If you have been reading about intranasal route and want a single page that covers the useful parts, this is it: definitions, context, how it is studied, and the questions that come up repeatedly.
Updated 2026-03-01. Numbers and descriptions here follow the published literature rather than marketing material.
Identity and purity are commonly assessed by reversed-phase high-performance liquid chromatography, with ultraviolet detection near 214 nanometers for the peptide backbone. Mass spectrometry, either electrospray or matrix-assisted laser desorption, confirms molecular mass and detects truncation or modification products. Amino acid analysis can verify composition. Because the sequence contains no strongly absorbing aromatic residue apart from phenylalanine, detection wavelengths are chosen carefully. Purity values above 95 percent are typical for research-grade material.
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.
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.
| Property | Value | Notes |
|---|---|---|
| Typical purity | ≥95% by HPLC | Research-grade material |
| Detection wavelength | 214 nm | Peptide bond absorbance |
| Reconstitution medium | Sterile water or saline | Prepare fresh or aliquot immediately |
| Storage (solution) | -80 °C, single-use aliquots | Avoid repeated freeze-thaw cycles |
| Common salt form | Acetate or trifluoroacetate | Affects mass and solubility |
Published research has focused mainly on neurological and cognitive endpoints in animal models, with proposed mechanisms involving brain-derived neurotrophic factor and related signalling pathways. A substantial share of the human data originates from a limited number of research groups, and independent replication in other countries remains sparse. Regulatory status reflects that distribution: the peptide is registered as a medicine in Russia and appears in some neighbouring markets, while elsewhere it is handled as a research chemical without approved therapeutic labelling. Questions about dose-response relationships, long-term effects, and comparability across studies are still open.
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.
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.
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.
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.
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.
== Education == James obtained her bachelor's degree in biology from Mills College in 1962, followed by an M.S. and Ph.D. from the University of California, Los Angeles in 1982 and 1986, respectively.
The specific matchups involving the third-place teams depended on which eight third-place teams qualified for the round of 32, but not on their relative rankings. The 495 possible combinations were published in Annex C of the tournament regulations. Because of the specific combination of qualified teams, option number 67 of annex C was applicable.
In one study, disk diffusion method proved concentration-dependent antifungal activity against Trichophyton, Microsporum and Epidermophyton, three of the most common species of dermatophytes that cause superficial fungal infections of human skin. Further research is needed, however, to examine the role of sangre de grado from Croton lechleri as an effective antifungal agent in animal and human models. Antiviral activity against influenza, parainfluenza, Herpes simplex viruses I and II, and Hepatitis A and B by Croton lechleri extracts and compounds have been exhibited. The most notable compound involved in antiviral activity is SP-303, also known as crofelemer, which has been heavily studied in vitro for its antiviral activity against the aforementioned viruses, as well as thymidine kinase mutants of HSV-1 and HSV-2 and acyclovir-resistant strains. Antidiarrhoeal Activity Crofelemer, a purified proanthocyanidin oligomer extracted from the sap of Croton lechleri has been investigated for potential antidiarrhoeal activity. Various clinical studies have confirmed significant improvement in acute E. coli and V. cholera diarrhea cases from the administration of crofelemer. In the context of the principal luminal membrane determinants of intestinal fluid secretion, the mechanism of crofelemer action involves the inhibition of apical membrane cAMP-stimulated (CFTR) and calcium-stimulated (CaCC) Cl− channels by crofelemer molecules, with little effect on cation channels or cAMP/calcium signaling.
Antithrombin is a serpin (serine protease inhibitor) and is thus similar in structure to most other plasma protease inhibitors, such as alpha 1-antichymotrypsin, alpha 2-antiplasmin and Heparin cofactor II. The physiological target proteases of antithrombin are those of the contact activation pathway (formerly known as the intrinsic pathway), namely the activated forms of Factor X (Xa), Factor IX (IXa), Factor XI (XIa), Factor XII (XIIa) and, to a greater extent, Factor II (thrombin) (IIa), and also the activated form of Factor VII (VIIa) from the tissue factor pathway (formerly known as the extrinsic pathway). The inhibitor also inactivates kallikrein and plasmin , also involved in blood coagulation. However it inactivates certain other serine proteases that are not involved in coagulation such as trypsin and the C1s subunit of the enzyme C1 involved in the classical complement pathway. Protease inactivation results as a consequence of trapping the protease in an equimolar complex with antithrombin in which the active site of the protease enzyme is inaccessible to its usual substrate. The formation of an antithrombin-protease complex involves an interaction between the protease and a specific reactive peptide bond within antithrombin. In human antithrombin this bond is between arginine (arg) 393 and serine (ser) 394 (see Figure 2 and Figure 3). It is thought that protease enzymes become trapped in inactive antithrombin-protease complexes as a consequence of their attack on the reactive bond.
