shelf life is one of those subjects where the details matter more than the headlines. This page pulls together the background, the mechanisms, and the practical points readers ask about most.
Updated 2026-04-07. Numbers and descriptions here follow the published literature rather than marketing material.
Purity assessment relies mainly on reversed-phase high-performance liquid chromatography, which separates the target heptapeptide from truncated sequences, deletion analogues, and oxidised forms. Mass spectrometry, usually coupled to liquid chromatography, confirms identity through the expected molecular ion and reveals modifications such as methionine sulfoxide formation. Amino acid analysis can verify composition, and tandem mass spectrometry supports sequence confirmation. Ultraviolet detection near 254 to 280 nanometres is convenient because the phenylalanine and histidine residues absorb in that region. Nuclear magnetic resonance is rarely used for routine release testing.
Common degradation pathways include oxidation of the methionine side chain, hydrolysis of the peptide backbone, and aggregation under unfavourable pH or concentration. Stability studies typically monitor the main peak by chromatography and report total related substances as a percentage. Because no official monograph exists, acceptance criteria vary between laboratories, and reported purity values are not directly comparable across suppliers. Analysts therefore document the method, column, and detection wavelength alongside each result, and open questions remain about how much biological activity the oxidised forms retain.
The compound was developed in the 1980s at the Institute of Molecular Genetics in Moscow, where it emerged from research on short ACTH fragments and their effects on the central nervous system. Russian pharmaceutical listings describe it as a nootropic and neuroprotective agent, most often formulated as nasal drops. It is not a marketed medicine in the United States or the European Union, and no pharmacopoeial monograph covers it. Consequently, most published clinical experience with the substance originates from a small number of research centres, mainly in Russia and neighbouring countries.
Pharmacological accounts link semax to melanocortin signalling and to modulation of neurotrophic factor expression, particularly brain-derived neurotrophic factor and nerve growth factor. Much of this evidence comes from rodent studies using intranasal delivery, a route chosen because it allows peptides to reach the central nervous system with limited systemic exposure. Whether the same mechanisms operate in humans at comparable magnitude remains an open question. The precise receptor or receptors responsible for the reported behavioural and neuroprotective effects have not been conclusively identified.
| Property | Value | Notes |
|---|---|---|
| Typical analytical method | Reversed-phase HPLC with UV detection | Separates target peptide from truncated and oxidised forms |
| Identity confirmation | LC-MS or ESI-MS | Compares observed and calculated molecular ion |
| Primary degradation route | Methionine oxidation | Forms the sulfoxide; monitored as an early-eluting peak |
| Short-term storage | 2 to 8 degrees Celsius | Applies to working vials and reconstituted portions |
| Common synonyms | ACTH(4–10) analogue, MEHFPGP | Descriptive names used in laboratory catalogues |
Lyophilised powder is normally kept at -20 °C in a desiccated container, with some suppliers recommending -80 °C for long-term archival storage. Repeated freeze-thaw cycles are the most common cause of avoidable loss, so aliquoting before freezing reduces variability between working sessions. Dissolved peptide is far less stable than the dry solid and is usually prepared fresh or held briefly at 4 °C. Aqueous solutions support both hydrolysis of the backbone and oxidation of the N-terminal methionine, and these two routes dominate degradation under ordinary laboratory conditions.
Identity and purity are confirmed with reversed-phase high-performance liquid chromatography, typically monitored at 214 nanometres where the peptide bond absorbs. Mass spectrometry, either electrospray or MALDI-TOF, verifies molecular mass against the theoretical value and detects truncation or adduct formation. Amino acid analysis and peptide mapping provide additional confirmation when required. The most frequently reported impurities are deletion sequences from incomplete coupling, methionine sulfoxide from oxidation, and dimeric species formed through non-covalent aggregation. Impurity profiles depend strongly on the synthesis and purification route chosen by the producer.
Semax is a synthetic heptapeptide with the sequence Met-Glu-His-Phe-Pro-Gly-Pro. Its design combines the ACTH(4-7) core fragment with a C-terminal Pro-Gly-Pro extension, a modification intended to improve stability and prolong activity. The molecule is hydrophilic, carries no lipid chains or glycosylation, and has a theoretical mass just over 810 daltons in its free form. All seven residues are proteinogenic amino acids, so no non-natural building blocks appear in the backbone. A free N-terminal methionine and C-terminal proline define the unmodified parent peptide.
