���发背景与监管地位 — Common Mistakes

By Editorial Desk · published 2026-04-11 · last reviewed 2026-05-29 · News

If you have been reading about Methionine oxidation 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 2026-05-29. Numbers and descriptions here follow the published literature rather than marketing material.

研发背景与监管地位

Semax 是人工设计的七肽，序列为 Met-Glu-His-Phe-Pro-Gly-Pro，骨架取自促肾上腺皮质激素片段 ACTH(4-10)。它于二十世纪八十年代在苏联的分子遗传学研究机构内合成。设计目标是保留该片段与注意力和记忆相关的活性，同时剔除促皮质激素释放等内分泌作用。此后俄罗斯将其登记为药品并进入临床使用。

当时的短肽研究普遍关注能否穿越血脑屏障、在低剂量下产生中枢效应，Semax 属于这一路线。鼻内给药是其主要使用方式，俄语文献报道的适应症涵盖缺血性卒中、短暂性脑缺血发作、认知功能减退以及视神经病变。这些研究大多发表在当地期刊上，样本规模与终点设置同西方试验惯例存在差异，国际同行对其临床证据的强度看法不一。

Mechanism and Research Context

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.

Semax at a glance

Background and Development

Semax is a synthetic heptapeptide developed in the Soviet Union during the 1980s by researchers at the Institute of Molecular Genetics in Moscow. It was designed as a truncated analog of adrenocorticotropic hormone, retaining only the fragment spanning residues four through ten. Investigators sought a peptide that would preserve the cognitive effects associated with ACTH while eliminating the hormonal stimulation of the adrenal cortex. The compound entered clinical use in Russia during the following decade.

Russian regulatory authorities approved the peptide for nasal administration, and it remains listed in the national pharmacopoeia under several trade names. Documented indications include acute ischemic stroke, transient ischemic attacks, traumatic brain injury, and certain ophthalmological and neurological conditions. Physicians also prescribe it for cognitive complaints in older patients, although the evidence base for that use is thinner. Outside Russia and a few neighboring states, the substance is not an approved medicine and is sold instead as a research chemical.

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Analytical Testing And Storage

Identity and purity of semax are established with reversed-phase high-performance liquid chromatography coupled to ultraviolet detection, usually at 214 nanometres. Mass spectrometry, most often electrospray ionisation in positive mode, confirms the molecular mass and reveals truncated sequences. Amino acid analysis and peptide mapping after enzymatic digestion provide additional structural confirmation. Laboratories typically report purity as the percentage area of the main peak, a figure that does not capture isomeric or oxidised variants unless the method resolves them.

The peptide is prone to several degradation pathways. Oxidation of the methionine residue produces a sulfoxide that elutes close to the parent peak in many chromatographic systems. Hydrolysis of peptide bonds and deamidation of susceptible residues in related sequences also reduce purity over time. Lyophilised material kept dry at minus twenty degrees Celsius and shielded from light is the most stable form commonly described in laboratory practice.

Semax Origin and Molecular Structure

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.

Analytical Methods and Stability Profile

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.

Further detail

The (3R, 6R, 7R) series 2, 3 showed very good levels of selectivity relative to the vasopressin receptors. However, although all the (3R, 6R, 7R) isomers of the monosubstituted aryl 2,5-DKPs with wide range of different functionality had similarly high levels of potency, they all had low bioavailability in the rat. Optimization of the pharmacokinetic (PK) profile of this template was achieved by property-based design using an estimated of human oral absorption (EHOA) which focused the SAR on 2,5-DKPs with small exocyclic aromatic rings combined with small amides. This resulted in the 2’,4’-difluoro dimethylamide 3 which achieved good oral bioavailability in the rat (53%) and dog (51%) whilst retaining good oxytocin antagonist potency (Ki= 0.63nM) and >1000 fold selectivity relative to the human vasopressin V1A, V2, V1B receptors. The introduction of polar heterocycles to improve the solubility and human cytochrome P450 (Cyp450) enzyme profile of 3 using intrinsic clearance in microsomes to drive the improvements in the later’s pharmacokinetic profile lead to the 2’,6’-dimethyl-3’-pyridyl morpholine amide Epelsiban.

