intranasal delivery 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 2026-08-01. Numbers and descriptions here follow the published literature rather than marketing material.
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.
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 |
|---|---|---|
| Appearance | White to off-white powder | Lyophilized solid from research suppliers |
| Solubility | Freely soluble in water | Also dissolves in aqueous buffers; solutions are used fresh |
| Typical storage temperature | -20 °C for lyophilized powder | Short-term transport at 2-8 °C is common |
| Common analytical method | Reverse-phase HPLC | Paired with mass spectrometry for identity confirmation |
| Common synonyms | ACTH(4-10) analogue; MEHFPGP | N-terminal methionine retained in the chain |
溶液状态的稳定性明显低于冻干粉。肽类在水溶液中可能经历水解、氧化与聚集，其中甲硫氨酸和天冬酰胺等残基常是敏感位点。Semax 含有甲硫氨酸，因此氧化风险相对突出。工作液一般主张现配现用，或冷藏并在数日内用尽。缓冲液种类、pH 和离子强度都会影响降解速率，而关于最佳条件的公开数据并不统一。
常规纯度与身份确认依赖反相高效液相色谱，并辅以质谱测定分子量。氨基酸组成分析可用于验证序列构成，肽图分析则能进一步定位修饰或降解产物。杂质谱通常关注缺失序列肽、截短片段和氧化产物。不同方法的检出限并不相同，因此各实验室报告的纯度数值不宜直接横向比较。
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.
=== Diabetes === Januvia (sitagliptin) ($1.3 billion in 2024 revenues) is a dipeptidyl peptidase IV inhibitor for the treatment of type 2 diabetes. In 2013, Januvia was the second largest selling diabetes drug worldwide. It has been popular due in part because unlike many other diabetes drugs, it causes little or no weight gain and is not associated with hypoglycemic episodes. There has been some concern that treatment with Januvia and other DPP-IV inhibitors may be associated with a modestly increased risk of pancreatitis. Janumet ($1.0 billion in 2024 revenues) is a single pill combination drug containing both Januvia and metformin.
==== United States ==== In the United States, tianeptine is not considered by the Drug Enforcement Administration as a controlled substance or analogue thereof. However, its use in dietary supplements and food is unlawful. The Food and Drug Administration (FDA) has issued warnings, as recently as January 2024, about the dangers of recreational tianeptine use and the risks posed by adulterated dietary supplements containing undeclared tianeptine. On 6 April 2018, Michigan became the first US state to outlaw tianeptine sodium, classifying it as a schedule II controlled substance. The scheduling of tianeptine sodium is effective 4 July 2018. On 1 November 2019, Tianeptine became a Schedule II controlled dangerous substance as classified within the Uniform Controlled Dangerous Substances Act of the state of Oklahoma. On 15 March 2021, Alabama outlawed tianeptine, initially classifying it as a schedule II controlled substance. It was later reclassified as a schedule I controlled substance on 14 November 2021. On 1 July 2022, Tennessee outlawed tianeptine and adds "any salt, sulfate, free acid, or other preparation of tianeptine, and any salt, sulfate, free acid, compound, derivative, precursor, or preparation thereof that is substantially chemically equivalent or identical with tianeptine", classifying it as a schedule II controlled substance. On 22 December 2022, Ohio outlawed tianeptine, classifying it as a schedule I controlled substance with Ohio Governor Mike DeWine referencing the widespread availability of the chemical there as "gas-station heroin".
Trump gave a speech, saying "we've never gotten along better" and as a "special treat", Xi and Peng could be the first ones to enter the White House State Ballroom, stating "Anybody who wants to walk into a construction site that's nice and clean and sparkling, it's our honor to have you do so". He said "Tonight, we revive the spirit of that first encounter here on American soil as we are joined by some of the top leaders in business, culture and government from our own time" and added "On one side, China draws on thousands of years of history and tradition from Sun Tzu to Sun Yat-sen. For Americans, we inherit a legacy of faith from Jerusalem to Rome, democracy of ancient Athens, the triumphs of Sparta and the freedom proclaimed in Philadelphia 250 years ago". He celebrated the two nations' "foundation of commerce and mutual respect", adding "President Xi and I both understand that we represent different systems, but the ties between our people endure" and that "Americans and Chinese have always exchanged goods, knowledge, customs, and ideas. This has been the foundation of commerce and mutual respect between our countries, and together we can continue to build a relationship that promotes prosperity and security for future generations". A three‑foot tall sculpture of a bald eagle was unveiled and gifted to Xi, which Trump described as a symbolic "embodiment of the free and soaring spirit of America."
