lyophilised 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.
Updated 2025-12-12. Numbers and descriptions here follow the published literature rather than marketing material.
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.
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.
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.
| Property | Value | Notes |
|---|---|---|
| Typical analytical method | Reversed-phase HPLC with UV detection | Separates target peptide from truncated and oxidised forms |
| Identity confirmation | LC-MS or ESI-MS | Compares observed and calculated molecular ion |
| Primary degradation route | Methionine oxidation | Forms the sulfoxide; monitored as an early-eluting peak |
| Short-term storage | 2 to 8 degrees Celsius | Applies to working vials and reconstituted portions |
| Common synonyms | ACTH(4–10) analogue, MEHFPGP | Descriptive names used in laboratory catalogues |
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.
Circulation time for the peptide is short because peptidases cleave it readily. The Pro-Gly-Pro tail is thought to slow breakdown compared with the bare ACTH fragment, but the gain appears modest. Absorption after intranasal dosing is limited, and only a fraction of a dose is expected to reach the central nervous system. Laboratory concentrations therefore sit well above levels achieved systemically, a gap that complicates translation from bench findings to clinical claims.
Development took place during the 1980s at institutes of the Russian Academy of Sciences, where peptide fragments of ACTH were screened for cognitive and neuroprotective effects. The compound received regulatory approval in Russia as a nasal preparation, marketed for conditions such as ischemic stroke, transient ischemic attacks, and optic nerve disorders. Registration in other countries has not followed. Most published clinical reports originate from a small number of Russian research groups, and independent replication outside that setting remains limited. The regulatory status therefore differs sharply between Russia and the rest of the world.
Laboratory work points toward modulation of neurotrophic signaling, particularly expression of brain-derived neurotrophic factor and nerve growth factor in hippocampal tissue. Studies also describe effects on monoamine turnover, inflammatory mediators, and oxidative markers. These observations come mainly from animal models and cultured cells, so the causal chain in humans is not firmly established. Whether the reported molecular changes translate into measurable clinical benefit is an open question. Reviews generally present the mechanism as plausible rather than demonstrated.
Clinical evidence consists largely of small trials with modest sample sizes, often without independent replication. Reported endpoints include cognitive scores, recovery after stroke, and visual function, but study designs vary widely and few trials meet contemporary reporting standards. Systematic reviewers have noted a high risk of bias in several of these reports. No large multicenter trial conducted outside Russia has been published. The compound is therefore best described as investigational in most jurisdictions, with its clinical role still unresolved.
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.
Solid material is normally kept at minus 20 degrees Celsius in a sealed, desiccated container. Reconstituted solutions are less stable and are usually divided into single-use aliquots before freezing. Repeated freeze-thaw cycles are avoided because they promote aggregation and loss of activity. Light exposure is minimized by using amber glassware or foil wrapping. Published stability data for this peptide are sparse, so recommended storage conditions rest mainly on general practice for short synthetic peptides rather than on dedicated study.
研究兴趣主要集中在神经营养因子相关的路径上，包括脑源性神经营养因子与神经生长因子的表达变化。部分实验报告称在特定条件下观察到这些因子的水平上升，但具体信号通路和剂量依赖关系仍未完全厘清。多数公开数据来自细胞模型和动物实验，人体对照研究数量有限。因此，该化合物的作用机制在文献中属于活跃讨论，而非已经确立的定论。
Semax 是一种人工合成的七肽，氨基酸序列为 Met-Glu-His-Phe-Pro-Gly-Pro，单字母缩写记作 MEHFPGP。它被归类为促肾上腺皮质激素片段 ACTH(4-10) 的结构类似物，但并不天然存在于生物体内。母体片段 ACTH(4-10) 的序列为 Met-Glu-His-Phe-Arg-Trp-Gly，Semax 替换了中间两个残基，并在羧基端延长了 Pro-Gly-Pro 三肽。这种延长被普遍认为能提升分子对肽酶的耐受性。
该化合物于二十世纪八十年代在俄罗斯被开发，相关工作由俄罗斯科学院分子遗传学研究所的研究团队主导。开发目标并非复制 ACTH 的完整激素活性，而是寻找保留其神经作用方向、同时去除促肾上腺皮质激素释放效应的短肽片段。研究记录显示，这一方向促成了多个相关短肽的合成与筛选，而 Semax 是其中被研究最广泛的一个。当地文献常以 Семакс 这一名称指代它。
The common octopus (Octopus vulgaris) is a mollusk belonging to the class Cephalopoda. Octopus vulgaris is one of the most studied of all the octopus species, and also one of the most intelligent. It ranges from the eastern Atlantic, extends from the Mediterranean Sea, Black sea and the southern coast of England, to the southern coast of South Africa. It also occurs off the Azores, Canary Islands, and Cape Verde Islands. The species is also common in the Western Atlantic.
