If you have been reading about counter-ion 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.
Last reviewed on 2025-11-01. Where a claim depends on a specific study, the study is described rather than over-claimed.
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.
Published research on this peptide originates mainly from Russian laboratories, and the wider international literature is comparatively thin. Studies have used rodent models of stroke, hypoxia, and memory tasks, with a smaller number of human trials reported. Reported outcomes include changes in attention and memory measures, along with effects on neurotrophic factor expression in some experiments. Small sample sizes, inconsistent dosing protocols, and limited independent replication are widely noted limitations, so the strength of the clinical evidence remains an open question.
Semax is a synthetic heptapeptide whose sequence is Met-Glu-His-Phe-Pro-Gly-Pro. The first four residues correspond to the ACTH(4-10) fragment, while the terminal Pro-Gly-Pro extension was added to improve metabolic stability. Its molecular formula is C37H51N9O10S and its monoisotopic mass is approximately 813.9 Da. The compound is classified as a peptide research chemical and as a registered pharmaceutical product in Russia, but it does not hold marketing approval in the European Union or the United States. Naming conventions vary across supplier catalogs.
Development of the compound took place in the Soviet Union during the 1980s, largely through peptide research groups affiliated with the Shemyakin-Ovchinnikov Institute and Moscow State University. Investigators screened fragments of adrenocorticotropic hormone for activity on the central nervous system while attempting to separate cognitive effects from hormonal ones. The shortened sequence was selected because it retained behavioral activity in animal models without stimulating corticosteroid release. Early publications described the molecule as an ACTH(4-10) analog.
| Property | Value | Notes |
|---|---|---|
| Typical purity | 95% or higher | By reversed-phase HPLC area |
| Identity method | Electrospray mass spectrometry | Confirms molecular mass |
| Purity method | Reversed-phase HPLC | Detection near 214 nm |
| Primary degradation | Methionine oxidation | Sulfoxide product, +16 Da |
| Solution storage | 2-8 °C, short term | Aliquot to avoid freeze-thaw |
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.
Development is attributed to researchers at the Institute of Molecular Genetics in Moscow during the early 1980s, building on earlier Soviet work with ACTH fragments. Russian regulatory approval followed for intranasal use, and the compound has remained commercially available there for decades. Most published human data originate from Russian and, later, some Eastern European clinical reports, which are not always accessible in English translation. Outside that region the material is generally handled as a research chemical rather than a licensed medicine.
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.
is known as the Lamb vector. For the special case of an incompressible flow, the pressure constrains the flow so that the volume of fluid elements is constant: isochoric flow resulting in a solenoidal velocity field with
Pan frying (sauté) on stove top heat: 120 °C (248 °F) Deep frying: 160–180 °C (320–356 °F) Oven baking: Average of 180 °C (356 °F) Smoke point decreases at a different pace in different oils. Considerably above the temperature of the smoke point is the flash point, the point at which the vapours from the oil can ignite in air, given an ignition source. The following table presents smoke points of various fats and oils.
Amine groups are found throughout an antibody and are used as a target due to their easy steric accessibility and modification. An overview of this reaction is found in Figure 2. Most often amine groups found on lysine are covalently bonded to carboxyl groups of glutamic and aspartic acid on formed liposomes using certain agents. A two step process is utilized where the first step uses 1-ethyl-3-[3-dimethylaminopropyl] carbodiimide to create an amine reactive product from the carboxyl group. This product is a target for a nucleophilic attack by the amine but it hydrolyzes quickly, so EDC is added to stabilize it. As seen in the Figure 2, the intermediate can lead to the desired stable amide bond by chance or the recreation of a carboxyl group. To create more of the desired carboxyl-amine bond, N-hydroxysulfosuccinimide (sulfo-NHS) is added to form another intermediate that is an NHS ester. The second step to this reaction is for the antibodies to use the N-terminus of the lipid to covalently conjugate by creating an amide bond via displacement of sulfo-NHS groups. This leads to the final product of an antibody conjugated to a liposome to create an immunoliposome. This process is highly efficient and effective while maintaining the biological activity of the antibody.
