A practical reference on Lyophilized powder: what it is, how it behaves, what the literature reports, and where the honest uncertainties sit.
This page was last updated on 2025-11-01 and is reviewed periodically as new material appears.
Identity and purity of Semax are established mainly by reversed-phase high-performance liquid chromatography coupled with mass spectrometry. The chromatographic trace gives a purity estimate as a percentage of total peak area, while electrospray or matrix-assisted laser desorption ionization confirms the molecular mass against the calculated value. Amino acid analysis and sequence-specific fragmentation provide further confirmation when a supplier's chain of custody is unclear. Vendors frequently quote a purity figure without stating the detection wavelength or the integration method, which limits how far one number can be compared with another.
Stability depends heavily on physical state. Lyophilized powder held dry, cold and dark retains its content over long periods, whereas dissolved peptide begins to change within days at room temperature. The most cited degradation route is oxidation of the methionine residue, which converts the peptide to a sulfoxide form that elutes differently on chromatography. Hydrolysis of amide bonds and adsorption onto container walls contribute smaller losses. Buffers that exclude oxygen from the headspace slow the oxidation pathway, but no single condition prevents all change indefinitely.
Practical handling follows from those properties. Bulk material is best divided into single-use portions soon after receipt, because each thaw exposes the whole container to moisture and temperature cycling. Vials should be allowed to reach room temperature before opening to prevent condensation on the powder. Low-binding plasticware reduces loss of dilute solutions, and sterile filtration is used when a preparation must remain free of microbial growth. Records of batch number, reconstitution date and storage history are what allow a later analytical result to be interpreted meaningfully.
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.
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.
| Property | Value | Notes |
|---|---|---|
| Typical purity specification | ≥ 95 % of peak area by HPLC | Some suppliers quote 98 % or higher |
| Identity confirmation | Mass spectrometry (electrospray or MALDI) | Observed mass is compared with the calculated mass |
| Common analytical method | Reversed-phase HPLC on a C18 column | Acetonitrile and water gradients with trifluoroacetic acid |
| Primary degradation route | Oxidation of the methionine residue | Yields a sulfoxide that separates cleanly on chromatography |
| Storage of dissolved material | Aliquoted and frozen at −20 °C or below | Single-use aliquots avoid repeated temperature cycling |
稳定性主要由水解与氧化两条路径支配。肽键在中性或弱酸性条件下相对稳定，遇到强碱或长时间高温则明显断裂；甲硫氨酸侧链容易被氧化成亚砜，使主峰前移并拉低实际含量。金属离子、光照和反复冻融会进一步促进降解或聚集。冻干粉在低温避光条件下可存放较长时间，配制后的水溶液通常需要冷藏并尽快用完。
纯度评估以反相高效液相色谱为主，通过主峰面积百分比给出粗略结果，再配合电喷雾质谱核对分子量。氨基酸分析可验证组成比例，手性色谱或毛细管电泳用于检查残基构型。常见杂质包括缺失序列的短肽、氧化产物与二聚体。由于多数市售品不附带完整检验报告，独立第三方检测常被用来核实标称值。
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.
Desorption electrospray ionization (DESI) is an ambient ionization technique that can be coupled to mass spectrometry (MS) for chemical analysis of samples at atmospheric conditions. Coupled ionization sources-MS systems are popular in chemical analysis because the individual capabilities of various sources combined with different MS systems allow for chemical determinations of samples. DESI employs a fast-moving charged solvent stream, at an angle relative to the sample surface, to extract analytes from the surfaces and propel the secondary ions toward the mass analyzer. This tandem technique can be used to analyze forensics analyses, pharmaceuticals, plant tissues, fruits, intact biological tissues, enzyme-substrate complexes, metabolites and polymers. Therefore, DESI-MS may be applied in a wide variety of sectors including food and drug administration, pharmaceuticals, environmental monitoring, and biotechnology.
Wittner (1962), historian on peace movements Peter Winn (1962), professor of history at Tufts University Richard Alba (1963), sociologist, professor at Graduate Center, CUNY David Berlinski (1963), mathematician, professor Eric Foner (1963), preeminent historian of Reconstruction, winner of the Pulitzer Prize for History and former president of American Historical Association David Orme-Johnson (1963), professor of psychology at the Maharishi University of Management Michael Klare (1963), professor of security studies at Hampshire College Victor Margolin (1963), professor of design history at the University of Illinois at Chicago Jonah Raskin (1963), writer, professor on counterculture Howard Spodek (1963), historian specializing in urban studies; professor at Temple University Robert J. Art (1964), professor of international relations at Brandeis University Richard P. Appelbaum (1964), professor of sociology at University of California, Santa Barbara Jonathan R. Cole (1964), sociologist and provost of Columbia University 1989–2003 Peter S. Donaldson (1964), professor of English literature at the Massachusetts Institute of Technology Richard Epstein (1964), libertarian law scholar Richard S. Kayne (1964), professor of linguistics at New York University Peter Kolchin (1964), professor at the University of Delaware and winner of the 1988 Bancroft Prize John H. Langbein (1964), Sterling Professor at Yale Law School Peter K.
