Everything below concerns lyophilization. We keep the language plain, cite what the science says, and separate well-supported claims from open questions.
Last reviewed on 2025-12-24. Where a claim depends on a specific study, the study is described rather than over-claimed.
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.
Lyophilized material is chemically stable for extended periods when kept dry, cold, and protected from light. The powder is hygroscopic, so vials should be warmed to room temperature before opening to reduce condensation on the contents. Once dissolved, the peptide is far less stable because peptide bonds are susceptible to hydrolysis and the methionine residue can oxidize. Solutions are typically aliquoted and held at 2-8 °C for short intervals or frozen for longer ones, and repeated freeze-thaw cycles should be avoided.
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.
| Property | Value | Notes |
|---|---|---|
| Molecular formula | C37H51N9O10S | Free acid form of the heptapeptide; depends on terminal groups |
| Molecular mass | About 813.9 g/mol | Average mass used for mass spectrometry confirmation |
| Appearance | White to off-white solid | Supplied as a lyophilised powder; hygroscopic |
| Solubility class | Freely soluble in aqueous media | Water, saline, and phosphate buffers; limited organic solubility |
| Typical storage temperature | -20 degrees Celsius | Long term and dry; short working periods may use 2 to 8 degrees Celsius |
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 mechanisms attributed to semax are inferred from animal and cell studies rather than traced to one confirmed target. The most frequently cited pathway involves increased expression of brain-derived neurotrophic factor and nerve growth factor in hippocampal and cortical tissue. Some work points to engagement of melanocortin receptors, particularly MC4, which the parent ACTH fragment can activate. Effects on dopaminergic and serotonergic signalling have also been reported. No single account explains all observed results, and the relative weight of each pathway remains unsettled.
Published studies examine a fairly narrow set of endpoints. Rodent experiments commonly measure maze learning, infarct volume after induced ischemia, and tissue levels of neurotrophic factors. Clinical reports from Russian centres describe attention, memory and recovery scores in patients after stroke or transient ischemic attack. Most of those human studies are small and few have been repeated by independent groups. Outcome measures differ between studies, which limits direct comparison.
Xi has called China–United States relations in the contemporary world a "new type of great-power relations", a phrase the Obama administration had been reluctant to embrace. Xi has indirectly spoken out critically on the U.S. "strategic pivot" to Asia. Relations with the U.S. soured after Donald Trump became president in 2017. Since 2018, U.S. and China have been engaged in an escalating trade war. In 2020, the relations further deteriorated due to the COVID-19 pandemic.
From May 2004 to April 2012, Surya Mohapatra served as the company's President and CEO. In 2007 Quest acquired diagnostic testing equipment company AmeriPath. In response to Mohapatra's resignation after eight years with Quest, former Philips Healthcare CEO Stephen Rusckowski was appointed. Under Rusckowski, Quest Diagnostics teamed up with central New England's largest health care system, UMass Memorial Health Care, to purchase its clinical outreach laboratory.
"I called this idea the central dogma, for two reasons, I suspect. I had already used the obvious word hypothesis in the sequence hypothesis, and in addition I wanted to suggest that this new assumption was more central and more powerful. ... As it turned out, the use of the word dogma caused almost more trouble than it was worth. Many years later Jacques Monod pointed out to me that I did not appear to understand the correct use of the word dogma, which is a belief that cannot be doubted. I did apprehend this in a vague sort of way but since I thought that all religious beliefs were without foundation, I used the word the way I myself thought about it, not as most of the world does, and simply applied it to a grand hypothesis that, however plausible, had little direct experimental support."
