Everything below concerns RP-HPLC. We keep the language plain, cite what the science says, and separate well-supported claims from open questions.
Last reviewed on 2025-10-07. Where a claim depends on a specific study, the study is described rather than over-claimed.
Native GLP-1 is degraded rapidly by dipeptidyl peptidase-4. Semaglutide resists this cleavage because alanine at position 8 is replaced by alpha-aminoisobutyric acid. A second substitution at position 34 introduces arginine, which further stabilizes the peptide. The most distinctive modification is a spacer and C18 fatty diacid attached at lysine 26, enabling strong albumin affinity. These three changes together produce a half-life measured in days rather than minutes, and the same structural logic underlies other long-acting analogs in this class.
Semaglutide is a synthetic peptide analog of glucagon-like peptide-1, a hormone released from intestinal L-cells after food intake. It contains 31 amino acids and differs from native GLP-1 through modifications that slow enzymatic breakdown. The peptide was developed to extend the short circulating half-life of endogenous GLP-1, which is measured in minutes. Researchers introduced the compound in the early 2010s. Two backbone changes and a fatty acid side chain define its structure, distinguishing it from earlier GLP-1 receptor agonists.
Large randomised trials in adults with type 2 diabetes and in adults with obesity have reported reductions in body weight and improvements in several cardiovascular risk markers. One outcome trial found a lower incidence of major adverse cardiovascular events in participants with diabetes and established cardiovascular disease. Gastrointestinal effects such as nausea and vomiting are the most frequently reported adverse events and often diminish over time. Changes in lean body mass during weight loss are an area of ongoing investigation. Effects in adolescents and in pregnancy are less well characterised, and current labelling advises against use during pregnancy.
Semaglutide is a synthetic peptide analogue of glucagon-like peptide-1, a gut hormone released after nutrient intake. The molecule contains 31 amino acid residues and differs from the native sequence at several positions. A non-natural residue at position eight resists the enzyme that normally truncates the hormone, while a lysine-linked fatty diacid side chain promotes binding to serum albumin. These two modifications extend the circulating half-life from minutes to roughly one week. The peptide is produced by solid-phase synthesis followed by selective acylation, and its identity and purity are confirmed by spectrometric and chromatographic techniques.
| Property | Value | Notes |
|---|---|---|
| Molecular class | Synthetic peptide | 31 amino acids |
| Backbone modification | Aib at position 8 | Blocks DPP-4 cleavage |
| Fatty acid chain | C18 diacid | Supports albumin binding |
| Native half-life | 1 to 2 minutes | Endogenous GLP-1 |
| Analog half-life | Approximately one week | Extended by albumin binding |
Lyophilised semaglutide is generally held at -20 °C or below, protected from light and moisture. Reconstituted solutions are typically kept at 2-8 °C and used within a defined window because degradation accumulates over time. Repeated freeze-thaw cycles are discouraged, since each cycle can promote aggregation and reduce monomeric content. Room-temperature stability of the solid has been examined in some studies but remains incompletely characterised for long durations, so cold storage is the conservative default for research material.
Degradation proceeds along several parallel routes. Deamidation of asparagine and glutamine residues generates charged variants that shift retention time in chromatographic analysis. Oxidation targets methionine and can be accelerated by trace metals or dissolved oxygen. Non-covalent aggregation produces dimers, oligomers, and larger species that are difficult to reverse. Isomerisation at aspartate residues is slower but measurable under thermal stress. The distribution among these pathways depends on pH, buffer composition, ionic strength, and the presence of excipients such as sugars or surfactants.
Reverse-phase high-performance liquid chromatography with ultraviolet detection near 214 nm is the standard purity method, reported as area percent. Mass spectrometry, usually with electrospray ionisation, confirms identity and reveals covalent modifications. Size-exclusion chromatography quantifies aggregates and fragments. Peptide mapping after enzymatic digestion localises changes to specific sequence regions. Circular dichroism and infrared spectroscopy report on secondary structure, while light scattering tracks particle formation in liquid formulations. No single technique captures every quality attribute.
Reverse-phase high-performance liquid chromatography is the standard method for purity assessment, separating the peptide from truncated or oxidized variants. Mass spectrometry confirms molecular mass and detects modifications, while ultraviolet absorbance near 280 nanometers supports concentration measurement through tryptophan and tyrosine residues. Circular dichroism can indicate secondary structure, though the peptide is largely helical in solution, and ion-exchange chromatography resolves charge variants. Purity values above 95 percent are typical for research-grade material. Stability studies track degradation over time under defined conditions.
Lyophilized semaglutide is typically stored at temperatures between minus 20 and minus 80 degrees Celsius for long-term preservation. Short-term storage at 2 to 8 degrees Celsius is common for working aliquots. Repeated freeze-thaw cycles can degrade the peptide and are usually avoided. The molecule is hygroscopic in its solid form, so containers should remain sealed with desiccant. Solutions are less stable than powders and are generally prepared fresh. Light exposure is limited because aromatic residues can undergo photo-oxidation.