== Definition, regulatory aspects == The International Council on Harmonisation of Technical Requirements for Registration of Pharmaceuticals for Human Use, a 2015 Swiss NGO of pharmaceutical companies and others, defined a contract research organization (CRO), specifically pertaining to clinical trials services as: "A person or an organization (commercial, academic, or other) contracted by the sponsor to perform one or more of a sponsor's trial-related duties and functions." It further details the sponsor's responsibilities in its good clinical practice guidelines:
Sources: en.wikipedia.org
This is due to the fact that hydrogen bonding between the polyoxyethylene and the water molecules breaks down at high temperature and polyoxyethylene becomes also insoluble in water. The phase transitions can also be largely influenced by the use of additives such as salts and alcohols. The interactions with salts are related to their ability to act as water structure makers (salting-out) or water structure breakers (salting-in). Salting-out salts increase the self-hydration of water through hydrogen bonding and reduce the hydration of the copolymers, thus reducing the critical micelle temperature and critical micelle concentration. Salting-in electrolytes reduce the water self-hydration and increase the polymer hydration, therefore increasing the critical micelle temperature and critical micelle concentration. The different salts have been categorized by the Hofmeister series according to their ‘salting-out’ power. Different phase diagrams characterizing all these transitions have been constructed for most poloxamers using a great variety of experimental techniques (e.g. SAXS, Differential scanning calorimetry, viscosity measurements, light scattering).
Lansoprazole was the second of the PPI drugs to reach the market, being launched in Europe in 1991 and the US in 1995. It has no substitutions at the benzimidazole but two substituents on the pyridine, methyl group at position 3 and a trifluoroethoxy group at position 4. The drug is a 1:1 racemate of the enantiomers dexlansoprazole and levolansoprazole. It is available in gastroresistant capsules and tablets as well as chewable tablets.
Veterinary pharmacies, sometimes called animal pharmacies, may fall in the category of hospital pharmacy, retail pharmacy or mail-order pharmacy. Veterinary pharmacies stock different varieties and different strengths of medications to fulfill the pharmaceutical needs of animals. Because the needs of animals, as well as the regulations on veterinary medicine, are often very different from those related to people, in some jurisdictions veterinary pharmacy may be kept separate from regular pharmacies.
Surgical or internal medicine Age range of patients Diagnostic or therapeutic Organ-based or technique-based Throughout history, the most important has been the division into surgical and internal medicine specialties. The surgical specialties are those in which an important part of diagnosis and treatment is achieved through major surgical techniques. The internal medicine specialties are the specialties in which the main diagnosis and treatment is never major surgery. In some countries, anesthesiology is classified as a surgical discipline, since it is vital in the surgical process, though anesthesiologists never perform major surgery themselves. Many specialties are organ-based. Many symptoms and diseases come from a particular organ. Others are based mainly around a set of techniques, such as radiology, which was originally based around X-rays. The age range of patients seen by any given specialist can be quite variable. Pediatricians handle most complaints and diseases in children that do not require surgery, and there are several subspecialties (formally or informally) in pediatrics that mimic the organ-based specialties in adults. Pediatric surgery may or may not be a separate specialty that handles some kinds of surgical complaints in children. A further subdivision is the diagnostic versus therapeutic specialties. While the diagnostic process is of great importance in all specialties, some specialists perform mainly or only diagnostic examinations, such as pathology, clinical neurophysiology, and radiology.
Sources: en.wikipedia.org
Suppliers normally quote a percentage of total chromatographic peak area, most often from reversed-phase HPLC. That figure says nothing about what the remaining percentage contains, and it depends on the detection wavelength used. A mass spectrometry result is a separate and stronger check on identity.
The methionine residue at the start of the chain is vulnerable to oxidation, producing a sulfoxide variant. Amide bonds can also hydrolyze, though more slowly under neutral conditions. Cold storage, oxygen exclusion and minimization of freeze-thaw cycles slow both processes but do not stop them.
A purity number on a certificate does not establish that a powder is the same product as a registered nasal medicine. Counter-ion content, residual solvents and peptide-related impurities may differ between the two. Independent verification is the only way to narrow that gap.
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.