Sources: en.wikipedia.org
== Clinical pharmacology == Although the drugs omeprazole, lansoprazole, pantoprazole, and rabeprazole share common structure and mode of action, each differs somewhat in its clinical pharmacology. Differing pyridine and benzimidazole substituents result in small, but potentially significant different physical and chemical properties. Direct comparison of pantoprazole sodium with other anti-secretory drugs showed that it was significantly more effective than H2-receptor antagonists and either equivalent or better than other clinically used PPIs. Another study states rabeprazole undergoes activation over a greater pH range than omeprazole, lansoprazole, and pantoprazole, and converts to the sulphenamide form more rapidly than any of these three drugs. Most oral PPI preparations are enteric-coated, due to the rapid degradation of the drugs in the acidic conditions of the stomach. For example omeprazole is unstable in acid with a half-life of 2 min at pH 1–3, but is significantly more stable at pH 7 (half-life ca. 20 h). The acid protective coating prevents conversion to the active principle in the lumen of the stomach, which then will react with any available sulfhydryl group in food and will not penetrate to the lumen of the secretory canaliculus The oral bioavailability of PPIs is high; 77% for pantoprazole, 80–90% for lansoprazole and 89% for esomeprazole. All the PPIs except tenatoprazole are rapidly metabolized in the liver by CYP enzymes, mostly by CYP2C19 and CYP3A4. PPIs are sensitive to CYP enzymes and have different pharmacokinetic profiles.
Kecap manis: Sweetened soy sauce, which has a thick syrupy consistency and a unique, pronounced, sweet, somewhat treacle-like flavor due to generous addition of palm sugar. Regular soy with brown sugar and a trace of molasses added can substitute. It is by far the most popular type of soy sauce employed in Indonesian cuisine, accounts for an estimated 90 percent of the nation's total soy sauce production. Kecap manis is an important sauce in Indonesian signature dishes, such as nasi goreng, mie goreng, satay, tongseng and semur. Sambal kecap for example is type of sambal dipping sauce of kecap manis with sliced chili, tomato and shallot, a popular dipping sauce for sate kambing (goat meat satay) and ikan bakar (grilled fish/seafood). Since soy sauce is of Chinese origin, kecap asin is also an important seasoning in Chinese Indonesian cuisine. Kecap manis sedang: Medium sweet soy sauce, which has a less thick consistency, is less sweet and has a saltier taste than kecap manis. Kecap asin: Regular soy sauce derived from the Japanese shoyu, but usually more concentrated and thicker, with a darker color and stronger flavor; it can be replaced by Chinese light soy sauce in some recipes. Salty soy sauce was first introduced into Indonesia by Hokkien people so its taste resembles that of Chinese soy sauce. Hakka soy sauce made from black beans is very salty and large productions are mainly made in Bangka Island.
The city and the metropolitan area has a dense transport network. This solves the problem of a break between the lower town and the upper town and the two parts of the city are connected by long boulevards, winding roads, many stairs, a funicular and the Jenner tunnel. The CODAH transport network is called Lia and is operated by the Ocean Port Transport company (CTPO), a subsidiary of Veolia Transport. The overhaul of the bus network in 2008 helped to ensure a better service for all the towns in the metropolitan area. The CTPO operates a bus network consisting of 19 regular urban routes and six evening routes called the "Midnight Bus". The Le Havre urban area is served by 165 vehicles and 41 regular bus routes with an average of 100,000 passengers per day. From January 2011 there has been a regular shuttle service specific to the Industrial Zone and Port of Le Havre, thus adding to the cross-estuary service of VTNI. Since 1890 the funicular has provided a link between the upper town and the lower town in four minutes with a cable car. Le Havre had a tramway system from 1894 until it closed in 1957. More recently a new tramway system, with 23 stations and 13 km (8 mi) of route, was built, and opened on 12 December 2012. The first part of the line connects the beach to the station climbing to the upper town through a new tunnel near the Jenner tunnel then it splits into two: one link going to Mont-Gaillard, the other to Caucriauville.
Sources: en.wikipedia.org
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.
It appears in Russian pharmaceutical listings as a nasal formulation, but it is not an authorised medicine in the United States or the European Union. Outside those markets it is normally encountered as a research chemical rather than a prescription product.
Laboratory and animal work points to melanocortin signalling and changes in neurotrophic factor levels, especially brain-derived neurotrophic factor. The exact receptor targets and the degree to which these findings transfer to humans are still unresolved.
Dry powder is normally held at -20 °C or lower, away from light and moisture. Sealed vials can also be kept at 2-8 °C for shorter intervals. Warming to room temperature before opening prevents condensation.