Brazzein is a sweet-tasting protein that occurs naturally in oubli (Pentadiplandra brazzeana), a fruit native to the Atlantic coastal areas of Central Africa. Brazzein was named in 1994 by scientists at the University of Wisconsin–Madison. It is roughly 500 to 2000 times sweeter than sucrose. Brazzein is found in the extracellular region of oubli fruit, in the pulp tissue surrounding the seeds. It was first discovered and isolated in 1989 by Wel et al. under the name of pentadin. The corresponding author of both these publications has later opined that pentadin and brazzein are two different names for the same protein. Even though pentadin is the earlier proposed name, brazzein is the more commonly used name after more extensive characterisation of the sweet protein. Like other sweet proteins discovered in plants, such as monellin and thaumatin, brazzein is extremely sweet compared to commonly used sweeteners. The fruit tastes sweet to humans, monkeys, and bonobos, but gorillas have mutations in their sweetness receptors so that they do not find brazzein sweet, and they are not known to eat the fruit.
The patagium is the wing membrane, which reaches from the arm and finger bones to the side of the body and the hindlimbs. The extent to which the tail of a bat is attached to a patagium can vary by species, with some having completely free tails or even no tails. For bat embryos, only the hindfeet experience apoptosis (programmed cell death), while the forefeet retain webbing between the fingers that become the wing membranes. These structures include connective tissue, elastic fibres, nerves, muscles, and blood vessels. The muscles keep the membrane taut as the animal flies. While the skin on the body of the bat is covered in hair and sweat glands with an epidermis, a dermis, and a fatty subcutaneous layer, the patagium is an extremely thin double layer of epidermis separated by a connective tissue centre rich with collagen and elastic fibres. The surface of the wings is equipped with touch-sensitive receptors on small bumps called Merkel cells. Each bump has a tiny hair in the centre, allowing the bat to detect and adapt to changing airflow; the primary use is to judge the most efficient speed at which to fly, and possibly also to avoid stalls. Insectivorous bats may also use tactile hairs when manoeuvring to capture flying insects. While delicate, the membranes can heal quickly and regrow when torn. Photoluminescence has been reported in at least six North American species based on 60 museum specimens. The wings, uropatagium (around the tail), and hind limbs of these bats glowed green when exposed to UV light.
Sources: en.wikipedia.org
=== Premenstrual dysphoric disorder === Fluoxetine is used to treat premenstrual dysphoric disorder, a condition where individuals have affective and somatic symptoms monthly during the luteal phase of menstruation. Taking fluoxetine 20 mg/d can be effective in treating PMDD, though doses of 10 mg/d have also been prescribed effectively.
Carruthers also studied and reported in 1992 the use of botulinum toxin type-A as a cosmetic treatment.[78] They conducted a study of participants whose only concern was their glabellar forehead wrinkle or furrow. Study participants were otherwise normal. Sixteen of seventeen participants available for follow-up demonstrated a cosmetic improvement. This study was reported at a meeting in 1991. The study for the treatment of glabellar frown lines was published in 1992. This result was subsequently confirmed by other groups (Brin, and the Columbia University group under Monte Keen). The FDA announced regulatory approval of botulinum toxin type A (Botox Cosmetic) to temporarily improve the appearance of moderate-to-severe frown lines between the eyebrows (glabellar lines) in 2002 after extensive clinical trials. Well before this, the cosmetic use of botulinum toxin type A became widespread. The results of Botox Cosmetic can last up to four months and may vary with each patient. The US Food and Drug Administration (FDA) approved an alternative product-safety testing method in response to increasing public concern that LD50 testing was required for each batch sold in the market. Botulinum toxin type-A has also been used in the treatment of gummy smiles; the material is injected into the hyperactive muscles of upper lip, which causes a reduction in the upward movement of lip thus resulting in a smile with a less exposure of gingiva.