==== AP1 ==== Activation of AP1 factor involves three MAPK signaling pathways. These pathways use a phosphorylation cascade of three successive acting protein kinases to transmit a signal. The three MAPK pathways in T cells involve kinases of different specificities belonging to each of the MAP3K, MAP2K, MAPK families. Initial activation is done by the GTPase Ras or Rac which phosphorylate the MAP3K. A cascade involving the enzymes Raf, MEK1, ERK results in the phosphorylation of Jun, conformational change allows Jun to bind to Fos and hence AP-1 to form. AP-1 then acts as transcription factor. Raf is activated via the second messenger DAG, SOS, and Ras. DAG recruits among other proteins the RAS guanyl nucleotide-releasing protein (RasGRP), a guanine nucleotide exchange factor (GEF), to the membrane. RasGRP activates the small GTPase Ras by exchanging guanosine diphosphate (GDP) bound to Ras against guanosine triphosphate (GTP). Ras can also be activated by the guanine nucleotide exchange factor SOS which binds to the LAT signalosome. Ras then initiates the MAPK cascade. The second MAPK cascade with MEKK1, JNKK, JNK induces protein expression of Jun. Another cascade, also involving MEKK1 as MAPK3, but then activating MKK3 /6 and p38 induces Fos transcription. Activation of MEKK1, additionally to being activated by Ras, involves Slp-76 recruiting the GEF Vav to the LAT signalosome, which then activates the GTPase Rac. Rac and Ras activate MEKK1 and thereby initiate the MAPK cascade.
Eicosanoids include prostaglandins that produce fever and the dilation of blood vessels associated with inflammation and leukotrienes that attract certain white blood cells (leukocytes). Common cytokines include interleukins that are responsible for communication between white blood cells; chemokines that promote chemotaxis; and interferons that have antiviral effects, such as shutting down protein synthesis in the host cell. Growth factors and cytotoxic factors may also be released. These chemicals recruit immune cells to the site of infection and promote the healing of any damaged tissue following the removal of pathogens.
=== Male self-perception === Males may quite easily underestimate the size of their own penis relative to those of others. A survey by sexologists showed that many men who believed that their penis was of inadequate size had average-sized penises. Another study found sex education of standard penile measurements to be helpful and relieving for patients concerned about small penis size, most of whom had incorrect beliefs of what is considered medically normal. The study found that almost all of their patients that were concerned about their penis size overestimated the average penis size. The perception of having a large penis is often linked to higher self-esteem. Fears of shrinking of the penis in folklore have led to a type of mass hysteria called penis panic, though the penis legitimately can shrink in size due to scar tissue formation in the penis from a medical condition called Peyronie's disease. Marketers of penis enlargement products exploit fears of inadequacy, but there is no consensus in the scientific community of any non-surgical technique that permanently increases either the thickness or length of the erect penis that already falls into the normal range. Small penis syndrome (SPS), a term sometimes used in medical literature, is characterized by an obsessive concern that the penis is smaller than average, often despite normal measurements. It has been associated with wider psychological disorders, including anxiety and body dysmorphic disorder. Assessment focuses on confirming normality and addressing underlying psychological factors.
Sources: en.wikipedia.org
== Awards and honours == Hopkins was elected a Foreign Associate of the National Academy of Sciences (USA) in 1924. During his life, in addition to the Nobel Prize, Hopkins was awarded the Royal Medal of the Royal Society in 1918, the Cameron Prize for Therapeutics of the University of Edinburgh in 1922, and the Copley Medal of the Royal Society in 1926. Other significant honours were his election in 1905 as a Fellow of the Royal Society (FRS), Great Britain's most prestigious scientific organisation; his knighthood by King George V in 1925; and the award in 1935 of the Order of Merit, Great Britain's most exclusive civilian honour. From 1930 to 1935, he served as president of the Royal Society and, in 1933, served as president of the British Association for the Advancement of Science. He was elected to the American Philosophical Society in 1937.
