This is a working overview of lyophilization, written for readers who want more than a one-paragraph summary but less than a textbook.
Reviewed 2025-12-27. Anything still debated is marked as such rather than presented as settled.
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.
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.
Enzymatic stability motivates the extra three residues at the carboxyl end. Native tuftsin is cleaved quickly by circulating aminopeptidases and carboxypeptidases, which limits its duration of action and its usefulness as a tool compound. Extending the chain with proline-rich segments is a common design tactic because proline constrains the backbone and slows proteolysis. The same Pro-Gly-Pro motif appears in other Russian-developed peptides of the era. Whether the full seven-residue chain is required for activity, or whether it acts mainly as a prodrug releasing tuftsin, remains unresolved.
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 |
|---|---|---|
| Dry storage temperature | -20 C or below | Sealed, desiccated, protected from light |
| Solution stability | Hours to days at 2-8 C | Depends on buffer and microbial load |
| Preferred pH range | Near neutral to slightly acidic | Alkaline pH accelerates hydrolysis |
| Main degradation routes | Hydrolysis and deamidation | No cysteine or methionine in sequence |
| Identity confirmation | Electrospray mass spectrometry | Observed mass compared with 751.9 Da |
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.
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.
Regulatory status differs sharply by region. Selank holds a Russian marketing authorization, where it is supplied mainly as nasal drops, while authorities elsewhere have not approved it for medical use. Material sold internationally is therefore usually labeled as a research chemical rather than a medicine. Peer-reviewed publications come predominantly from Russian laboratories, and sample sizes are generally small. Whether the compound produces comparable effects under independent, well-controlled replication remains an open question that the broader literature has not settled.
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.
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.
On 18 January 2024, Natalia Kanem, the executive director of the UN Population Fund, spoke at the World Economic Forum at Davos, stating the situation was the "worst nightmare" the UNPF representative had ever witnessed, as there were 180 women giving birth daily, sometimes on the streets of Gaza, as the territory's health system collapsed. On 17 January, Care International reported a 300 percent increase in the rate of miscarriage in Gaza since the start of Israel's bombing. UNICEF reported on 19 January that 20,000 babies had been born in the Gaza Strip since 7 October. UNICEF described each birth as a baby being "delivered into hell", and stated "humanity cannot allow this warped version of normal to persist any longer." The UN Women's agency reported that since the start of the conflict, two mothers in Gaza had been killed every hour, every day. WHO reported an increase in stress-induced stillbirths. Doctors Without Borders stated that women were giving birth in plastic tents, and that those undergoing C-sections were being released within hours. It also reported that women were being turned away from hospitals due to overcrowding, with some forced to birth in public restrooms. Doctors at Kamal Adwan Hospital performed an emergency c-section on a deceased pregnant woman in February 2024, after which they performed a fetal cardiac resuscitation; however, the baby did not survive.
In fact, John Zhu, a professor at the University of Queensland, is exploring the creation of a carbon nanotube(CNT) which can trap greenhouse gases hundreds of times more efficiently than current methods can.
The Crick Papers at the Wellcome Trust. "Quiet debut for the double helix" by Professor Robert Olby, Nature 421 (23 January 2003): 402–405. Reading list for discovery of DNA story from the National Centre for Biotechnology Education. Papers of Francis Crick, 1953–1969 held at Churchill Archives Centre About his life
25499Es + 4820Ca → 302119Uue* → no atoms It is highly unlikely that this reaction will be able to create any atoms of ununennium in the near future, given the extremely difficult task of making sufficient amounts of einsteinium-254, which is favoured for production of ultraheavy elements because of its large mass, relatively long half-life of 270 days, and availability in significant amounts of several micrograms, to make a large enough target to increase the sensitivity of the experiment to the required level; einsteinium has not been found in nature and has only been produced in laboratories, and in quantities smaller than those needed for effective synthesis of superheavy elements. However, given that ununennium is only the first period 8 element on the extended periodic table, it may well be discovered in the near future through other reactions, and indeed an attempt to synthesise it is currently ongoing in Japan. Currently, none of the period 8 elements has been discovered yet, and it is also possible, due to drip instabilities, that only the lower period 8 elements, up to around element 128, are physically possible. No attempts at synthesis have been made for any heavier alkali metals: due to their extremely high atomic number, they would require new, more powerful methods and technology to make.
The following table illustrates variability in reference ranges of serum prolactin between some commonly used assay methods (as of 2008), using a control group of healthy health care professionals (53 males, age 20–64 years, median 28 years; 97 females, age 19–59 years, median 29 years) in Essex, England: An example of the use of the above table is, if using the Centaur assay to estimate prolactin values in μg/L for females, the mean is 168 mIU/L (7.92 μg/L) and the reference range is 71–348 mIU/L (3.35–16.4 μg/L). Hyperprolactinaemia, or excess serum prolactin, is associated with hypoestrogenism, anovulatory infertility, oligomenorrhoea, amenorrhoea, unexpected lactation and loss of libido in women and erectile dysfunction and loss of libido in men. Causes of Elevated Prolactin Levels
Sources: en.wikipedia.org
207Pb is the end of the actinium series from 235U. 208Pb is the end of the thorium series from 232Th. While it only makes up approximately half of the composition of lead in most places on Earth, it can be found naturally enriched up to around 90% in thorium ores. 208Pb is the heaviest known stable nuclide and also the heaviest known doubly magic nucleus, as Z = 82 and N = 126 correspond to closed nuclear shells. As a consequence of this particularly stable configuration, its neutron capture cross section is very low (even lower than that of deuterium in the thermal spectrum), making it of interest for lead-cooled fast reactors. In 2025 a published study suggested that the nucleus of 208Pb is not perfectly spherical as previously believed, but rather is a "prolate spheroid", more commonly described as the shape of a rugby ball.
