3" layout. Ilyushin considered it politic to make the interior wider than any planned airliner except the Boeing 747. The 6.07 m (19.9 ft) fuselage diameter was partly dictated by the need to provide standing room in the underfloor luggage compartments. The Il-86 had the second-widest fuselage of any airliner until the Boeing 777. On this basis, on 9 March 1972, the bureau was asked to proceed with detailed design.
Arabinogalactan-proteins (AGPs) are highly glycosylated proteins (glycoproteins) found in the cell walls of plants. Each one consists of a protein with sugar molecules attached (which can account for more than 90% of the total mass). They are members of the wider class of hydroxyproline (Hyp)-rich cell wall glycoproteins, a large and diverse group of glycosylated wall proteins. AGPs have been reported in a wide range of higher plants in seeds, roots, stems, leaves and inflorescences. AGPs account for only a small portion of the cell wall, usually no more than 1% of dry mass of the primary wall. They have also been reported in secretions of cell culture medium of root, leaf, endosperm and embryo tissues, and some exudate producing cell types such as stylar canal cells are capable of producing lavish amounts of AGPs. They are implicated in various aspects of plant growth and development, including root elongation, somatic embryogenesis, hormone responses, xylem differentiation, pollen tube growth and guidance, programmed cell death, cell expansion, salt tolerance, host-pathogen interactions, and cellular signaling. AGPs have attracted considerable attention due to their highly complex structures and potential roles in signalling. In addition, they have industrial and health applications due to their chemical/physical properties (water-holding, adhesion and emulsification).
These require urgent assessment for rhabdomyolysis as in about 30% of cases this leads to acute kidney injury, which left untreated can be life-threatening. In a small number of cases compartment syndrome has developed, requiring prompt surgical referral.
Sources: en.wikipedia.org
LRP1 is also continuously endocytosed from the membrane and recycled back to the cell surface. Though the role of LRP1 in apoptosis is unclear, it is required for tPA to bind LRP1 in order to trigger the ERK1/2 signal cascade and promote cell survival.
This was intended to demonstrate Rhodesia's continued loyalty to the Queen, but the use of the unmistakably British song at Rhodesian state occasions soon seemed "fairly ironic", as The Times put it. Salisbury started looking for a replacement anthem around the same time as its introduction of the new flag, and in 1974, after four years without an anthem ("God Save the Queen" was formally dropped in 1970), republican Rhodesia adopted "Rise, O Voices of Rhodesia", an anthem coupling original lyrics with the tune of Beethoven's "Ode to Joy". The country's head of state under the republican constitution was the President of Rhodesia, the first of whom was Dupont. State press censorship, which had been introduced on UDI, was lifted in early April 1968. Decimalisation occurred on 17 February 1970, two weeks before Rhodesia's reconstitution as a republic, with the new Rhodesian dollar replacing the pound at a rate of two dollars to each pound. Following the republic's formal declaration the next month, the Rhodesian military removed nomenclatural and symbolic references to the Crown—the Royal Rhodesian Air Force and Royal Rhodesia Regiment dropped their "Royal" prefixes after the Queen formally revoked them because of the declaration, new branch and regimental flags were designed, and the St Edward's Crown surmounting many regimental emblems was expunged in favour of the "Lion and Tusk", a motif from the coat of arms of the British South Africa Company that had been used in Rhodesian military symbolism since the 1890s.
== Products == The company is known for its Original Ice Blended coffee and tea drinks, hot coffee drinks, and hot and iced tea drinks. It also sells a variety of whole bean coffees, whole leaf teas, flavored powders, and baked goods.
Sources: en.wikipedia.org
== First Ministry == On 29 June 1998, a full ministry of 18 cabinet ministers and 4 parliamentary secretaries was sworn in. It served until the reconstitution of the Ministry on 22 February 2001 following the 2001 election. The list below is ordered by decreasing seniority within the Cabinet, as indicated by the Government Gazette and the Hansard index.
== Side effects == Bone marrow suppression (anemia, neutropenia, thrombocytopenia) is the most commonly occurring side effect of chlorambucil. Withdrawn from the drug, this side effect is typically reversible. Like many alkylating agents, chlorambucil has been associated with the development of other forms of cancer. Less commonly occurring side effects include:
La Resistencia (The Resistance) is a right-wing decentralized group that opposes the Castillo Administration. The group has been behind threats of harassment, verbal assaults, and physical attacks on citizens and government officials. La Resistencia has accused their opponents of being terrorists and Senderistas. Following repeated threats against the former supreme prosecutor Avelino Guillén and the journalist Jaime Chincha, the Ministry of the Interior has ordered an investigation into the alleged criminal organization. On 7 October 2021, approximately ten members of La Resistencia assaulted a car which had journalists inside. The car had stopped due to a red light, which the group took advantage of by repeatedly hitting the car's windows and insulting its passengers. The journalists managed to escape, but the car was battered. On 18 October 2021, members of La Resistencia interrupted the initial book sale of "Imagine a better Peru... and let's make it happen." by former President Francisco Sagasti and blocked the doorways as to prevent people from leaving. There were shouts against Sagasti, decrying him as a "murderer" and a "terrorist." Previously, Sagasti had gotten backlash from proponents that there was electoral fraud in the 2021 Peruvian general election, due to him repeatedly denying that fraud took place and handing the presidency to Castillo. On 8 November 2021, the Interior Ministry claimed that groups consisting of ex-military and ex-police personnel are appearing, many of whom being veterans of the war against the Shining Path.
Structural similarities between acetyl-CoA and malonyl-CoA suggest that certain lysine acetyltransferases (KATs) may also catalyze malonylation. KAT2A (GCN5) has been experimentally linked to histone malonylation and is currently the strongest candidate, while p300 has also been proposed and is known to mediate other acyl modifications such as crotonylation. Analogous to the GCN5 acetylation mechanism, the ε-amino group is thought to be transiently deprotonated by a catalytic base within the enzyme's active site, thereby enabling the same reaction with malonyl-CoA as in non-enzymatic malonylation. However, specific enzymes known as malonyltransferases have not yet been definitively identified. The demalonylation is catalyzed by the enzyme Sirtuin 5 (SIRT5), a class III histone deacetylase that requires NAD+ for activity but is inhibited by nicotinamide. SIRT5 is globally expressed in mitochondrial, cytoplasmic, and nuclear compartments, and can also remove other negatively charged acyl modifications. It catalyzes the demalonylation in the following reaction:
Sources: en.wikipedia.org
Selank is a synthetic seven-amino-acid peptide modeled on tuftsin, a fragment of the immunoglobulin G heavy chain. It was designed in Russia to combine anxiolytic and immunomodulatory properties in one molecule.
The first four residues of Selank reproduce the tuftsin sequence Thr-Lys-Pro-Arg. A Pro-Gly-Pro extension at the C-terminus was added to slow enzymatic breakdown and extend residence time.
It holds marketing authorization in Russia, where nasal drop formulations are sold. No equivalent approval exists in the European Union, the United States, or most other countries.
Reports describe effects on GABA-A receptor expression, monoamine turnover, and neurotrophic factor levels. These are proposed mechanisms drawn mainly from animal models. No single molecular target has been established.