The compound was developed during the 1980s at the Institute of Molecular Genetics in Moscow as part of research on fragments of adrenocorticotropic hormone. Early work examined short ACTH-derived sequences that retained neurotrophic effects while lacking the endocrine activity of the full hormone. Semax entered clinical use in Russia during the 1990s, where it received registration for several neurological indications. Outside that region it remained primarily a laboratory research material rather than an approved therapeutic. English-language literature on it grew more slowly and frequently cited the original Russian studies.
Terminology around the compound varies by source. It appears in catalogues and papers as Semax, as the heptapeptide ACTH(4-7)-Pro-Gly-Pro, and under various alphanumeric laboratory codes used by individual suppliers. These names refer to the same sequence but may imply different salt forms, purity grades, or counter-ions. Peptide databases usually list the free base mass, while product descriptions sometimes report acetate or trifluoroacetate salts with a different formula weight. Because naming conventions for research peptides are not standardised across vendors, checking the declared sequence and measured mass is more reliable than relying on a trade name alone.
Once dissolved, the peptide is considerably less stable than the solid. Aqueous solutions are usually prepared at neutral to slightly acidic pH, filtered, and divided into single-use aliquots before freezing. Repeated freeze-thaw cycles are a common cause of avoidable loss and are best prevented by never refreezing a thawed aliquot. Adsorption to plastic and glass surfaces can lower the measured concentration of dilute solutions, particularly below roughly 0.1 mg/mL. Buffer choice, salt content, and container material all influence how much peptide remains detectable after storage.
Identity and purity are established with standard peptide methods. Reversed-phase HPLC with ultraviolet detection near 214 nm resolves the parent peak from deletion and truncation byproducts, and reports typically quote a main-peak percentage. Mass spectrometry by electrospray or MALDI-TOF confirms the expected molecular mass, while amino acid analysis or peptide mapping can verify composition when the sequence itself is in question. A certificate of analysis that pairs a chromatogram with a mass spectrum is more informative than a purity figure alone. Counter-ion content and residual solvents are separate specifications and are frequently omitted.
Reported pharmacological work centers on neurotrophic signaling, including changes in BDNF and NGF expression in hippocampal tissue in animal models. Human data come largely from studies conducted in Russia, and how well those results generalize to other populations remains an open question. Regulatory status differs sharply by jurisdiction: Semax is a registered prescription medicine in Russia, while it holds no approved marketing status in the United States or the European Union. Outside such jurisdictions it is generally handled as a research chemical, which affects both documentation and quality expectations.
Semax is a synthetic heptapeptide whose sequence is Met-Glu-His-Phe-Pro-Gly-Pro. It was developed as a fragment analog of adrenocorticotropic hormone, modeled specifically on the ACTH(4-10) region. The first four residues reproduce that fragment, while a Pro-Gly-Pro tripeptide is appended at the C-terminus. Work on the compound originated in Russia, where it entered clinical use as an intranasal preparation. Its sequence places it among short regulatory peptides studied for effects on the central nervous system rather than on the adrenal axis.
The C-terminal Pro-Gly-Pro extension is not incidental. Proline-rich tails are known to resist several common peptidases, and the published literature attributes the longer half-life of Semax, relative to unmodified ACTH fragments, to this feature. The modification also removes the melanocyte-stimulating and corticosteroidogenic activity that characterizes longer ACTH-derived sequences. Because the molecule is small and hydrophilic, it is typically formulated as an aqueous solution for intranasal or parenteral delivery. Acetylation or amidation at the termini appears in closely related research peptides and shifts the mass by a fixed increment.
== Public image == Kallingal's roles in 22 Female Kottayam, August Club, and Rani Padmini are cited among the strongest female-led characters in Malayalam cinema. Kallingal was named the Kochi Times Most Desirable Woman in 2012.