=== Murder cases === 1965: Tan Kheng Ann (alias Robert Black) and 17 others who led the Pulau Senang prison riot. They were found guilty of the murders of a prison officer and his three assistants, and hanged on 29 October 1965. 1968: Usman bin Haji Muhammad Ali and Harun Thohir, two Indonesian marines who carried out the 1965 MacDonald House bombing which killed three people (when Singapore was still a part of Malaysia). They were convicted of murder and hanged on 17 October 1968. 1970: Lim Heng Soon and Low Ngah Ngah, the two Singaporeans found guilty of stabbing and killing police detective D. Munusamy in February 1968. Both men were sentenced to hang on 30 November 1968, and after losing their appeals to the Singaporean Court of Appeal and Privy Council in London between November 1969 and March 1970, the duo were eventually hanged. 1972: Liew Kim Siong and Kee Ah Tee, the two Singaporean youths hanged in 1972 for the 1969 Upper Bukit Timah factory murders, where two Hongkongers were stabbed to death during the duo's robbery bid 1973: Osman bin Ali, an Indonesian-born Singaporean and gardener who was found guilty of murdering a cook and an amah at a bungalow in Leedon Park. He was sentenced to death in September 1971, and hanged on 27 July 1973 after losing his appeal. 1973: Mimi Wong Weng Siu and her husband Sim Woh Kum, the first couple to be sentenced to death in Singapore. Both Wong and Sim were convicted of the 1970 murder of Ayako Watanabe, the wife of Wong's Japanese lover, and hanged on 27 July 1973.
== Other uses == lh (digraph), in many languages Bristol LH, a type of British bus manufactured between 1967 and 1982 Chrysler LH platform, a type of Chrysler car made from 1993 through 2004 Late Helladic, a period in the history of ancient Greece, during the Bronze Age Leasehold, or tenure, in property law Left-handed, or left hand Letterhead, a heading at the top of a sheet of letter paper Lewis Hamilton (born 1985), British racing driver
Fasedienol (INNTooltip International Nonproprietary Name; developmental code names PH94B and Aloradine), also known as 4-androstadienol or as 4,16-androstadien-3β-ol, is a pherine which is under development by VistaGen Therapeutics in a nasal spray formulation used as needed(PRN) for the acute treatment of social anxiety disorder. It is also being investigated by VistaGen Therapeutics for the treatment of generalized anxiety disorder (GAD) and post-traumatic stress disorder (PTSD). The pherine is a positional isomer of the endogenous pheromone androstadienol (5-androstadienol or 5,16-androstadien-3β-ol). Fasedienol failed to show effectiveness in phase 3 clinical trials. Fasedienol lacks affinity for steroid hormone receptors and has instead been found to directly activate isolated human vomeronasal receptor cells at nanomolar concentrations (EC50 = 200 nM). The closely related pheromone androstenol (5α-androst-16-en-3α-ol) has been found to act as a potent positive allosteric modulator of the GABAA receptor, and it has been proposed that this action may mediate its pheromone effects. It produces anxiolytic-like effects in animals. Androstadienol, androstadienone, and androstenone, all of which are also pheromones, have been found to be converted into androstenol, and as such, it may be responsible for their pheromone effects. As fasedienol is very closely related structurally to androstadienol, it might be converted into androstenol similarly and hence potentiation of the GABAA receptor could contribute to its mechanism of action.
Sources: en.wikipedia.org
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.
In solution, hydrolysis of peptide bonds and oxidation of the methionine residue are the principal concerns. Oxidation converts methionine to its sulfoxide form, shifting the mass by sixteen daltons. Both processes are slowed by cold storage and by avoiding alkaline conditions.
A certificate documents what the supplier measured on a specific lot, not how a laboratory will use the material. Independent verification of identity and purity is common practice. Acceptance criteria should be defined before a batch is ordered.
It is a synthetic peptide of seven amino acids. Its backbone corresponds to a fragment of adrenocorticotropic hormone extended at the carboxyl end. The material is distributed as a lyophilized solid for laboratory use.