Electrospray ionization comes up often in conversation and rarely with the context attached. Here we lay out the basics in order, then work through the practical considerations.
Updated 2026-07-06. Numbers and descriptions here follow the published literature rather than marketing material.
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.
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。
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。
| Property | Value | Notes |
|---|---|---|
| Solid storage temperature | -20 °C or below | Desiccated and protected from light |
| Solution storage temperature | -80 °C as single-use aliquots | Avoid repeated freeze-thaw cycles |
| Purity assessment method | RP-HPLC, around 214 nm | Reported as main-peak area percent |
| Identity confirmation method | ESI-MS or MALDI-TOF | Measured mass compared with calculated mass |
| Common synonyms | ACTH(4-10) analog; Met-Glu-His-Phe-Pro-Gly-Pro | Also written as Semaxum in some sources |
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.
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.
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.
=== Legal status === In Canada, amphetamines are in Schedule I of the Controlled Drugs and Substances Act, and can only be obtained by prescription. In Japan, the use, production, and import of any medicine containing amphetamines is prohibited. In South Korea, amphetamines are prohibited. In Taiwan, amphetamines including Adderall are Schedule 2 drugs with a minimum five-year prison term for possession. On the contrary, Ritalin can be legally prescribed as a form of treatment of ADHD. In Thailand, amphetamines are classified as Type 1 Narcotics. In the United Kingdom, amphetamines are regarded as Class B drugs. The maximum penalty for unauthorized possession is five years in prison and an unlimited fine. The maximum penalty for illegal supply is 14 years in prison and an unlimited fine. In the United States, amphetamine is a Schedule II prescription drug, classified as a central nervous system (CNS) stimulant. Internationally, amphetamine is in Schedule II of the Convention on Psychotropic Substances.
ELGA LabWater is the laboratory water brand name of Veolia Water Solutions & Technologies. ELGA manufactures, supplies and services water purification systems for use in general, R&D, healthcare and clinical laboratories. Its offices and distributors are located in more than 60 countries.
== Average mass == The average mass of a molecule is obtained by summing the average atomic masses of the constituent elements. For example, the average mass of natural water with formula H2O is 1.00794 + 1.00794 + 15.9994 = 18.01528 Da.
Sources: en.wikipedia.org
== Medical career == In 1955 he joined the IDF and graduated an Artillery officers training course. He then began his academic studies at the Hadassah school of Medicine in Jerusalem. After his graduation he started Orthopedics under Dr Ernst Spira and was posted as a military doctor in the 52nd brigade of the Armored Corps. In 1965 he moved to New York to specialize in Orthopaedic Surgery at the Mount Sinai School of Medicine and the Albert Einstein College of Medicine under Professor Arthur Helfet. At the end of his training he studied Artificial Hip Joint replacement under Professor Philip Wilson II at the Cornell University Hospital for Special Surgery. He then moved to the Lenox Hill Hospital where he established the Hip Surgery clinic with Dr James Nicholas. During his time in New York, he lectured at Albert Einstein, Mount Sinai, Elmhurst and the Brooklyn Children’s hospitals. During the wars in Israel, Six Days War (1967) and Yom Kippur War (1973) he volunteered as a surgeon in the IDF Medical corps. In 1975 he returned to Israel to take up the position of Head of the Orthopaedic Surgery at Bnai Zion Hospital in Haifa. Mendes ran the department of Orthopaedic Surgery until his retirement in 2002. His department offered a variety of innovative surgical procedures to patients from the entire country. Care was given to elderly, adults and infants for Orthopedic diseases benign and malignant and for injuries ranging from sports accidents to war casualties including rehabilitation of amputees.
Yaws is typically found in humid tropical forest regions in South America, Africa, Asia, and Oceania. Yaws primarily affects children, with up to 80% of cases in those under 15 years of age, and peak incidence in children aged six to ten. Boys and girls are impacted equally. It is more common in remote areas, where access to treatment is poorer. It is associated with poverty and poor sanitation facilities and personal hygiene. Worldwide, almost 85% of yaws cases are in Ghana, Papua New Guinea, and the Solomon Islands. Rates in sub-Saharan Africa are low but tend to be concentrated in specific populations. As of 2015, it is estimated that about 89 million people live in yaws-endemic areas, but data are poor, and this is likely an overestimate. In the early 1900s, yaws was very common; in sub-Saharan Africa, it was more frequently treated than malaria, sometimes making up more than half of treatments. Mass treatment campaigns in the 1950s reduced the worldwide prevalence from 50 to 150 million to fewer than 2.5 million; however, during the 1970s, there were outbreaks in South-East Asia, and there have been continued sporadic cases in South America. As of 2011, it was unclear how many people worldwide were currently infected. From 2008 to 2012, 13 countries reported over 300,000 new cases to the WHO. There was no system for certifying local elimination of yaws, and it is not known whether the lack of reports from some countries is because they stopped having yaws cases or because they stopped reporting them.
Sendai virus is used as a backbone for vaccine development against Mycobacterium tuberculosis that causes tuberculosis, against HIV-1 that causes AIDS and against other viruses, including those that cause severe respiratory infections in children. The latter include human respiratory syncytial virus (HRSV), human metapneumovirus (HMPV) and human parainfluenza viruses (HPIV). The vaccine studies against M. tuberculosis, HMPV, HPIV1 and, HPIV2 are in the pre-clinical stage, against HRSV a phase I clinical trial has been completed. The phase I clinical studies of SeV-based vaccination were also completed for HPIV1. They were done in adults and in 1–6-year-old children. As a result of vaccination against HPIV1, a significant boost in virus-specific neutralizing antibodies was observed. A SeV-based vaccine development against HIV-1 has reached a phase II clinical trial. In Japan intranasal Sendai virus-based SARS-CoV-2 vaccine was created and tested in a mouse model. More recent applications (2024–2025) include non-integrative gene delivery for fertility restoration in mouse models, enhanced transduction in pancreatic cancer, and temperature-sensitive platforms for CRISPR-Cas9 editing in human stem cells and viral genome engineering.