Sources: en.wikipedia.org
=== Components === Cells: Chondrocytes are an obvious choice to use in the regeneration of cartilage due to their ability to secrete collagen and other ECM components necessary for the functional properties of cartilage. Chondrocytes can be harvested from a non-weight bearing joint space of an individual and cultured. Unfortunately, chondrocytes harvested from individuals may dedifferentiate and lose their properties. Additionally, aging chondrocytes show less metabolic activity and may not produce functional proteins or not enough functional proteins to create a desired ECM. Mesenchymal stem cells can also be used to create chondrocytes and make cartilage regeneration possible. Growth factors: Growth factors can be used to induce differentiation of a cell or induce secretion of matrix proteins. Common growth factors for the application of synthetic cartilage include Insulin-growth factor 1 (IGF-1), Transforming Growth Factor β (TGF- β), Bone Morphogenic Proteins (BMP) and Growth and Differentiation Factor 5 (GDF-5). Human induced pluripotent stem cells (iPSCs) are an alternative cell source that have the potential to self-renew and provide an almost unlimited number of cells with pluripotent capabilities, or the ability to differentiate into many different cell types. Bioinks: these are the materials used to engineer artificial live tissue using 3D printing technology. Bioinks can be composed solely of cells, but are usually a combination of cells and a carrier material, often a biopolymer gel.
== Variants == A common variant is Lillie's trichrome, which uses aniline blue instead of a green dye. It is often erroneously called Masson's trichrome. It differs in the dyes used, their concentrations, and the immersion times. Another common variant is the Masson trichrome & Verhoeff stain, which combines the Masson trichrome stain and Verhoeff's stain. This combination is useful for the examination of blood vessels; the Verhoeff stain highlights elastin (black) and allows one to easily differentiate small arteries (which typically have at least two elastic laminae) and veins (which have one elastic lamina).
This test can be used to measure the aggregate modulus of cartilage, which is typically in the range of 0.5 to 0.9 MPa for articular cartilage, and the Young's Modulus, which is typically 0.45 to 0.80 MPa. The aggregate modulus is "a measure of the stiffness of the tissue at equilibrium when all fluid flow has ceased", and Young's modulus is a measure of how much a material strains (changes length) under a given stress. The confined compression test can also be used to measure permeability, which is defined as the resistance to fluid flow through a material. Higher permeability allows for fluid to flow out of a material's matrix more rapidly, while lower permeability leads to an initial rapid fluid flow and a slow decrease to equilibrium. Typically, the permeability of articular cartilage is in the range of 10^-15 to 10^-16 m^4/Ns. However, permeability is sensitive to loading conditions and testing location. For example, permeability varies throughout articular cartilage and tends to be highest near the joint surface and lowest near the bone (or "deep zone"). Permeability also decreases under increased loading of the tissue. Indentation testing is an additional type of test commonly used to characterize cartilage. Indentation testing involves using an indentor (usually <0.8 mm) to measure the displacement of the tissue under constant load. Similar to confined compression testing, it may take hours to reach equilibrium displacement. This method of testing can be used to measure the aggregate modulus, Poisson's ratio, and permeability of the tissue.
Analysis of the debris at the test site of the United States' first thermonuclear weapon, Ivy Mike (1 November 1952, Enewetak Atoll), besides einsteinium, fermium, plutonium and americium also revealed isotopes of berkelium, californium and curium, in particular 245Cm, 246Cm and smaller quantities of 247Cm, 248Cm and 249Cm. Atmospheric curium compounds are poorly soluble in common solvents and mostly adhere to soil particles. Soil analysis revealed about 4,000 times higher concentration of curium at the sandy soil particles than in water present in the soil pores. An even higher ratio of about 18,000 was measured in loam soils. The transuranic elements up to fermium, including curium, should have been present in the natural nuclear fission reactor at Oklo, but any quantities produced then would have long since decayed away.
Sources: en.wikipedia.org
It consists mainly of animal experiments and small clinical reports, with much of the clinical material published in Russian-language journals. Large independent trials are scarce. Separating reliable effects from chance findings is consequently difficult.
A fraction of an intranasal dose is thought to reach the central nervous system, and this route is favoured partly for that reason. The proportion is not well characterized. Direct measurement in humans remains difficult with current methods.
Raised BDNF and NGF expression has been reported across several animal studies, which makes the signal fairly consistent. Whether the same change occurs in humans at usable doses is not established. It is best treated as a working hypothesis rather than a confirmed clinical mechanism.
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.