=== Farnesoid X-receptor agonist === A new novel treatment option is the farnesoid X receptor is responsible for regulating bile acid homeostasis. An agonist of this nuclear hormone receptor is seen as a possible treatment as it can downregulate bile acid synthesis and reabsorption. Further the farnesoid X receptor is partly responsible for lipid and glucose homeostasis, as well as pathogen recognition. An agonist for the farnesoid X receptor can therefore lead to an anti-cholestatic environment to minimize the effect of toxic bile acids on the liver. A candidate agonist for the farnesoid X receptor is obeticholic acid with experiments showing it has very strong affinity. A worry though is despite benefits in the biochemical pathways, pruritus was more intense and prevalent than the placebo. A titration strategy may help to mitigate pruritus, but FDA approval for obeticholic acid is currently unlikely. In fact, in February 2018, the FDA gave a black box warning for OCA. A recent study did find that if the drug is given with UDCA, the incidence for cirrhosis and liver transplants decreases. Another target that is being looked into is the all-trans retinoic acid (ATRA), an activator for the retinoid X receptor. In vitro and animal studies found ATRA had lowered the amount of bile acid and decreased hepatic inflammation.
== Etymology == Moscow's name is thought to be derived from that of the Moskva River. Multiple theories have been proposed for the origin of this river's name. The linguistically best-grounded and most widely accepted theory is that the name comes from the Proto-Balto-Slavic root *mŭzg-/muzg-, from the Proto-Indo-European *meu- "wet"; thus, the name Moskva might signify a river at a wetland or marsh. The name's cognates include the following:
Alkali metal cations do not usually form coordination complexes with simple Lewis bases due to their low charge of just +1 and their relatively large size; thus the Li+ ion forms most complexes and the heavier alkali metal ions form less and less (though exceptions occur for weak complexes). Lithium in particular has a very rich coordination chemistry in which it exhibits coordination numbers from 1 to 12, although octahedral hexacoordination is its preferred mode. In aqueous solution, the alkali metal ions exist as octahedral hexahydrate complexes [M(H2O)6]+, with the exception of the lithium ion, which due to its small size forms tetrahedral tetrahydrate complexes [Li(H2O)4]+; the alkali metals form these complexes because their ions are attracted by electrostatic forces of attraction to the polar water molecules. Because of this, anhydrous salts containing alkali metal cations are often used as desiccants. Alkali metals also readily form complexes with crown ethers (e.g. 12-crown-4 for Li+, 15-crown-5 for Na+, 18-crown-6 for K+, and 21-crown-7 for Rb+) and cryptands due to electrostatic attraction.
Sources: en.wikipedia.org
Progestogens, also sometimes written progestins, progestagens or gestagens, are a class of natural or synthetic steroid hormones that bind to and activate the progesterone receptors (PR). Progesterone is the major and most important progestogen in the body. The progestogens are named for their function in maintaining pregnancy (i.e., progestational), although they are also present at other phases of the estrous and menstrual cycles. The progestogens are one of three types of sex hormones, the others being estrogens like estradiol and androgens/anabolic steroids like testosterone. In addition, they are one of the five major classes of steroid hormones, the others being the androgens, estrogens, glucocorticoids, and mineralocorticoids, as well as the neurosteroids. All endogenous progestogens are characterized by their basic 21-carbon skeleton, called a pregnane skeleton (C21). In similar manner, the estrogens possess an estrane skeleton (C18), and androgens, an androstane skeleton (C19). The terms progesterone, progestogen, and progestin are mistakenly used interchangeably both in the scientific literature and in clinical settings. Progestins are synthetic progestogens and are used in medicine. Major examples of progestins include the 17α-hydroxyprogesterone derivative medroxyprogesterone acetate and the 19-nortestosterone derivative norethisterone. The progestins are structural analogues of progesterone and have progestogenic activity similarly, but differ from progesterone in their pharmacological properties in various ways.
On March 23 2023, Brazilian police raided the Salgueiro favela in São Gonçalo, Rio de Janeiro, killing Leonardo Costa Araujo, the head of CV in Para, and other 12 gangsters. On September 4 2025, eight members of the Terceiro Comando Puro were killed in a shootout with police in Rio de Janeiro. Later, on October 28, 2025, against the backdrop of COP30, Brazilian police launched Operation Containment on Comando Vermelho spots in Rio de Janeiro, arresting at least 81 suspected gang members while resulting in the deaths of more than 132 people, including four police officers and at least 17 residents without prior criminal records. On 14 January 2026, four people were killed in a police operation against the Comando Vermelho in the Salgueiro favela of Rio de Janeiro. On 18 March, eight people, including Comando Vermelho commander Claudio Augusto dos Santos, were killed in police raids across Rio de Janeiro.
