This is a working overview of methionine sulfoxide, written for readers who want more than a one-paragraph summary but less than a textbook.
This page was last updated on 2026-07-03 and is reviewed periodically as new material appears.
Regulatory status differs sharply between jurisdictions. In Russia the peptide is registered as a prescription nasal preparation, while agencies such as the United States Food and Drug Administration have not approved it for any indication. Products sold elsewhere are typically labeled for laboratory research only, and such labels shift responsibility for safe handling to the purchaser. Because the same name covers pharmaceutical-grade nasal drops and bulk research powder, identity and purity documentation becomes the main practical concern when comparing sources.
Semax is a synthetic seven-amino-acid peptide whose sequence extends the ACTH(4-10) fragment with a C-terminal proline-glycine-proline tripeptide. The commonly cited sequence is Met-Glu-His-Phe-Pro-Gly-Pro, giving a molecular formula near C37H51N9O10S and a molecular weight close to 813.9 g/mol. It belongs to the broader class of synthetic ACTH fragments studied for central nervous system effects rather than for adrenal steroid stimulation. In practice the material appears as a lyophilized white powder for laboratory work or as a dilute saline solution in clinical settings.
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.
Solid semax is typically supplied as a lyophilised powder that is hygroscopic and sensitive to moisture, light, and repeated temperature cycling. Long-term storage of the dry peptide is generally recommended at approximately -20 degrees Celsius, while shorter working periods may use refrigeration at 2 to 8 degrees Celsius. Vials should remain tightly closed and desiccated when brought to room temperature, because condensation can damage the material before it is weighed. Dividing a batch into aliquots is preferable to thawing one container repeatedly.
| Property | Value | Notes |
|---|---|---|
| Chemical class | Synthetic heptapeptide (ACTH fragment analog) | Not a steroid; does not belong to the melanocortin agonist drugs by marketing category |
| Molecular formula | C37H51N9O10S (commonly cited) | Reported values vary slightly with salt and counter-ion content |
| Appearance | White to off-white lyophilized powder | A single batch may appear as a loose cake or fluffy solid |
| Solubility | Freely soluble in water and aqueous buffer | Stock solutions are usually prepared in sterile water or saline |
| Typical storage | −20 °C or below, desiccated and protected from light | Seal opened vials promptly to limit moisture uptake |
当时的短肽研究普遍关注能否穿越血脑屏障、在低剂量下产生中枢效应，Semax 属于这一路线。鼻内给药是其主要使用方式，俄语文献报道的适应症涵盖缺血性卒中、短暂性脑缺血发作、认知功能减退以及视神经病变。这些研究大多发表在当地期刊上，样本规模与终点设置同西方试验惯例存在差异，国际同行对其临床证据的强度看法不一。
各国监管态度分化明显。俄罗斯按处方药管理，部分东欧国家留有使用记录；欧盟与美国未批准其作为药物上市，市面流通品通常标注为研究用化学品。身份差异意味着标示含量、纯度与无菌性缺少统一核查。体育领域还牵涉反兴奋剂名录，跨境携带则受目的地药品法规约束。
Semax 是人工设计的七肽，序列为 Met-Glu-His-Phe-Pro-Gly-Pro，骨架取自促肾上腺皮质激素片段 ACTH(4-10)。它于二十世纪八十年代在苏联的分子遗传学研究机构内合成。设计目标是保留该片段与注意力和记忆相关的活性，同时剔除促皮质激素释放等内分泌作用。此后俄罗斯将其登记为药品并进入临床使用。
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. It corresponds to the ACTH(4-7) fragment extended at the C-terminus by a Pro-Gly-Pro tripeptide, an addition intended to slow enzymatic breakdown. The molecular formula is C37H51N9O10S and the molecular mass is approximately 814 daltons. In the literature it is often described as an ACTH(4-10) analog, although that label reflects a naming convention as much as a precise structural relationship. The compound was developed in Russia and remains most closely associated with that research tradition.
Laboratory descriptions of the material are consistent across suppliers. It appears as a white to off-white lyophilized powder that dissolves readily in water and in polar organic solvents such as dimethyl sulfoxide. Aqueous solutions are clear and colorless at low concentrations. Because the peptide contains methionine, oxidation at the sulfur atom is a recognized degradation pathway, and handling notes usually call for protected, desiccated storage. Reported purity for research-grade lots is generally above 95 percent as measured by reversed-phase high-performance liquid chromatography.
The compound is registered in Russia as a pharmaceutical product, most commonly formulated as a nasal solution, and has been used in that setting since the 1990s. Outside that jurisdiction it is generally handled as a research chemical rather than an approved medicine. Regulatory status therefore differs sharply between countries, and material sold internationally may not correspond to the Russian pharmaceutical formulation. Documentation with commercial samples is typically limited to a certificate of analysis covering purity and identity, not clinical status or local legal classification.
(S)-corytuberine synthase is an enzyme purified from the plant Coptis japonica (Japanese goldthread), with EC number EC 1.14.19.51 and CYP Symbol CYP80G2. It catalyses an intramolecular C-C phenol coupling of (S)-reticuline to (S)-corytuberine in a pathway leading to magnoflorine.
