This is a working overview of lyophilisation, written for readers who want more than a one-paragraph summary but less than a textbook.
This page was last updated on 2025-12-13 and is reviewed periodically as new material appears.
The compound is described in the literature as a derivative of epithalamin, a preparation obtained from bovine pineal tissue. Work on this peptide family was carried out mainly by a research group in Saint Petersburg beginning in the 1980s, and the substance was later registered for clinical use in Russia under the name Epitalon. Outside that region it is generally treated as a research chemical rather than an approved medicine. Statements about its biological activity rest on a relatively small number of studies, and independent replication remains limited.
In its supplied form epitalon is a white to off-white powder, usually lyophilized and often hygroscopic. It dissolves readily in water and in aqueous buffers, and it is commonly handled as the acetate or trifluoroacetate salt to improve stability during purification and drying. The amide backbone is labile in aqueous media, so solutions are less durable than the dry solid. Handling notes in the chemical literature therefore emphasize keeping the powder dry, cool and shielded from light until it is dissolved.
Epitalon is a synthetic tetrapeptide whose sequence is alanine-glutamate-aspartate-glycine, written in single-letter code as AEDG. The four residues are joined by three peptide bonds, giving a linear backbone with no branching and no disulfide bridges. Its calculated molecular mass for the free form is approximately 390.3 daltons, a figure that rises when the compound is supplied as an acetate or trifluoroacetate salt. Because the chain is short, the molecule is defined entirely by its residue order rather than by any folded three-dimensional structure.
Identity and purity are established with reversed-phase high-performance liquid chromatography and mass spectrometry. The chromatogram shows the main peak and any truncated or oxidised by-products, while the mass spectrum confirms the expected 390 dalton mass. Amino acid analysis can corroborate composition when a sample's origin is uncertain. Counterion content, particularly residual trifluoroacetate from purification, is frequently reported alongside purity because it shifts the net mass of the solid.
Reference material is normally supplied as a lyophilised powder in a sealed vial. Product literature typically recommends storage at minus twenty degrees Celsius or colder, protected from light and moisture. Freeze-thaw cycling is usually avoided because repeated condensation can introduce water into the vial. Working solutions are commonly prepared fresh, aliquoted, and kept cold for short periods rather than stored at ambient temperature. Labelling the date of opening helps track how long a vial has been in use.
| Property | Value | Notes |
|---|---|---|
| Chemical class | Synthetic tetrapeptide | Four residues, linear chain |
| Residue sequence | Ala-Glu-Asp-Gly | Single-letter form AEDG |
| Calculated mass | 390.3 daltons | Value for the free, uncharged form |
| Appearance | White to off-white powder | Usually supplied lyophilized |
| Solubility | Freely soluble in water | Often handled as a salt form |
Epitalon is a synthetic tetrapeptide with the residue sequence alanine-glutamate-aspartate-glycine, commonly abbreviated AEDG. Its monoisotopic mass is approximately 390.35 daltons, and it is usually supplied as a lyophilised trifluoroacetate or acetate salt. The compound was derived from a pineal gland extract called epithalamin, a heterogeneous preparation investigated in the former Soviet Union. Researchers associated with the Saint Petersburg Institute of Bioregulation and Gerontology described the tetrapeptide as a constituent fragment of that extract. Commercial material is offered as a laboratory reagent rather than as a finished pharmaceutical product.
Literature searches for this compound must account for several spelling variants. Indexing databases contain epitalon, epithalon, epithalone, and AEDG, and relevant records are scattered across Russian-language and English-language journals that do not consistently cross-cite. Early publications describe the parent extract as a mixture of many peptides, whereas later work addresses the single synthetic tetrapeptide. That shift in nomenclature complicates comparison between studies, because extract data and tetrapeptide data are sometimes cited interchangeably. A search strategy omitting the alternate spellings will return an incomplete set of references.
Regulatory treatment differs by country. No formulation of epitalon holds a marketing authorisation as a medicine in the United States or the European Union, where material sold for laboratory use is handled as a research chemical and is not intended for human consumption. In Russia, several short peptide preparations from the same institute's peptide series are registered medicinal products, and epitalon appears in that national context. Elsewhere it is frequently offered as a cosmetic ingredient, a category with lighter requirements. Advertising claims about longevity or disease prevention are restricted in most jurisdictions, which limits how sellers describe the compound.
