lyophilized powder 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.
Last reviewed on 2026-01-16. Where a claim depends on a specific study, the study is described rather than over-claimed.
Semax is normally supplied as a lyophilized powder, and that form is the most stable. Suppliers commonly recommend storage at -20 °C in a desiccated container protected from light, with short-term handling at room temperature limited to weighing and transfer. Powder that has absorbed moisture degrades faster, so vials should be warmed to ambient temperature before opening to prevent condensation on the contents. Hygroscopic behavior is typical of short hydrophilic peptides, and humidity control matters more than temperature alone for long-term retention.
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.
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.
| Property | Value | Notes |
|---|---|---|
| Solid storage temperature | -20 °C or below | Desiccated and protected from light |
| Solution storage temperature | -80 °C as single-use aliquots | Avoid repeated freeze-thaw cycles |
| Purity assessment method | RP-HPLC, around 214 nm | Reported as main-peak area percent |
| Identity confirmation method | ESI-MS or MALDI-TOF | Measured mass compared with calculated mass |
| Common synonyms | ACTH(4-10) analog; Met-Glu-His-Phe-Pro-Gly-Pro | Also written as Semaxum in some sources |
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.
Published research has focused mainly on neurological and cognitive endpoints in animal models, with proposed mechanisms involving brain-derived neurotrophic factor and related signalling pathways. A substantial share of the human data originates from a limited number of research groups, and independent replication in other countries remains sparse. Regulatory status reflects that distribution: the peptide is registered as a medicine in Russia and appears in some neighbouring markets, while elsewhere it is handled as a research chemical without approved therapeutic labelling. Questions about dose-response relationships, long-term effects, and comparability across studies are still open.
Semax is a synthetic heptapeptide with the sequence Met-Glu-His-Phe-Pro-Gly-Pro. It is described in the literature as an analogue of the ACTH(4–10) fragment, a short N-terminal portion of adrenocorticotropic hormone that retains some neurotropic activity without the full hormonal effects of the parent peptide. The molecule carries a methionine residue at the N-terminus and two proline residues near the C-terminus, features that shape both its interactions with receptor systems and its chemical stability. The free peptide corresponds to the formula C37H51N9O10S and a molecular mass near 813.9 Da.
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.
. The superscript "+" indicates the ion charge and the superscript "•" indicates an unpaired electron of the radical ion. The energy of the electron beam is typically 70 electronvolts and the ionization process typically produces extensive fragmentation of the chemical bonds of the molecule. Due to the high vacuum pressure in the ionization chamber, the mean free path of molecules are varying from 10 cm to 1 km and then the fragmentations are unimolecular processes. Once the fragmentation is initiated, the electron is first excited from the site with the lowest ionization energy. Since the order of the electron energy is non-bonding electrons > pi bond electrons > sigma bond electrons, the order of ionization preference is non-bonding electrons > pi bond electrons > sigma bond electrons.
The Cold War had provided external stabilizing pressures. Both the United States and the Soviet Union had a vested interest in Yugoslavia's stability, ensuring it remained a buffer state in the east–west divide. This resulted in financial and political support for its regime. When the Cold War ended, this external support evaporated, leaving Yugoslavia more vulnerable to internal divisions. As Yugoslavia fragmented, the wars began after Slovenia and Croatia declared independence in 1991. Serbia, under Slobodan Milošević, opposed these moves. The Bosnian War (1992–1995) was the most brutal of the Yugoslav Wars, characterized by ethnic cleansing and genocide. International organizations, including the United Nations, struggled to manage the violence. NATO eventually intervened with airstrikes in Bosnia (1995) as part of Operation Deliberate Force and later in Kosovo (1999) as part of Operation Allied Force. These interventions marked the transition of NATO as a deterrent to the Soviet Union, to also functioning at the time as an active peacekeeping and conflict-resolution force.
=== October === October 10, 2008: Singapore First Asian country to slip into a recession since the credit crisis began. Singapore's export-dependent economy shrank an annualized 6.3% in the third quarter after a revised 5.7% contraction in the second quarter; its first recession since 2002. Growth has faltered in Singapore as a result of less demand for exports, a reduction in tourism, and the end of the real-estate boom. Singapore's manufacturing sector had declined 4.9% in the previous quarter.
Sources: en.wikipedia.org
A surface is prepared with a known quantity of capture antibody. Any nonspecific binding sites on the surface are blocked. The antigen-containing sample is applied to the plate, and captured by antibody. The plate is washed to remove unbound antigen. A specific antibody is added, and binds to antigen (hence the 'sandwich': the antigen is stuck between two antibodies). This primary antibody could be in the serum of a donor, to be tested for reactivity towards the antigen. Enzyme-linked secondary antibodies are applied as detection antibodies, which bind specifically to the antibody's Fc region (nonspecific). The plate is washed to remove the unbound antibody-enzyme conjugates. A chemical is added to be converted by the enzyme into a color, fluorescent, or electrochemical signal. The absorbance, fluorescence, or electrochemical signal (e.g., current) of the plate's wells is measured to determine the presence and quantity of the antigen. The image to the right includes the use of a secondary antibody conjugated to an enzyme, although, in the technical sense, this is not necessary if the primary antibody is conjugated to an enzyme (which would be direct ELISA). However, the use of a secondary-antibody conjugate avoids the expensive process of creating enzyme-linked antibodies for every antigen one might want to detect. By using an enzyme-linked antibody that binds the Fc region of other antibodies, this same enzyme-linked antibody can be used in a variety of situations.