1921 Research on the role of pancreas in the nutritive assimilation 1922 Frederick Banting, Charles Best and James Collip use bovine insulin extract in humans at Connaught Laboratories in Toronto, Canada. 1922 Leonard Thompson becomes the first human to be treated with insulin. 1922 James D. Havens, son of former congressman James S. Havens, becomes the first American to be treated with insulin. 1922 Elizabeth Hughes Gossett, daughter of the US Secretary of State, becomes the first American to be (officially) treated in Toronto. 1923 Dr. Trent Champion de Crespigny delivers the first treatments with insulin produced in Australia, to a 9-year-old, in Adelaide, South Australia, on 7 January 1923. 1923 Eli Lilly produces commercial quantities of much purer bovine insulin than Banting et al. had used 1923 Farbwerke Hoechst, one of the forerunners of today's Sanofi Aventis, produces commercial quantities of bovine insulin in Germany 1923 Hans Christian Hagedorn founds the Nordisk Insulinlaboratorium in Denmark – forerunner of today's Novo Nordisk 1923 Constance Collier returns to health after being successfully treated with insulin in Strasbourg 1924 Margaret Cheadle, a research biochemist in the laboratory of T. Brailsford Robertson at the University of Adelaide, determined that approx. 167 "mouse units" of insulin were "equivalent to one two-kilogram rabbit-unit". 1926 Nordisk receives a Danish charter to produce insulin as a non-profit 1936 Canadians David M. Scott and Albert M.
==== VGluT3 ==== VGluT3 (Vesicular Glutamate Transporter 3) that is encoded by the SLC17A8 gene is a member of the vesicular glutamate transporter family that transports glutamate into the cells. It is involved in neurological and pain diseases. Neurons are able to express VGluT3 when they use a neurotransmitter different to Glutamate, for example in the specific case of central 5-HT neurons. The role of this unconventional transporter (VGluT3) still remains unknown but, at the moment, has been demonstrated that, in auditory system, the VGluT3 is involved in fast excitatory glutamatergic transmission very similar to the other two vesicular glutamate transporters, VGluT1 and VGluT2. There are behavioral and physiological consequences of VGluT3 ablation because it modulates a wide range of neuronal and physiological processes like anxiety, mood regulation, impulsivity, aggressive behavior, pain perception, sleep–wake cycle, appetite, body temperature and sexual behavior. Certainly, no significant change was found in aggression and depression-like behaviors, but in contrast, the loss of VGluT3 resulted in a specific anxiety-related phenotype. The sensory nerve fibers have different ways to detect the pain hypersensivity throughout their sensory modalities and conduction velocities, but at the moment is still unknown which types of sensory is related to the different forms of inflammatory and neuropathic pain hypersensivity.
== Honors and awards == 1981–1982: Fogarty International Scholar 1981: Honorary Member of the American Society of Biological Chemistry 1984: Rothschild Prize in Chemistry 1987: Wolf Prize in Medicine, jointly with Pedro Cuatrecasas, "for the invention and development of affinity chromatography and its applications to biomedical sciences." 1987: Pierce Prize for Biorecognition Technology 1988: Elected Member of the Israel Academy of Sciences and Humanities 1989: Doctor of Science, honoris causa, University of Waterloo, Canada 1989: Barnett Lecturer, Northeastern University, Boston 1990: Israel Prize, in life sciences 1990: Sarstedt Prize (Numbrecht, Germany) 1993: Foreign Associate Member, Institute of Medicine, National Academy of Science, USA 1995: Doctor of Science, honoris causa, Bar Ilan University, Israel 1996: International Distinguished Clinical Chemist Award, International Federation of Clinical Chemistry (IFCC) 2000: Doctor of Science, honoris causa, University Jyvaskyla, Finland 2000: Honorary Doctorate, Ben-Gurion University of the Negev 2002: Honorary Citizen, City of Rehovot, Israel 2004: Wilhelm Exner Medal. 2004: Christian B. Anfinsen Award of The Protein Society 2004: Wilhelm-Exner Medal, OGV, President of Austria 2005: Emet Prize, presented by the Prime Minister of Israel
=== United Kingdom === Lycium barbarum had been introduced in the United Kingdom in the 1730s by The Duke of Argyll, but the plant was mostly used for hedges and decorative gardening. The UK Food Standards Agency (FSA) had initially placed goji berry in the Novel Foods list. That classification would have required authorisation from the European Council and Parliament for marketing. However, on 18 June 2007, the FSA concluded that there was a significant history of consumption of the fruit before 1997, indicating its safety, and thus removed it from the list.
Sources: en.wikipedia.org
Dry powder is best kept sealed, protected from light, and held at minus 20 degrees Celsius or below. Desiccant packaging helps limit moisture uptake because the material is hygroscopic. A sealed vial should be allowed to equilibrate to room temperature before opening to reduce condensation.
Hydrolysis of peptide bonds and deamidation of arginine and proline residues are the main degradation routes. Alkaline pH and higher temperatures accelerate both processes. Buffered, near-neutral solutions stored cold generally degrade more slowly than unbuffered ones.
Reverse-phase chromatography gives the clearest single view of related impurities and truncated sequences. Mass spectrometry then confirms that the main peak carries the expected mass. Neither test detects enantiomeric impurities, which require a separate chiral assay.
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.