Freeze-dried epitalon is normally kept at minus twenty degrees Celsius in a sealed, desiccated container, protected from light. Short excursions at ambient temperature during shipping are generally tolerated, but repeated warming and cooling cycles encourage moisture uptake, which shortens shelf life. Once dissolved, the peptide is far less stable than the solid: aqueous solutions are subject to hydrolysis and to deamidation at the aspartate and glutamate residues. Working solutions are therefore held refrigerated and used within days, and repeated freezing and thawing of the same vial is best avoided.
Epitalon is a synthetic tetrapeptide with the amino acid sequence alanine-glutamate-aspartate-glycine, abbreviated Ala-Glu-Asp-Gly or AEDG. It was developed by the Russian researcher Vladimir Khavinson and colleagues during work on peptide bioregulators derived from the pineal gland. The compound is short enough to be produced by standard solid-phase peptide synthesis and is typically handled as a lyophilized white powder. Its small size distinguishes it from larger pineal peptides such as epithalamin, a complex extract from which the tetrapeptide was conceptually derived.
The four residues give epitalon a molecular formula of C14H22N4O9 and a molecular weight near 390.35 daltons. The presence of two acidic residues, glutamate and aspartate, makes the free peptide strongly acidic, while the alanine and glycine ends provide neutral, nonpolar character. This combination produces a molecule with substantial water solubility. Because there are no cysteine, methionine, or tryptophan residues, the peptide lacks the most common oxidation-sensitive side chains, which simplifies handling compared with many longer peptides.
Verification of research-grade material involves comparing a supplier chromatogram against an in-house reference, checking the observed mass against the calculated value, and where possible confirming residue order by tandem mass spectrometry or enzymatic peptide mapping. Purity claims should be read alongside the method used to obtain them, because detection wavelength and integration settings alter the result. Batch-specific data, rather than a generic grade statement, is the informative part of a certificate.
Identity and purity of epitalon samples are normally established by reversed-phase high-performance liquid chromatography with ultraviolet detection near 214 nanometres, combined with mass spectrometry. The mass spectrum confirms the expected molecular ion and can reveal truncated or oxidised by-products. Amino acid analysis after acid hydrolysis verifies that the four residues are present in the expected ratio. Certificates typically report a purity figure taken from chromatographic peak area, expressed as a percentage of total integrated signal.
Anti-submarine net Boom defence vessel - a vessel charged with laying anti-submarine nets Log boom - a boom for collecting logs Boom (containment) - a boom for containing oil spills Pile barrage - an underwater fortification consisting of piles driven into the sea or river bed
=== As feed === The larvae of the litter beetle, like certain other larvae of darkling beetles such as mealworms, are used as animal feed, e.g., fed to captive reptiles. They have been reported as a good first food for Central American wood turtle (Rhinoclemmys pulcherrima mannii) hatchlings, because they are more active than common mealworms and their movement stimulates feeding behavior.
=== Chromatographic processes === The theoretical plate concept was also adapted for chromatographic processes by Martin and Synge. The IUPAC's Gold Book provides a definition of the number of theoretical plates in a chromatography column. The same equation applies in chromatography processes as for the packed bed processes, namely:
Mulligan (Larry Friedman), the leader; occasionally plays guitar Maggie (Sherry Wright), identified by her long blond pigtailed hair; keyboards Mike (Steven Einbender), an Italian; drums Manny (Benjamin Sands), a Black preteen; bass Micki (Mi-On Hahm), a young Asian girl; guitar (Mulligan, Maggie and Micki all sing lead vocals on most of the band's songs while Mike and Manny usually handle backing vocals.) The group's clubhouse is a basement in a brownstone apartment, fully furnished with a kitchen, shortwave radio, home gym, laboratory, and even a small stage where they rehearse their music. Their grownup advisor and mentor is Wilbur Dooright (Barry Michlin), a bespectacled, bumbling accountant who, in some episodes, gives the kids their assignments "from upstairs", assumed to be a secret government organization (paying homage to the spy films and TV shows of the day). Wilbur provides much of the comic relief throughout the series.