=== Field management === As mentioned, permissive hypotension (restrictive fluid therapy) is unwise. Careful fluid overload and administration of intravenous sodium bicarbonate is wise, especially if the crushing weight is on the patient for more than four hours, but often if it persists more than one hour. The San Francisco emergency services protocol calls for a basic adult dose of a 2 L bolus of normal saline followed by 500 mL/h, limited for "pediatric patients and patients with history of cardiac or renal dysfunction". Use of a tourniquet can stall the life-threatening consequences of a crush related injury and can be a second option if the person cannot immediately have the fluids that were lost be medically replaced back into the body. Tourniquet measures should be taken if the person has been trapped for more than two hours.
=== Brett Hazard: A Bully finds Religion === Meet Brett Hazard, a loud mouthed bully who picks on Zack because of his religion and even nominated him for Prom Queen. This episode did not air on American TV during the season's initial run on MTV but eventually aired on MTV2 on October 4, 2012. However, it has aired on the Fox8 channel of Foxtel and Austar in Australia. This episode is not available on the Bully Beatdown website or iTunes, and has not been leaked to the internet. A few clips of it can be seen at the end of the previous episode (Jordan: Bring Out The Boar). At the end of that episode, a preview for this episode was shown.
The pia mater (Latin: tender mother) is a very delicate membrane. It is the meningeal envelope that firmly adheres to the surfaces of the brain and spinal cord, following all of the brain's contours (gyri and sulci). It is a very thin sheet of connective tissue that interfaces with the glial limitans superficialis but lacks capillaries itself.
Sources: en.wikipedia.org
== History == Pacinian corpuscles were the first cellular sensory receptor ever observed. They were first reported by German anatomist and botanist Abraham Vater and his student Johannes Gottlieb Lehmann in 1741, but ultimately named after Italian anatomist Filippo Pacini, who rediscovered them in 1835. John Shekleton, a curator of the Royal College of Surgeons in Ireland, also discovered them before Pacini, but his results were published later. Similar to Pacinian corpuscles, Herbst corpuscles and Grandry corpuscles are found in bird species.
== History == The sinoatrial node was first discovered by a young medical student, Martin Flack, in the heart of a mole, whilst his mentor, Sir Arthur Keith, was on a bicycle ride with his wife. They made the discovery in a makeshift laboratory set up in a farmhouse in Kent, England, called Mann's Place. Their discovery was published in 1907.
==== Other methods of hydrogen storage ==== There are six possible methods that can be used for the reversible storage of hydrogen with a high volumetric and gravimetric density, which are summarized in the following table, (where ρm is the gravimetric density, ρv is the volumetric density, T is the working temperature, and P is the working pressure):
ATP + NH3 + CO2 ⇌ ADP + H2N−C(=O)−O−PO2−3 An important example of an enzyme with this activity is carbamoyl phosphate synthetase, e.g. carbamoyl phosphate synthetase I carrying out the first step of the urea cycle in order to dispose of waste ammonia. One hemoglobin molecule can carry four molecules of carbon dioxide to the lungs as carbamate groups formed by reaction of CO2 with four terminal amine groups of the deoxy form. The resulting compound is called carbaminohaemoglobin.
2 H2O + 2 A + (light, chloroplasts) → 2 AH2 + O2 A is the electron acceptor. Therefore, in light, the electron acceptor is reduced and oxygen is evolved. Samuel Ruben and Martin Kamen used radioactive isotopes to determine that the oxygen liberated in photosynthesis came from the water.
Sources: en.wikipedia.org
Each freeze-thaw cycle can degrade a fraction of the peptide and promote aggregation. Dividing a stock solution into single-use volumes removes repeated cycling as a variable. It also limits the time a thawed solution spends at room temperature.
A high main-peak percentage says little about identity, counter-ion content, or residual solvents. It also does not distinguish an isomer or a closely eluting analog. Mass confirmation and the accompanying documentation cover those gaps.
Salt form changes mass, solubility, and hygroscopicity, and acetate and trifluoroacetate salts behave differently in solution. Storage guidance still centers on -20 °C for powder and lower temperatures for solutions. The certificate should state which salt is present.
It is a synthetic seven-amino-acid peptide built from the ACTH(4-7) sequence plus a Pro-Gly-Pro tail. It belongs to the family of short ACTH fragments studied for nervous-system effects. Its backbone contains only standard amino acids.