Another application is in the diagnosis of tularemia. An evaluation of the Western blot's ability to detect antibodies against F. tularensis revealed that it has a sensitivity of almost 100% and a specificity of 99.6%. Some forms of Lyme disease testing employ Western blotting. A Western blot can also be used as a confirmatory test for hepatitis B infection and HSV-2 (herpes type 2) infection. In veterinary medicine, a Western blot is sometimes used to confirm FIV+ status in cats. Further applications of the Western blot technique include its use by the World Anti-Doping Agency (WADA). Blood doping is the misuse of certain techniques and/or substances to increase one's red blood cell mass, which allows the body to transport more oxygen to muscles and therefore increase stamina and performance. There are three widely known substances or methods used for blood doping, namely, erythropoietin (EPO), synthetic oxygen carriers and blood transfusions. Each is prohibited under WADA's List of Prohibited Substances and Methods. The Western blot technique was used during the 2014 FIFA World Cup in the anti-doping campaign for that event. In total, over 1000 samples were collected and analysed by Reichel, et al. in the WADA-accredited Laboratory of Lausanne, Switzerland. Recent research utilizing the Western blot technique showed an improved detection of EPO in blood and urine based on novel Velum SAR precast horizontal gels optimized for routine analysis.
Sources: en.wikipedia.org
=== Breaking the C-N bond and product release === The hydroxide ion joins with the carbon atom of the creatine's amidino group, creating a tetrahedral intermediate product. This intermediate product collapses and breaks the C-N bond, releasing urea. The remainder of the molecule rearranges to form sarcosine, and both products diffuse from the active site pocket.
Under the 1992 constitution, the president was elected by the Federal Assembly of Yugoslavia for a four-year term. After the constitutional amendments of 2000, direct elections for the office of President were introduced. Under the 2003 constitution, the president was once again elected by the Assembly of Serbia and Montenegro for a four-year term, this time at the proposal of the president and vice president of the assembly. The president of Serbia and Montenegro was a member of the Supreme Defence Council together with the president of Serbia and the president of Montenegro, and served automatically as chairman of the council of ministers. Previously, the president and the prime minister had to be from different republics; now, with the posts merged, the president of the assembly had to be from a different republic from the president of Serbia and Montenegro, who in turn could not come from the same republic for more than two consecutive terms of office. The results of the direct presidential elections of 2000 were as follows:
== Effects on diabetes == Purinergic receptors have been implicated in the vascular complications associated with diabetes due to the effect of high-glucose concentration on ATP-mediated responses in human fibroblasts.
== British and Commonwealth realms == In Commonwealth realms, including the United Kingdom, Canada, Australia and New Zealand, centenarians can receive congratulatory cards from the monarch, currently King Charles III, on their 100th birthday. In the UK, greeting cards are also sent by the monarch on every birthday beginning with the 105th. In Commonwealth realms in which the monarch does not ordinarily reside, honorees can also receive congratulations from the governor-general. In Canada, application must be made through the GGS official website. Similarly, in New Zealand, honorees must apply for greetings through the official government website.
== Further reading == Touraine, P. (2005). "Breast Inflammatory Gigantomastia in a Context of Immune-Mediated Diseases". Journal of Clinical Endocrinology & Metabolism. 90 (9): 5287–5294. doi:10.1210/jc.2005-0642. PMID 15972574. Oladele, AO; Olabanji, JK; Alabi, GH (2007). "Reduction mammoplasty: The experience in Ile-Ife, Nigeria". Nigerian Journal of Medicine. 16 (3): 261–267. PMID 17937167. Netscher, David T.; Mosharrafa, ALI M.; Laucirica, Rodolfo (1996). "Massive Asymmetric Virginal Breast Hypertrophy". Southern Medical Journal. 89 (4): 434–7. doi:10.1097/00007611-199604000-00019. PMID 8614890. U.S.A. Library of Congress - Healthy Breasts: A Primer John Blair Deaver (1917). The Breast: Its Anomalies, Its Diseases, and Their Treatment. P. Blakiston's Son & Co. p. 102. Joseph, Jacques (1987). Rhinoplasty and facial plastic surgery with a supplement on mammaplasty and other operations in the field of plastic surgery of the body: an atlas and textbook. Phoenix: Columella Press. p. 755. ISBN 0-9605972-1-2. Plummer, Samuel C.; Bump, Warner S. (1927). "Massive Hypertrophy of the Breasts". Annals of Surgery. 85 (1): 61–6. doi:10.1097/00000658-192701000-00008. PMC 1399262. PMID 17865606. Warren, John Collins (1900). The International text-book of surgery. Vol. II. Saunders. p. 234. Erichsen, John Eric (1885). The Science and art of surgery. Vol. II. H. C. Lea's Son & Company. pp. 693–694. Ochsner, Albert John (1921). Surgical Diagnosis and Treatment: By American Authors. Lea & Febiger. p. 147.
Sources: en.wikipedia.org
Solid peptide is best kept frozen at about minus 20 degrees Celsius in a sealed container with desiccant. It should be allowed to reach room temperature before opening to prevent condensation. Repeated warming and cooling of the same vial is discouraged.
Reversed-phase liquid chromatography establishes purity, while mass spectrometry confirms molecular mass. The two techniques are normally used together. Retention time alone is not sufficient evidence of identity.
Different counterions change the mass per unit of peptide and can shift chromatographic behavior. Two samples of equal stated purity may therefore not be directly comparable. Reports should specify the counterion whenever quantitative comparisons are made.
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.