The short version of lyophilized powder fits in a sentence. The long version — which is the one that helps — is below.
Reviewed 2026-04-20. Anything still debated is marked as such rather than presented as settled.
Published research covers ischemic stroke, traumatic brain injury, cognitive impairment, optic nerve conditions and attention-related measures. Much of the human evidence comes from small trials conducted in one country, which limits how far the results generalize. Animal models supply the larger share of the data, and effects seen in rodents do not transfer automatically to people. Reviews have noted that methodological reporting is often incomplete, making it difficult to pool results or compare treatment schedules across studies.
Pharmacokinetic accounts emphasize rapid breakdown. After intravenous dosing the intact peptide disappears from blood within minutes, and nasal delivery produces low but measurable concentrations. Metabolites rather than the parent molecule may account for part of the observed activity, although the relative contribution is unresolved. Dosing in the literature varies widely and no optimal schedule has been agreed. These gaps are regularly cited as a reason the findings have not produced broad clinical adoption beyond the original research setting.
Scientific literature on semax is unevenly distributed. A substantial share of published work originates from a small number of laboratories in Russia, while independent replication elsewhere is limited. Human data consist mostly of small trials with short follow-up, and several reported outcomes rely on subjective rating scales. Questions about how much intact peptide reaches the central nervous system after nasal administration, and how long it persists there, are still unresolved. The compound is best described as an active research subject rather than a settled pharmacological agent.
Semax is a synthetic heptapeptide with the sequence Met-Glu-His-Phe-Pro-Gly-Pro. It was derived from the ACTH(4-10) fragment, a short segment of adrenocorticotropic hormone that lacks the hormonal activity associated with the full-length peptide. Researchers at the Institute of Molecular Genetics in Moscow developed the compound during the 1980s. It has been registered as a pharmaceutical product in Russia and several neighbouring countries, where it is supplied as a nasal solution, and it is also sold internationally as a research chemical.
The proposed mechanism centres on neurotrophic signalling rather than direct receptor activation. Semax is reported to increase expression of brain-derived neurotrophic factor and nerve growth factor in several brain regions, and to shift the balance between excitatory and inhibitory neurotransmitter systems. Interaction with melanocortin receptors has been suggested because of the parent ACTH fragment. Many of these findings come from rodent studies, and the extent to which they translate to human physiology remains an open question.
| Property | Value | Notes |
|---|---|---|
| Primary research models | Rodent studies | Largest share of published data |
| Reported markers | BDNF and NGF expression | Measured mainly in animal tissue |
| Common administration | Intranasal | Matches the registered formulation |
| Blood residence time | Minutes | Rapid enzymatic degradation |
| Evidence quality | Small trials, limited replication | Noted repeatedly in reviews |
Quality documentation for research-grade peptide usually includes a certificate of analysis stating purity, identity, and residual counterion content. Batch-to-batch variation in purity and salt form is a recognized issue, and comparisons across suppliers require attention to the exact counterion, for example acetate versus trifluoroacetate. Sequence verification by tandem mass spectrometry provides stronger evidence than a single mass measurement. For any study reporting biological results, the analytical method and the measured purity should be stated explicitly. Independent verification of supplier claims is considered good practice.
Semax is supplied as a lyophilized powder that appears white to off-white. It dissolves readily in water, phosphate-buffered saline, and other aqueous media, which simplifies preparation of working solutions for laboratory use. The nasal products registered in Russia are dilute aqueous solutions, typically around 0.1 percent peptide by weight. Organic solvents are rarely necessary and can complicate handling. Because the peptide is hygroscopic, weighing should be performed quickly and with minimal exposure to ambient humidity.
Regulatory status varies sharply by country. Semax is registered for medical use in Russia, where it appears in formularies as a nasal solution, and it also holds registration in a small number of neighbouring states. It has no approval from the United States Food and Drug Administration or the European Medicines Agency, and it is not a scheduled controlled substance in most jurisdictions. Elsewhere it circulates mainly as laboratory material, so purity documentation comes from suppliers rather than from a national pharmacopoeia.
