Everything below concerns Epitalon. We keep the language plain, cite what the science says, and separate well-supported claims from open questions.
Last reviewed on 2025-08-29. Where a claim depends on a specific study, the study is described rather than over-claimed.
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.
Solubility is high in water, phosphate-buffered saline and normal saline, a pattern that follows from the two acidic residues in the chain. The peptide dissolves poorly in non-polar solvents such as hexane or chloroform. Stock solutions are often prepared in water first and then diluted into the buffer of interest. Because the molecule is small and hydrophilic, filtration through a low-protein-binding membrane is usually straightforward, and visible particulates are uncommon in freshly made solutions.
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.
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.
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.
| Property | Value | Notes |
|---|---|---|
| Appearance | White to off-white powder | Lyophilised and often hygroscopic |
| Solubility class | Freely soluble in water | Poor solubility in non-polar solvents |
| Typical storage temperature | -20 degrees Celsius or colder | Sealed, desiccated, protected from light |
| Typical analytical method | Reversed-phase HPLC with mass spectrometry | Establishes purity and confirms mass |
| Common salt form | Trifluoroacetate or acetate | Counterion reported alongside purity values |
Analytical characterization of epitalon relies on standard peptide methods. Reverse-phase high-performance liquid chromatography is used to assess purity, and mass spectrometry confirms identity by checking the observed mass against the expected value near 390 daltons. Amino acid analysis can verify composition. Because the peptide is short and hydrophilic, it elutes early on many reverse-phase columns, so method development often requires ion-pairing reagents to achieve adequate retention and resolution from related impurities.
Storage and handling follow conventional peptide practice. Lyophilized epitalon is typically kept refrigerated or frozen, protected from moisture and light, and allowed to equilibrate to room temperature before opening to avoid condensation. Once dissolved, aqueous solutions are usually stored cold and used within a short period, since dilute peptide solutions can support microbial growth and may slowly degrade. The absence of cysteine and methionine reduces, but does not eliminate, oxidation concerns during long-term storage.
Epitalon is a synthetic tetrapeptide with the sequence alanine-glutamate-aspartate-glycine, abbreviated AEDG. Its molecular formula is C14H22N4O9 and its calculated monoisotopic mass is approximately 390.35 daltons. The compound does not occur naturally as a free peptide; it is produced by solid-phase peptide synthesis. Because it contains two acidic residues and no basic residues, the neutral form carries a net negative charge at physiological pH. This charge profile influences how the peptide behaves in solution and during chromatographic analysis.
Laboratory-grade epitalon is typically supplied as a lyophilized powder. Purity is commonly assessed with reverse-phase high-performance liquid chromatography, often paired with mass spectrometry to confirm molecular identity. Amino acid analysis and peptide mapping can provide additional confirmation of sequence. Certificates of analysis for research materials frequently report purity above 95 percent, although the methods behind such figures vary between suppliers. The absence of a pharmacopeial monograph means that no single standardized assay defines the compound, so reported results depend on the analytical protocol chosen.
Storage recommendations center on limiting moisture, heat, and light. The dry powder is generally kept at minus 20 degrees Celsius, and some suppliers recommend minus 80 degrees for long-term archival. Once dissolved, solutions are usually aliquoted and frozen to avoid repeated freeze-thaw cycles, which can promote aggregation or degradation. Aqueous stability depends on pH and concentration, and buffered saline is often preferred over plain water for biological work. Stability data specific to epitalon remain limited, so general peptide-handling practices are applied by analogy rather than from product-specific validation.
=== Metabolism and excretion === Docetaxel is mainly metabolised in the liver by the cytochrome P450 CYP3A4 and CYP3A5 subfamilies of isoenzymes. Metabolism is principally oxidative and at the tert-butylpropionate side chain, resulting first in an alcohol docetaxel (M2), which is then cyclised to three further metabolites (M1, M3 and M4). M1 and M3 are two diastereomeric hydroxyoxazolidinones and M4 is an oxazolidinedione. Phase II trials of 577 patients showed docetaxel clearance is related to body surface area and to hepatic enzyme and alpha1 acid glycoprotein plasma levels. The following model represents docetaxel clearance in humans:
(1974), president of the University of the District of Columbia and former president of Southern University Reynold Verret (1976), president of Xavier University of Louisiana Gregory F. Ball (1977), psychologist, dean of the University of Maryland College of Behavioral and Social Sciences Thomas Worcester (1977), Jesuit academic, president of Regis College, Toronto, professor of the University of Toronto Alan Kadish (1977), president of the Touro College and University System Ralph Keen (1979), professor and dean of the honors college at the University of Illinois at Chicago Colin Crawford (1980), 24th dean of the University of Louisville School of Law and incoming dean of the Golden Gate University School of Law Samuel Hoi (1980), president of the Maryland Institute College of Art Daniel Gordis (1981), vice president of Shalem College, Israel's first liberal arts college Mark C. Gordon (1981), first president and dean of the Mitchell Hamline School of Law, former president of Defiance College and dean of the University of Detroit Mercy School of Law Donald S. Siegel (1981), economist and director of the School of Public Affairs at Arizona State University Deborah Waxman (1989), president of Reconstructionist Rabbinical College and Jewish Reconstructionist Communities Jonathan H.
== Laboratory performance == Newborn screening programs participate in quality control programs as in any other laboratory, with some notable exceptions. Much of the success of newborn screening programs is dependent on the filter paper used for the collection of the samples. Initial studies using Robert Guthrie's test for PKU reported high false positive rates that were attributed to a poorly selected type of filter paper. This source of variation has been eliminated in most newborn screening programs through standardization of approved sources of filter paper for use in newborn screening programs. In most regions, the newborn screening card (which contains demographic information as well as attached filter paper for blood collection) is supplied by the organization carrying out the testing, to remove variations from this source.
Sources: en.wikipedia.org
The United States was fighting not necessarily Soviet influence, but also any form of challenge to the American economic and political prerogatives through covert or military means. In this sense, the Cold War is less a story of rivalry between two blocs, but more a story of the ways by which the dominant states within each bloc controlled and disciplined their own populations and clients and about who supported and stood to benefit from increased arms production and political anxiety over a perceived external enemy.
== Kinetics == The rate at which organostannanes transmetalate with palladium catalysts is shown below. Sp2-hybridized carbon groups attached to tin are the most commonly used coupling partners, and sp3-hybridized carbons require harsher conditions and terminal alkynes may be coupled via a C-H bond through the Sonogashira reaction.
32S + n → 32P + p Neutron irradiation is performed in a nuclear reactor. The other main method used to synthesize radioisotopes is proton bombardment. The proton are accelerated to high energy either in a cyclotron or a linear accelerator.
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Sources: en.wikipedia.org
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.
Reversed-phase HPLC establishes purity and separation from related peptides, and mass spectrometry confirms the molecular mass. Amino acid analysis can verify residue composition. No single method proves identity on its own, so the results are read together.
Yes. Residual trifluoroacetate or acetate from purification adds mass and can shift the value obtained by certain assays. Purity figures are therefore meaningful only when the counterion form is stated. Reporting both peptide content and salt form gives a clearer picture.
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.