== See also == History of radar Acoustic mirror Battle of the Beams British military history of World War II Chain Home Low Civilian Technical Corps Ground-controlled interception ROTOR RAF Air Defence Radar Museum Castles in the Sky (film)

Solanine is a glycoalkaloid poison created by various plants in the genus Solanum, such as the potato plant. When the plant's stem, tubers, or leaves are exposed to sunlight, it stimulates the biosynthesis of solanine and other glycoalkaloids as a defense mechanism so it is not eaten. It is therefore considered to be a natural pesticide. Though the structures of the intermediates in this biosynthetic pathway are shown, many of the specific enzymes involved in these chemical processes are not known. However, it is known that in the biosynthesis of solanine, cholesterol is first converted into the steroidal alkaloid solanidine. This is accomplished through a series of hydroxylation, transamination, oxidation, cyclization, dehydration, and reduction reactions. Specifically, solanidine formation involves sequential hydroxylation, transamination, and cyclization reactions.The solanidine is then converted into solanine through a series of glycosylation reactions catalyzed by specific glycosyltransferases. Plants like the potato and tomato constantly synthesize low levels of glycoalkaloids like solanine. However, under stress, such as the presence of a pest or herbivore, they increase the synthesis of compounds like solanine as a natural chemical defense. This rapid increase in glycoalkaloid concentration gives the potatoes a bitter taste, and stressful stimuli like light also stimulate photosynthesis and the accumulation of chlorophyll. As a result, the potatoes turn green, and are thus unattractive to pests.

Sources: en.wikipedia.org

Supporting material

== Quantification == Today, HPLC with UV-detection is the reference-method (e.g. DIN 10751–3). Classic methods for the quantification of HMF in food use photometry. The method according to White is a differential UV-photometry with and without sodium bisulfite-reduction of HMF. Winkler photometric method is a colour-reaction using p-toluidine and barbituric acid (DIN 10751–1). Photometric test may be unspecific as they may detect also related substances, leading to higher results than HPLC-measurements. Test-kits for rapid analyses are also available (e.g. Reflectoquant HMF, Merck KGaA).

Local botulinum toxin A injections for cosmetic purposes have on occasion caused weaknesses in distant muscles, symptoms resembling ocular or generalized myasthenia gravis in individuals with subclinical myasthenia gravis, and exacerbations of previously controlled myasthenia gravis. Botulinum toxin A has also been used to treat spasmodic torticollis (i.e., involuntarily neck turning), blepharospasm (involuntary contraction of the eye lids), and other uncontrolled facial muscle spasms in people with myasthenia gravis without side effects or with only short-lived dysphagia or diplopia. Magnesium: Magnesium is a chemical element that blocks skeletal muscle contraction by inhibiting the release or acetylcholine at the neuromuscular junction and also by lowering the sensitivity of these muscles to acetylcholine. Respiratory failure has occurred after systemic use of magnesium (mainly in the form of intravenous magnesium sulfate injections) for pre-eclampsia and after magnesium replacement during the course of a hospitalization in people with underlying myasthenia gravis. Local anesthetics: Local anesthetics cause absence of pain and all other sensations in a specific body part without loss of consciousness. There are two broad classes of these anesthetics: esters (i.e., procaine, cocaine, tetracaine benzocaine, and chloroprocaine) and amides (i.e. , lidocaine, bupivacaine, etidocaine, levobupivacaine, mepivacaine, prilocaine, and ropivacaine).

