A practical reference on Melanocortin receptor: what it is, how it behaves, what the literature reports, and where the honest uncertainties sit.
This page was last updated on 2025-12-17 and is reviewed periodically as new material appears.
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 binds to melanocortin receptors and is thought to influence neuronal survival and plasticity rather than to act through the adrenal axis. Laboratory work has shown increased expression of brain-derived neurotrophic factor and nerve growth factor in treated tissue. Changes in c-Fos, a marker of neuronal activation, have also been reported. Because the peptide is rapidly degraded by peptidases, its effects are generally attributed to downstream signaling cascades rather than to sustained receptor occupancy.
Published studies are dominated by animal models of stroke, ischemia, and cognitive impairment, with a smaller number of human trials conducted in Russia. Many of the human reports are small, single-center, and published in Russian-language journals, which limits independent scrutiny. Outcome measures vary between studies and often rely on clinician-rated scales rather than objective biomarkers. Systematic reviews have noted the methodological weaknesses and called for larger, preregistered trials before firm conclusions can be drawn.
| 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 |
Routine characterization relies on reversed-phase high-performance liquid chromatography to establish purity and on mass spectrometry to confirm molecular identity. Electrospray ionization and matrix-assisted laser desorption ionization are both used for mass verification. Amino acid analysis and peptide mapping can detect sequence errors. Common impurities include truncated sequences, methionine sulfoxide formed by oxidation, and deamidated products. Chromatograms are usually recorded near 214 nm, where the peptide backbone absorbs, and purity is reported as the percentage area of the principal peak.
Verification of a supplied batch generally combines a certificate of analysis with independent testing, because certificates are self-reported documents. A typical package includes a chromatographic trace, a mass spectrum, and a stated water or counter-ion content. Batch-to-batch consistency matters more than a single purity figure when results are compared across experiments. No single mandatory standard governs research-grade peptide release, so laboratories are expected to define their own acceptance criteria. Residual trifluoroacetate from purification is a frequently overlooked counter-ion.
Practical handling follows from those properties. Bulk material is best divided into single-use portions soon after receipt, because each thaw exposes the whole container to moisture and temperature cycling. Vials should be allowed to reach room temperature before opening to prevent condensation on the powder. Low-binding plasticware reduces loss of dilute solutions, and sterile filtration is used when a preparation must remain free of microbial growth. Records of batch number, reconstitution date and storage history are what allow a later analytical result to be interpreted meaningfully.
Identity and purity of Semax are established mainly by reversed-phase high-performance liquid chromatography coupled with mass spectrometry. The chromatographic trace gives a purity estimate as a percentage of total peak area, while electrospray or matrix-assisted laser desorption ionization confirms the molecular mass against the calculated value. Amino acid analysis and sequence-specific fragmentation provide further confirmation when a supplier's chain of custody is unclear. Vendors frequently quote a purity figure without stating the detection wavelength or the integration method, which limits how far one number can be compared with another.
Stability depends heavily on physical state. Lyophilized powder held dry, cold and dark retains its content over long periods, whereas dissolved peptide begins to change within days at room temperature. The most cited degradation route is oxidation of the methionine residue, which converts the peptide to a sulfoxide form that elutes differently on chromatography. Hydrolysis of amide bonds and adsorption onto container walls contribute smaller losses. Buffers that exclude oxygen from the headspace slow the oxidation pathway, but no single condition prevents all change indefinitely.
稳定性主要由水解与氧化两条路径支配。肽键在中性或弱酸性条件下相对稳定，遇到强碱或长时间高温则明显断裂；甲硫氨酸侧链容易被氧化成亚砜，使主峰前移并拉低实际含量。金属离子、光照和反复冻融会进一步促进降解或聚集。冻干粉在低温避光条件下可存放较长时间，配制后的水溶液通常需要冷藏并尽快用完。
纯度评估以反相高效液相色谱为主，通过主峰面积百分比给出粗略结果，再配合电喷雾质谱核对分子量。氨基酸分析可验证组成比例，手性色谱或毛细管电泳用于检查残基构型。常见杂质包括缺失序列的短肽、氧化产物与二聚体。由于多数市售品不附带完整检验报告，独立第三方检测常被用来核实标称值。
Several surgical procedures (sleep surgery) are used to treat sleep apnea, although they are normally a third line of treatment for those who reject or are not helped by CPAP treatment or dental appliances. Surgical treatment for obstructive sleep apnea needs to be individualized to address all anatomical areas of obstruction.
Proteoglycans are proteins that are heavily glycosylated. The basic proteoglycan unit consists of a "core protein" with one or more covalently attached glycosaminoglycan (GAG) chain(s). The point of attachment is a serine (Ser) residue to which the glycosaminoglycan is joined through a tetrasaccharide bridge (e.g. chondroitin sulfate-GlcA-Gal-Gal-Xyl-PROTEIN). The Ser residue is generally in the sequence -Ser-Gly-X-Gly- (where X can be any amino acid residue but proline), although not every protein with this sequence has an attached glycosaminoglycan. The chains are long, linear carbohydrate polymers that are negatively charged under physiological conditions due to the occurrence of sulfate and uronic acid groups. Proteoglycans occur in connective tissue.
CJC-1295 DAC, also known as DAC:GRF (short for drug affinity complex:growth hormone-releasing factor), is a synthetic analogue of growth hormone-releasing hormone (GHRH) (also known as growth hormone-releasing factor (GRF)) and a growth hormone secretagogue (GHS) which was developed by ConjuChem Biotechnologies. It is a modified form of GHRH (1-29) with improved pharmacokinetics, especially in regard to half-life.