== Operations == Medpace is a full-service contract research organization that manages Phase 1 through Phase IV clinical development programs for pharmaceutical, biotechnology, and medical device companies. Its services include development-plan and protocol design, project management, regulatory affairs, clinical monitoring, data management and analysis, and post-marketing support. Its principal operating regions are North America, Europe, Latin America, and Asia Pacific.
Sources: en.wikipedia.org
== Overdose == Acute overdosage is often manifested by emesis, lethargy, ataxia, tachycardia and seizures. Plasma, serum or blood concentrations of sertraline and norsertraline, its major active metabolite, may be measured to confirm a diagnosis of poisoning in hospitalized patients or to aid in the medicolegal investigation of fatalities. As with most other SSRIs its toxicity in overdose is considered relatively low.
Trastuzumab emtansine, sold under the brand name Kadcyla, is an antibody-drug conjugate consisting of the humanized monoclonal antibody trastuzumab (Herceptin) covalently linked to the cytotoxic agent DM1. Trastuzumab alone stops growth of cancer cells by binding to the HER2 receptor, whereas trastuzumab emtansine undergoes receptor-mediated internalization into cells, is catabolized in lysosomes where DM1-containing catabolites are released and subsequently bind tubulin to cause mitotic arrest and cell death. Trastuzumab binding to HER2 prevents homodimerization or heterodimerization (HER2/HER3) of the receptor, ultimately inhibiting the activation of MAPK and PI3K/AKT cellular signalling pathways. Because the monoclonal antibody targets HER2, and HER2 is only over-expressed in cancer cells, the conjugate delivers the cytotoxic agent DM1 specifically to tumor cells. The conjugate is abbreviated T-DM1. In the EMILIA clinical trial of women with advanced HER2 positive breast cancer who were already resistant to trastuzumab alone, it improved median overall survival by 5.8 months (30.9 months vs. 25.1 months) compared to the combination of lapatinib and capecitabine. Based on that trial, the U.S. Food and Drug Administration (FDA) approved marketing on 22 February 2013. Trastuzumab emtansine was developed by Genentech, and is manufactured by Lonza.
=== Fungi === Infections by fungi are a cause of high morbidity and mortality in immunocompromised persons, such as those with HIV/AIDS, tuberculosis or receiving chemotherapy. The fungi Candida, Cryptococcus neoformans and Aspergillus fumigatus cause most of these infections and antifungal resistance occurs in all of them. Multidrug resistance in fungi is increasing because of the widespread use of antifungal drugs to treat infections in immunocompromised individuals and the use of some agricultural antifungals. Antifungal resistant disease is associated with increased mortality. Some fungi (for example, Candida krusei and fluconazole) exhibit intrinsic resistance to certain antifungal drugs or classes, whereas some species develop antifungal resistance to external pressures. Antifungal resistance is a One Health concern, driven by multiple extrinsic factors, including overuse of fungicides, clinical antifungals, environmental change and host factors. In the USA fluconazole-resistant Candida species and azole resistance in Aspergillus fumigatus have been highlighted as a growing threat. 20 species of Candida can cause candidiasis infection, the most common of which is Candida albicans. Candida yeasts normally inhabit the skin and mucous membranes without causing infection. However, overgrowth of Candida can lead to candidiasis. Some Candida species (e.g. Candida glabrata) are becoming resistant to first-line and second-line antifungal agents such as echinocandins and azoles.
== Training and certification to practice == Clinical psychologists study a generalist program in psychology plus postgraduate training and/or clinical placement and supervision. The length of training differs across the world, ranging from four years plus post-Bachelors supervised practice to a doctorate of three to six years which combines clinical placement. The practice of clinical psychology requires a license in the United States, Canada, the United Kingdom, and many other countries.
== Discontinuation of clinical development == During phase I human clinical trials for the treatment of cocaine abuse, development of JDTic was halted due to the occurrence of non-sustained ventricular tachycardia, a type of arrhythmia that can potentially be life-threatening. As a result, new KOR antagonists with more favorable drug profiles (e.g., short-acting, improved brain penetration, etc.), such as ALKS-5461 (a combination of buprenorphine and samidorphan) and CERC-501 (formerly LY-2456302), are being developed instead. The discontinuation of the clinical development of JDTic is detailed in the following important literature quote:
Sources: en.wikipedia.org
Each freeze-thaw cycle can degrade a fraction of the peptide and promote aggregation. Dividing a stock solution into single-use volumes removes repeated cycling as a variable. It also limits the time a thawed solution spends at room temperature.
A high main-peak percentage says little about identity, counter-ion content, or residual solvents. It also does not distinguish an isomer or a closely eluting analog. Mass confirmation and the accompanying documentation cover those gaps.
Salt form changes mass, solubility, and hygroscopicity, and acetate and trifluoroacetate salts behave differently in solution. Storage guidance still centers on -20 °C for powder and lower temperatures for solutions. The certificate should state which salt is present.
不是。Semax 是完全人工合成的七肽，自然界中没有对应的已知肽段。它的设计灵感来自促肾上腺皮质激素片段 ACTH(4-10)，但序列经过了替换和延长。