As recently as 1967, the World Health Organization estimated that 15 million people contracted the disease and that two million died in that year. After successful vaccination campaigns throughout the 19th and 20th centuries, the WHO certified the global eradication of smallpox in May 1980. Smallpox is one of two infectious diseases to have been eradicated, the other being rinderpest, which was declared eradicated in 2011. The final known fatal case occurred in 1978 in a laboratory in Birmingham, England.
In December 2016, Chipotle announced that co-CEO Monty Moran had stepped down from his role effective immediately with Ells becoming the sole CEO. Eleven months later, Ells announced in November 2017 that he would be stepping down as CEO. In December 2017, Chipotle announced it signed a 15-year lease and in late 2018 will move around 450 corporate employees—currently housed in multiple buildings around downtown Denver—into the new 1144 Fifteenth Tower and occupy around 126,000 square feet, or 5 floors, of the 40-story tower. In February 2018, Chipotle announced that Taco Bell CEO Brian Niccol would replace Ells as CEO starting on March 5 while Ells would retain his chairman position. Many industry analysts praised Niccol's appointment saying that Chipotle "needed new blood". Chipotle stock went up $30.27, or 12.04%, as a result of the announcement. However, other analysts criticized the announcement by saying that "the move goes against everything the burrito chain stands for". In May 2018, Chipotle announced that it would relocate its headquarters from Denver to Newport Beach, California. Corporate functions handled in their Denver and New York offices would move to Newport Beach or to an existing office in Columbus, Ohio. This move would impact 400 workers, some being offered relocation and retention packages. In May 2018, Chipotle announced the "Chipotlane" and began testing it in the U.S.
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Sources: en.wikipedia.org
. in a linear manner. Thus, quinoline-based indicators are one-wavelength dyes - the signal results from monitoring the fluorescence at a single wavelength. Ratiometric measurement of halide concentration is not possible with quinolinium dyes. The kinetics of collision quenching are diffusion-limited only, and these indicators provide submillisecond time resolution. Quinolinium-based dyes are insensitive to physiological changes in pH, but they are prone to strong bleaching and demand ultraviolet excitation, which is harmful for living organisms. Because quinolinium is not occurring in the cells naturally, cell loading is necessary. However, quinolinium-based dyes aren't retained perfectly in the cell and can't be targeted easily to subcellular organelles. Also, they cannot be designed specific to a certain type of cell. The most used quinolinium-based Cl− indicators are 6-methoxy-1-(3-sulfonatopropyl) quinolinium (SPQ), 6-methoxy-N-ethylquinolium Cl− (MEQ), and N-(6-methoxyquinolyl)-acetoethyl ester (MQAE).
=== End-of-life care === In the final stages of end-of-life care, midazolam is routinely used at low doses via subcutaneous injection to help with agitation, restlessness, or anxiety in the last hours or days of life. Midazolam is considered a first-line agent in palliative continuous deep sedation therapy—when it is necessary to alleviate intolerable suffering not responsive to other treatments, but the need for higher doses is rare.
Ipragliflozin (INN, trade names Suglat) is a pharmaceutical drug for treatment of type 2 diabetes. Ipragliflozin, jointly developed by Astellas Pharma and Kotobuki Pharmaceutical, was approved in Japan on January 17, 2014, and in Russia on May 22, 2019. Ipragliflozin is a Sodium/glucose cotransporter 2 (SGLT2) inhibitor (gliflozin). These membrane proteins are on the cell surface and transfer glucose into the cells. SGLT2 is one subtype of SGLTs and plays a key role in the reuptake of glucose in the proximal tubule of the kidneys. Ipragliflozin reduces blood glucose levels by inhibiting the reuptake of glucose by selectively inhibiting SGLT2.
=== Signs and diagnosis of osteoporosis === Osteoporosis is a condition in which the bones become weaker due to losing bone mass or density, these bones then become more fragile which often leads to fractures of the bone. Osteoporosis is often asymptomatic until a fracture occurs. Common indicators include back pain, loss of height, a stooped posture, and fractures resulting from minor falls or movements.
Sources: en.wikipedia.org
It is a short synthetic peptide built from seven amino acids: methionine, glutamic acid, histidine, phenylalanine and three prolines. The sequence derives from the 4-10 fragment of adrenocorticotropic hormone with an added proline-glycine-proline tail. No plant or animal extract is involved; the material is produced by solid-phase peptide synthesis.
It was developed in the Soviet Union during the early 1980s by groups at the Institute of Molecular Genetics in Moscow. Russian approval for intranasal use followed, and it has been marketed there since. Western laboratories encountered it mainly through translated literature and, later, through online research-chemical trade.
It holds a Russian registration as a prescription nasal product but has no approval from the European Medicines Agency or the United States Food and Drug Administration. Buyers outside Russia usually receive material sold strictly for laboratory research. That distinction matters because research-grade and pharmaceutical-grade products carry different documentation and testing expectations.
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.