A protease (also called a peptidase, proteinase, or proteolytic enzyme) is an enzyme that catalyzes proteolysis, breaking down proteins into smaller polypeptides or single amino acids, and spurring the formation of new protein products. They do this by cleaving the peptide bonds within proteins by hydrolysis, a reaction where water breaks bonds. Proteases are involved in numerous biological pathways, including digestion of ingested proteins, protein catabolism (breakdown of old proteins), and cell signaling. In the absence of functional accelerants, proteolysis would be very slow, taking hundreds of years. Proteases can be found in all forms of life including viruses. They have independently evolved multiple times, and different classes of protease can perform the same reaction by completely different catalytic mechanisms.
== Ductal cell physiology == While ductal cells are a minor type of cell in the adult pancreas, they have a critical function besides making the network that transfers enzymes from acini to the digestive tract. The primary function of pancreas ductal cells is to secrete a bicarbonate-rich, isotonic fluid. This fluid washes away the inactive form of digestive enzymes in the ductal system, neutralizes stomach acidity and mucins, and creates a pH environment necessary for the pancreas's normal function. Multiple factors affect the rate of bicarbonate secretion: species, cell location in the ductal system, secretory rate, etc. When stimulated, bicarbonate levels can get to 140mM. Due to this, there is a contrast in concentration between the outside and inside environment of ductal cells. The channels and ion transporters on ductal cells vary on the luminal and basolateral membrane, meaning there is functional polarization of the ductal cell. The largest network branches in this system contain goblet cells that interact with ductal cells, making up about 2% of this structure—these cells aid mucin assembly. Furthermore, unlike other exocrine glands, the pancreas does not have myoepithelial cells around the ducts. Ductal cells have a single cilium that is made up of nine peripheral doublets but does not have a central microtubule. This cilium is considered vital for perceiving flow in ducts.
Sources: en.wikipedia.org
=== Subtypes === There are several subtypes of catatonia recognized: stuporous catatonia, excited catatonia, malignant catatonia, and periodic catatonia. Subtypes are defined by the group of symptoms and associated features that a person is experiencing or displaying. Although catatonia can be divided into subtypes, its presentation is often dynamic, and the same individual may exhibit different subtypes at different times. Stuporous catatonia is characterized by immobility, mutism, and a lack of response to the world around them. They may appear frozen in one position for long periods of time unable to eat, drink, or speak. Excited catatonia is characterized by odd mannerisms and gestures, purposeless or inappropriate actions, excessive motor activity, restlessness, stereotypy, impulsivity, agitation, and combativeness. Patients suffering from excited catatonia may have speech and actions that are repetitive or mimic another person's. This state is often characterized by hyperactivity, and the patient may have delusions and hallucinations. Malignant catatonia is characterized by fever, dramatic and rapid changes in blood pressure, increased heart rate and respiratory rate, and excessive sweating. This condition is life-threatening, and the patient's laboratory tests may come back abnormal. Periodic catatonia is characterized by a person having recurrent episodes of catatonia. Individuals will experience multiple episodes over time, with no signs of catatonia between episodes.
John Scudder Sr., established the Christian Medical College and Hospital in Vellore in 1900, which has since become one of India's leading medical institutions. The Scudder family's enduring commitment to healthcare and education has left a lasting impact on India's social and medical landscape, inspiring generations of missionaries and healthcare professionals. The YMCA played a significant role in encouraging the development of sport in the princely states, as well as helping to improve agricultural output in rural areas.
In mammals, blood is in equilibrium with lymph, which is continuously formed in tissues from blood by capillary ultrafiltration. Lymph is collected by a system of small lymphatic vessels and directed to the thoracic duct, which drains into the left subclavian vein, where lymph rejoins the systemic blood circulation.
Sources: en.wikipedia.org
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.
Oxidation of the methionine residue to the sulfoxide is a frequently reported change, and it usually appears as an earlier-eluting peak in reversed-phase chromatography. Backbone hydrolysis products can also accumulate in aqueous solution.
Liquid chromatography coupled with mass spectrometry is the usual approach, because the observed molecular ion can be compared with a calculated mass of about 813.9 Da. Retention time alone does not establish identity.
Registered medical products are most often 0.1% nasal drops. Research suppliers ship lyophilized powder, usually in milligram quantities, which is dissolved before use. The active peptide is the same in both cases; presentation and excipients differ.