Semax is a synthetic peptide created in the Soviet Union during the early 1980s by researchers working in Moscow. It was built from the short adrenocorticotropic hormone fragment known as ACTH(4-10), and the chain was then extended with three additional amino acids. The resulting molecule was named semax and entered clinical use in Russia in 1994. It is generally described as a nootropic and neuroprotective agent rather than as a hormone analogue.
The parent fragment ACTH(4-10) carries the sequence Met-Glu-His-Phe-Arg-Trp-Gly. Semax replaces the arginine and tryptophan positions with a proline-glycine-proline tail, giving Met-Glu-His-Phe-Pro-Gly-Pro. That change removes residues associated with adrenal stimulation, so the peptide does not drive cortisol release the way full ACTH does. This distinction shapes how the compound is grouped in the literature, where it sits with neuropeptides and peptide neuromodulators rather than with corticosteroids.
Reaction of phthalic anhydride [85-44-9] (1) with 2-Amino-7-chloro-1,8-naphthyridine [15944-33-9] (2) with leads to the corresponding phthalimide. Selective reduction of one of the imide carbonyl groups give the corresponding alcohol, 2-(7-chloro-1,8-naphthyridin-2-yl)-3-hydroxyisoindolin-1-one [55112-38-4] (3). Reaction with the carbanion from Ethyl 5-methyl-3-oxohexanoate [57689-16-4] (4) leads to the product from the displacement of the hydroxyl group; 'this too may proceed via the acrylate obtained from aldol reaction of the ring opened imidal'. The product of this step is Ethyl 2-[2-(7-chloro-1,8-naphthyridin-2-yl)-3-oxo-1-isoindolinyl]-6-methyl-3-oxoheptanoate, PC9891305 (5).
Subsequent to its synthesis in the 1920s, pseudoephedrine was introduced for medical use as a decongestant. Pseudoephedrine is widely available over-the-counter (OTC) in both single-drug and combination preparations. Availability of pseudoephedrine has been restricted starting in 2005 as it can be used to synthesize methamphetamine. Phenylephrine has replaced pseudoephedrine in many over-the-counter oral decongestant products. However, oral phenylephrine appears to be ineffective as a decongestant. In 2023, pseudoephedrine was the 292nd most commonly prescribed medication in the United States, with more than 400,000 prescriptions. In 2023, the combination with brompheniramine and dextromethorphan was the 281st most commonly prescribed medication in the United States, with more than 700,000 prescriptions. In 2023, the combination with loratadine was the 300th most commonly prescribed medication in the United States, with more than 400,000 prescriptions.
Another common example is the reaction of a primary amine or secondary amine with a carboxylic acid or with a carboxylic acid derivative to form an amide. This reaction is widely used, especially in the synthesis of peptides. On the simple addition of an amine to a carboxylic acid, a salt of the organic acid and base is obtained. To overcome this, the carboxylic acid first needs to be "activated". This is usually done by converting the acid into a more reactive derivative (i.e. anhydride, acid halide) or by using a coupling agent. In some cases, high temperatures (>200 °C) can overcome salt formation by driving off water, without the need for "activation" of the carboxyl group. The downside to this simple reaction is that the compounds may decompose at these elevated temperatures. The carboxylic acid derivatives can be esters, anhydrides, acid halides or any other activated species. The choice of activated carboxyl group or coupling agent can be very important in peptide synthesis, as using the wrong one can lead to racemization.
=== Music === The game's original score was composed and produced by Rik Schaffer. Troika licensed many songs for the game, and posters for real bands are featured on the walls of the game's clubs. The soundtrack was released as a limited edition CD to customers who pre-ordered the game through Best Buy. It features nine tracks by artists including Daniel Ash, Chiasm, Tiamat, Darling Violetta, Genitorturers, and Lacuna Coil. "Bloodlines", performed by Al Jourgensen and Ministry, was composed and performed specifically for the game. Activision chose the licensed tracks without input from Troika. The song "Angel" by Massive Attack was used as a placeholder on the game's menu screen. Troika could not obtain the rights to use the song in the finished game and tasked Schaffer with creating something similar.