Sources: en.wikipedia.org
===== Cuba ===== On 15 September, Lula and four of his cabinet minister visited Cuba where they met with Cuban president and first secretary of the Communist Party of Cuba Miguel Díaz-Canel. During his visit, Lula also attended a summit of the Group of 77 plus China in Havana where he lamented the United States embargo against Cuba stating that the island "is the victim of an illegal economic embargo, Brazil is against any unilateral coercive measure". Lula also criticized the inclusion of Cuba in the US list of states sponsors of terrorism.
=== Phase 1 === AZD-4041 – orexin OX1 receptor antagonist – opioid-related disorders BI-1356225 – ghrelin O-acyltransferase (GOAT) inhibitor – opioid-related disorders Cebranopadol (GRT-6005; PRK-101; TRN-228) – μ-opioid receptor agonist, nociceptin receptor agonist – substance-related disorders CSX-1004 – monoclonal antibody against fentanyl – opioid-related disorders Dimethyltryptamine/harmine (DMT/harmine; RE-01) – combination of dimethyltryptamine (DMT) (serotonin 5-HT2A receptor agonist and serotonergic psychedelic) and harmine (monoamine oxidase inhibitor (MAOI) and other actions) – cocaine-related disorders DPI-125 (MCP-201) – μ-opioid receptor agonist, δ-opioid receptor agonist, κ-opioid receptor agonist – opioid-related disorders Ibuprofen/ketotifen (SJP-005) – combination of ibuprofen (cyclooxygenase (COX) inhibitor/NSAID) and ketotifen (histamine H1 receptor antagonist, other actions) – opioid-related disorders Icalcaprant (ABBV-1354; CVL-354) – κ-opioid receptor antagonist – opioid-related disorders KNX-100 (SOC-1) – oxytocin-like drug / indirect oxytocin receptor modulator – opioid-related disorders, substance-related disorders Mavoglurant (AFQ-056; STP-7) – metabotropic glutamate mGlu5 receptor antagonist – cocaine-related disorders MEB-1170 – μ-opioid receptor biased agonist – opioid-related disorders Mebufotenin (5-MeO-DMT) – non-selective serotonin receptor agonist, serotonin 5-HT1A and 5-HT2A receptor agonist, and serotonergic psychedelic – substance use disorders MST-01 – undefined mechanism of action – smoking withdrawal Nalmefene (AV-104; TH-104) – μ-opioid receptor antagonist, κ-opioid receptor weak partial agonist – opioid-related disorders Naltrexone implantable pellets (BICX-102, BICX-104) – opioid receptor antagonist – alcoholism, opioid-related disorders, substance-related disorders Nezavist (DCUK-OEt) – peripherally selective GABAA receptor positive allosteric modulator (etomidate site) – alcoholism Noribogaine (DMX-1001) – various actions – alcoholism NRS-033 (nalmefene prodrug) – μ-opioid receptor antagonist, κ-opioid receptor weak partial agonist – opioid-related disorders OMS-527 (OMS-182399; OMS527) – phosphodiesterase PDE7 inhibitor – cocaine-related disorders Psilocybin (MLS-101/MLS101) – non-selective serotonin receptor agonist, serotonin 5-HT2A receptor agonist, serotonergic psychedelic – opioid-related disorders Smoking cessation therapeutics - Astraea Therapeutics – nicotinic acetylcholine receptor antagonists – smoking withdrawal SXC-2023 – cystine/glutamate transporter (SLC7A11) – cocaine-related disorders Tezampanel (LY-293558; NGX-424; PRN-001-01) – ionotropic glutamate AMPA and kainate receptor antagonist – opioid-related disorders Zabaglurant (Heptares 25; HTL-0014242; HTL14242; TMP-301) – metabotropic glutamate mGlu5 receptor negative allosteric modulator – cocaine-related disorders, substance-related disorders
== Overdose and toxicity == The German Federal Institute for Risk Assessment warns that muscimol and products containing it pose serious health risks, especially to children. The toxicity and safety profile of muscimol has been studied in various contexts, both experimental and clinical. It is described as being a relatively toxic compound in animals. The median lethal dose (LD50) in mice is 5.6 to 7 mg/kg intravenously, 3.8 mg/kg subcutaneously, 2.5 to 12 mg/kg intraperitoneally, and 22 mg orally. The LD50 in rats is 4.5 mg/kg intravenously and 45 mg/kg orally. Muscimol shows considerably greater lethal potency or toxicity than gaboxadol. A study on non-human primates indicated that muscimol, when administered in escalating doses, caused reversible hyperkinesia and dyskinesias at higher doses, but no long-term toxicity was observed on histological examination. Muscimol has shown potential as an anticonvulsant, blocking seizures induced by various agents in animal models without causing significant toxicity at therapeutic doses. Muscimol exhibits dose-dependent effects with higher doses leading to significant, but reversible, central nervous system symptoms. The dose of muscimol that is thought to be potentially fatal in humans has been reported to be approximately 90 mg, which is 15 times the reported threshold hallucinogenic dose of 6 mg.
=== 30 March === Wall Street Journal reporter Evan Gershkovich was arrested in Russia for spying by the Federal Security Service, near the Ural Mountains city of Yekaterinburg. He covered the invasion of Ukraine and the impact on Russian economy of international sanctions. In May, the FSB extended his pre-trial detention until 30 August.
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 associated with the melanocortin receptor family, particularly subtypes found in the central nervous system. This interaction is separate from the adrenal pathway activated by full-length ACTH.