1993/423) Designation of Institutions of Higher Education (Scotland) Amendment Order 1993 (S.I. 1993/424) High Court of Justiciary Fees Amendment Order 1993 (S.I. 1993/426) Court of Session etc. Fees Amendment Order 1993 (S.I. 1993/427) Sheriff Court Fees Amendment Order 1993 (S.I. 1993/428) Seeds (Fees) (Amendment) Regulations 1993 (S.I. 1993/429) Plant Breeders' Rights (Fees) (Amendment) Regulations 1993 (S.I. 1993/430) Education (PCFC and UFC Staff) Order 1993 (S.I. 1993/434) Education (Designated Institutions in Further Education) Order 1993 (S.I. 1993/435) Cheshire, Greater Manchester, Lancashire and Merseyside (County and District Boundaries) Order 1993 (S.I. 1993/436) Hereford and Worcester, Warwickshire and West Midlands (County and Metropolitan Borough Boundaries) Order 1993 (S.I. 1993/437) Bankruptcy (Scotland) Act 1993 Commencement and Savings Order 1993 (S.I. 1993/438) Bankruptcy (Scotland) Amendment Regulations 1993 (S.I. 1993/439) Essex, Greater London and Hertfordshire (County and London Borough Boundaries) Order 1993 (S.I. 1993/441) Derbyshire and Nottinghamshire (County Boundaries) Order 1993 (S.I. 1993/444) Environmental Protection (Waste Recycling Payments) (Amendment) Regulations 1993 (S.I. 1993/445) National Rivers Authority (Severn-Trent Region) (Reconstitution of the South Gloucestershire Internal Drainage Board) Order 1992 S.I. 1993/451) Alteration of Boundaries of the Beverley and North Holderness Internal Drainage District Order 1993 (S.I. 1993/452) Reconstitution of the South Holland Internal Drainage Board Order 1993 (S.I.

Sources: en.wikipedia.org

Notes from published material

==== MeSH D06.472.931 – thyroid hormones ==== MeSH D06.472.931.103 – dextrothyroxine MeSH D06.472.931.208 – diiodotyrosine MeSH D06.472.931.388 – monoiodotyrosine MeSH D06.472.931.669 – thyroid gland, desiccated MeSH D06.472.931.740 – thyronines MeSH D06.472.931.740.180 – diiodothyronines MeSH D06.472.931.740.385 – triiodothyronine MeSH D06.472.931.740.590 – triiodothyronine, reverse MeSH D06.472.931.812 – thyroxine

== Research == Lebrikizumab is under investigation as an immunosuppressive medication for the treatment of asthma that cannot be adequately controlled with inhalable glucocorticoids. It was created by Tanox under the code name TNX-650, and a phase I clinical trial for refractory Hodgkin's lymphoma had been performed when Genentech acquired Tanox in 2007. It has successfully completed a phase II clinical trial for the treatment of asthma.

== Clinical significance == The epithelium of the glans penis consists of mucosal tissue. Birley et al. report that excessive washing with soap may dry the mucous membrane which covers the glans penis and cause non-specific dermatitis. The condition is described as an inflammation of the skin, often caused by an irritating substance or a contact allergy. Sensitivity to chemicals in certain products can cause an allergic reaction, including irritation, itching and rash. Inflammation of the glans penis is known as balanitis. It is a treatable condition that occurs in about 3–11% of males (up to 35% of diabetic males). Edwards reported that it is generally more common in males who have poor hygiene habits or have not been circumcised. It has many causes, including irritation or infection with a wide variety of pathogens. Symptoms of balanitis may appear suddenly or develop gradually. They might include pain, irritation, redness or red patches on the glans penis. Careful identification of the cause with the aid of patient history, physical examination, swabs and cultures, and biopsy are essential in order to determine the proper treatment. The meatus (opening) of the urethra located at the tip of the glans might become subject to meatal stenosis, a condition mostly seen as a late complication of circumcision. It occurs in about 2–20% of circumcised boys and it is rarely seen in uncircumcised men. It is characterized by a narrowing of the meatus, which might cause sudden or often urges to urinate and burning during the process.

Sources: en.wikipedia.org

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