== Evidence == It has been demonstrated in animal experiments that there is an improvement in sorbitol levels and Na+/K+ ATPase activity leading to improved nerve conduction velocity. Diabetic rats treated with epalrestat showed improvement in morphological abnormalities of nerves. In a placebo controlled double blind trial of 196 patients, it was shown that Epalrestat in a dose of 150 mg/day improved the effects of diabetic neuropathy like upper limb spontaneous pain, motor nerve conduction velocity, thresholds of vibratory sensation and autonomic nerve function as compared to a placebo. These effects were significantly better in those with poorer control of diabetes. A systematic review and metaanalysis showed that based on the results of 10 articles, it can be concluded that Epalrestat has some benefit in the control of diabetic cardiovascular autonomic neuropathy but only in the early or mild cases. It also doesn't influence glycaemic control.
Sources: en.wikipedia.org
==== Biosynthesis ==== The biosynthetic route is based on the alkylation of the amino acid tryptophan with dimethylallyl diphosphate (isoprene derived from 3R-mevalonic acid) giving 4-dimethylallyl-L-tryptophan which is N-methylated with S-adenosyl-L-methionine. Oxidative ring closure followed by decarboxylation, reduction, cyclization, oxidation, and allylic isomerization yields D-(+)-lysergic acid. The biosynthetic pathway has been reconsituted in transgenic baker's yeast.
Shaka was succeeded by Dingane, his half-brother, who conspired with Mhlangana, another half-brother, and Mbopa, an induna, to murder him in 1828. Following this assassination, Dingane murdered Mhlangana, and took over the throne. One of his first royal acts was to execute all of his royal kin. In the years that followed, he also executed many past supporters of Shaka in order to secure his position. One exception to these purges was Mpande, another half-brother, who was considered too weak to be a threat at the time.
The following is a partial list of the "D" codes for Medical Subject Headings (MeSH), as defined by the United States National Library of Medicine (NLM). This list continues the information at List of MeSH codes (D10). Codes following these are found at List of MeSH codes (D12.644). For other MeSH codes, see List of MeSH codes. The source for this content is the set of 2006 MeSH Trees from the NLM.
== Locations == In addition to the main hospital in Raleigh, Rex Health Care has locations throughout Wake County. These include an outpatient rehabilitation and fitness center in Garner, outpatient facilities in Cary, Holly Springs (Holly Springs facility), and Wake Forest (Wakefield facility), and outpatient diagnostics in Cary, Wakefield, and Knightdale. Apex also has a rehabilitation and nursing care center that is run by Rex. In December 2021, Rex opened a new facility in Holly Springs offering multiple services.
=== Related prokaryotic systems === Gene expression in prokaryotes is influenced by an RNA-based system similar in some respects to RNAi. Here, RNA-encoding genes control mRNA abundance or translation by producing a complementary RNA that anneals to an mRNA. However these regulatory RNAs are not generally considered to be analogous to miRNAs because the Dicer enzyme is not involved. It has been suggested that CRISPR interference systems in prokaryotes are analogous to eukaryotic RNAi systems, although none of the protein components are orthologous.
Sources: en.wikipedia.org
The main proposal is modulation of neurotrophic factors such as brain-derived neurotrophic factor, supported largely by animal experiments. Receptor-level targets have not been firmly established. Most reviews describe the mechanism as only partially characterized.
The compound is registered as a medicine in Russia, so clinical work has concentrated there. Trials elsewhere are few and generally small. This geographic concentration is a recognized limitation in evidence reviews.
Some fraction may reach the central nervous system through olfactory pathways, and this is often cited as the rationale for the nasal route. The size of that fraction in humans is not well quantified. Blood concentrations after nasal dosing are low, which complicates measurement.
Semax is based on the ACTH(4-10) fragment, a seven-amino-acid segment of adrenocorticotropic hormone. The synthetic peptide retains the core sequence while removing regions associated with endocrine activity. This modification is intended to isolate effects on the nervous system.