A review of different cell geometries with their specific electric configurations is available in the literature. However, ICR cells can belong to one of the following two categories: closed cells or open cells. Several closed ICR cells with different geometries were fabricated and their performance has been characterized. Grids were used as end caps to apply an axial electric field for trapping ions axially (parallel to the magnetic field lines). Ions can be either generated inside the cell or can be injected to the cell from an external ionization source. Nested ICR cells with double pair of grids were also fabricated to trap both positive and negative ions simultaneously. The most common open cell geometry is a cylinder, which is axially segmented to produce electrodes in the shape of a ring. The central ring electrode is commonly used for applying radial excitation electric field and detection. DC electric voltage is applied on the terminal ring electrodes to trap ions along the magnetic field lines. Open cylindrical cells with ring electrodes of different diameters have also been designed. They proved not only capable in trapping and detecting both ion polarities simultaneously, but also they succeeded to separate positive from negative ions radially. This presented a large discrimination in kinetic ion acceleration between positive and negative ions trapped simultaneously inside the new cell. Several ion axial acceleration schemes were recently written for ion–ion collision studies.
Sources: en.wikipedia.org
In 1910, when Loeb moved to The Rockefeller Institute for Medical Research in New York, Robertson was promoted to Associate Professor of Physiological Chemistry within the School of Medicine; and, in 1916, he was appointed as full Professor of Biochemistry in the new, separate, Department of Biochemistry and Pharmacology that had just been established in the university's School of Medicine. By this time, through his "investigat[ions of the] diverse aspects of mechanisms of growth and longevity in plants, animals and humans", Robertson had already "gained international repute as a leader in the field of biochemistry".
Former interim leader of the party and MLA for Surrey-White Rock Trevor Halford, former leader and MLA for Nechako Lakes John Rustad, and MLA for Skeena Claire Rattée were all removed. Rattée issued a statement claiming Findlay was “attempting to oust members of her own caucus, demonstrating poor judgement that doesn’t befit someone who is attempting to become premier.” Since July 2026, multiple staffers have also resigned from the party, including former executive director Angelo Isidorou, former party president Aisha Estey and former vice-president Sharon White. These positions have been replaced by many controversial figures, including Apollo Chung, a former member of the separatist Republican Party of Alberta, and Chris Delaney, notable for his ties to former British Columbia Premier Bill Vander Zalm. In September 2026, allegations emerged that Findlay had hired a private investigator to watch Conservative critics, including sitting Conservative MLAs and a journalist. Findlay claims she was "unaware." MLA for Skeena Claire Rattée, who identified herself as one of the targets, said at least 10 members of caucus have signed a letter asking Findlay to resign. Rattée was later removed from caucus by Findlay. Former Conservative MLA Brennan Day, and former party executive director Angelou Isidorou also identified themselves as alleged targets. On September 20, 2026, Findlay announced her resignation as leader of the Conservative Party of BC.
=== Toxins === P. aeruginosa uses the virulence factor exotoxin A to inactivate eukaryotic elongation factor 2 via ADP-ribosylation in the host cell, much as the diphtheria toxin does. Without elongation factor 2, eukaryotic cells cannot synthesize proteins and necrotise. The release of intracellular contents induces an immunologic response in immunocompetent patients. In addition P. aeruginosa uses an exoenzyme, ExoU, which degrades the plasma membrane of eukaryotic cells, leading to lysis. Increasingly, it is becoming recognized that the iron-acquiring siderophore, pyoverdine, also functions as a toxin by removing iron from mitochondria, inflicting damage on this organelle. Since pyoverdine is secreted into the environment, it can be easily detected by the host or predator, resulting the host/predator migration towards the bacteria.
Sources: en.wikipedia.org
Dry powder is usually kept at about -20 degrees Celsius for long-term storage and at 2 to 8 degrees Celsius for short working periods. Containers should stay sealed and protected from light and moisture to limit degradation.
Oxidation of the methionine residue to the sulfoxide is a frequently reported change, and it usually appears as an earlier-eluting peak in reversed-phase chromatography. Backbone hydrolysis products can also accumulate in aqueous solution.
Liquid chromatography coupled with mass spectrometry is the usual approach, because the observed molecular ion can be compared with a calculated mass of about 813.9 Da. Retention time alone does not establish identity.
It is described as a synthetic analogue of the ACTH(4–10) fragment, a short segment of adrenocorticotropic hormone. Its sequence differs from that fragment and includes two proline residues, which influence stability and behaviour in solution.