== Contraindications == Women who are or who may become pregnant should not handle the drug. Dutasteride can cause birth defects in male fetuses, specifically ambiguous genitalia and undermasculinization. This is due to its antiandrogenic effects similar to what is seen in 5α-reductase deficiency. For the same reason, women who are currently pregnant should never take dutasteride. People taking dutasteride should not donate blood to prevent birth defects if a pregnant woman receives blood and should also not donate blood for at least 6 months after the cessation of treatment due to the drug's long elimination half-life. Children and people with known significant hypersensitivity (e.g., serious skin reactions, angioedema) to dutasteride should not take it.
Sources: en.wikipedia.org
Type 1: Separate hard lumps, like nuts (difficult to pass) Type 2: Sausage-shaped, but lumpy Type 3: Like a sausage but with cracks on its surface Type 4: Like a sausage or snake, smooth and soft (average stool) Type 5: Soft blobs with clear cut edges Type 6: Fluffy pieces with ragged edges, a mushy stool (diarrhoea) Type 7: Watery, no solid pieces, entirely liquid (diarrhoea) Types 1 and 2 indicate constipation, with 3 and 4 being the ideal stools as they are easy to defecate while not containing excess liquid, and 6 and 7 indicate diarrhoea. Some media describe type 4 as "ghost poop" or "perfect poop". In the initial study, in the population examined in this scale, the type 1 and 2 stools were more prevalent in females, while the type 5 and 6 stools were more prevalent in males; furthermore, 80% of subjects who reported rectal tenesmus (sensation of incomplete defecation) had type 7. These and other data have allowed the scale to be validated. The initial research did not include a pictorial chart with this being developed at a later point. The Bristol stool scale is also very sensitive to changes in intestinal transit time caused by medications, such as antidiarrhoeal loperamide, senna, or anthraquinone with laxative effect.
== Management == BACM may be alarming to parents and lead to unnecessary extensive tests. Treatment consists of oral analgesics, rest, and adequate hydration. Hospitalization is usually not necessary. Full recovery can be expected within a week, however, recurrences can occur.
September 18 Russia and China veto a US proposal for UN experts to continue monitoring UN sanctions on Iran over its nuclear program. The US sentences a Syrian national who fraudulently immigrated to the country and served as the former head of the notorious Adra Prison under former Syrian president Bashar al-Assad to 60 years imprisonment on torture charges. Trump bans CNN, MS NOW, and Politico from the White House, accusing them of spreading "fake news." Greenland crisis: The United States, Denmark and Greenland announce an agreement to strengthen security in the Arctic and North Atlantic, expanding the permanent U.S. military presence in Greenland while recognising Danish sovereignty and Greenlandic self-determination. The agreement follows months of threats by President Trump to acquire or annex Greenland. September 19 The Trump administration approves a potential $2.68 billion sale of air defense equipment to Ukraine, adding that the country would finance it using a combination of European contributions and US foreign military financing. Trump signs the "Lindsey O Graham Sanctioning Russia and Iran Act of 2026," which allows him to impose tariffs of up to 100 percent on Russian oil buyers, including China and India, in response to the country's war in Ukraine, as well as to extend existing sanctions on Iran. The United States Southern Command states that its strike on a vessel in the Caribbean killed four people, adding that confirmed intelligence indicated the vessel’s active participation in narco-trafficking.
== Nature and significance == A quantity of radioactive waste typically consists of a number of radionuclides, which are unstable isotopes of elements that undergo decay and thereby emit ionizing radiation, which is harmful to humans and the environment. Different isotopes emit different types and levels of radiation, which last for different periods of time.
Sources: en.wikipedia.org
The peptide contains four residues in the order alanine, glutamate, aspartate and glycine, abbreviated AEDG. The chain is linear and held together by three peptide bonds. Its calculated mass for the uncharged free form is about 390.3 daltons.
Epithalamin refers to a crude preparation derived from bovine pineal tissue, which contains many components. Epitalon is a single synthetic tetrapeptide identified from that material and produced by chemical synthesis. The two names are sometimes confused because early reports treated the synthetic peptide as an active fragment of the extract.
It has been registered for clinical use in Russia, where it is associated with a small family of short peptides. In most other jurisdictions it is not an approved medicine and is traded as a research chemical. Regulatory status varies by country and changes over time.
Sealed lyophilised powder is normally kept at minus twenty degrees Celsius or below, away from light and moisture. Vials are allowed to reach room temperature before opening to limit condensation. Repeated warming and cooling of the same vial is discouraged.