Routine characterisation of the peptide relies on reversed-phase high-performance liquid chromatography, often paired with ultraviolet detection near 214 nanometres. Related substances such as deamidated, oxidised, and truncated sequences elute at characteristic positions and are quantified by area percentage. Electrospray ionisation mass spectrometry confirms the molecular mass and can resolve some closely related variants. Peptide mapping after enzymatic digestion provides sequence-level verification and is useful when a full identity profile is required. Method parameters such as column chemistry, gradient, and mobile-phase pH influence the separation and must be reported alongside results.
Material described as research-grade is not necessarily manufactured to pharmaceutical standards, and purity figures depend on the method used to obtain them. A certificate of analysis states the measured purity, the analytical technique, and the batch identifier, but the underlying data are not always included. Independent testing by a second laboratory is a common way to confirm identity and purity. Uncertainties remain about how storage history affects long-term stability, and about how well results from one laboratory transfer to another. Documentation of handling conditions supports comparison between batches.
Two structural features account for the prolonged half-life of semaglutide. A modified amino acid at position 8 resists cleavage by dipeptidyl peptidase-4, the enzyme that rapidly degrades native GLP-1. A fatty diacid side chain binds serum albumin, which limits renal clearance and protects the peptide from enzymatic breakdown. These modifications yield a plasma half-life of approximately one week in humans, allowing once-weekly administration. The relationship between plasma concentration and clinical effect varies between individuals, and sources of that variability are still being characterized.
Semaglutide is a synthetic peptide analog of glucagon-like peptide-1 (GLP-1), a hormone released from intestinal L-cells after food intake. The compound belongs to the incretin mimetic class and acts at GLP-1 receptors distributed across pancreatic, gastrointestinal, cardiovascular, and central nervous system tissues. Compared with native GLP-1, the molecule carries structural changes that extend its activity from minutes to roughly one week. It is studied for glycemic control in type 2 diabetes and for weight management, and its effects on cardiovascular and other outcomes remain active research areas.
However, all three co-authors of the bill issued a statement that instead, the bill "[narrowed] existing broad presidential authority to take over telecommunications networks". In August 2010, the U.S. for the first time warned publicly about the Chinese military's use of civilian computer experts in clandestine cyber attacks aimed at American companies and government agencies. The Pentagon also pointed to an alleged China-based computer spying network dubbed GhostNet which was revealed in a 2009 research report. On 6 October 2011, it was announced that Creech AFB's drone and Predator fleet's command and control data stream had been keylogged, resisting all attempts to reverse the exploit, for the past two weeks. The Air Force issued a statement that the virus had "posed no threat to our operational mission". On 21 November 2011, it was widely reported in the U.S. media that a hacker had destroyed a water pump at the Curran-Gardner Township Public Water District in Illinois. However, it later turned out that this information was not only false, but had been inappropriately leaked from the Illinois Statewide Terrorism and Intelligence Center. In June 2012 the New York Times reported that president Obama had ordered the cyber attack on Iranian nuclear enrichment facilities. In August 2012, USA Today reported that the US conducted cyberattacks for tactical advantage in Afghanistan.
=== Ch–Che === Michael Chamberlin (1937–2025). American molecular biologist at UC Berkeley, with research focussed on gene expression in both prokaryotes and eukaryotes. Member Natl. Acad. Sci. USA. Britton Chance (1913–2010). American biochemist at the University of Pennsylvania. He studied enzyme structure and function, and invented the stopped-flow spectrophotometer for studying fast reactions. Member Natl. Acad. Sci. USA. Christopher Chang (b. 1974). American bioinorganic chemist at UC Berkeley. His research includes molecular imaging sensors for the study of redox biology. Jean-Pierre Changeux (b. 1936). French biochemist and neuroscientist at the Collège de France and Institut Pasteur. Originator of the allosteric model of cooperativity, but now known mainly for work in neuroscience. Emmett Chappelle (1925–2019). American biochemist at NASA, known for using bioluminescence to develop a method of detecting ATP. Erwin Chargaff (1905–2002). Austrian-American biochemist at Columbia, known for Chargaff's rules, according to the first of which the number of guanine units in DNA is equal to the number of cytosine units, and the number of adenine units is equal to the number of thymine units. Emmanuelle Charpentier (b. 1968). French microbiologist, geneticist and biochemist. She (with Jennifer Doudna) discovered genome editing with CRISPR. Nobel Prize for Chemistry in 2020. Foreign Associate Natl. Acad. Sci. USA Martha Chase (1927–2003).
=== Metric ounce === A metric ounce is an approximation of the imperial ounce, US dry ounce, or US fluid ounce. These three customary units vary. However, the metric ounce is usually taken as 25 or 30 ml (0.88 or 1.06 imp fl oz; 0.85 or 1.01 US fl oz) when volume is being measured, or in grams when mass is being measured. The US Food and Drug Administration (FDA) defines the "food labeling ounce" as 30.0 ml (1.06 imp fl oz; 1.01 US fl oz), slightly larger than the 29.6 ml (1.04 imp fl oz; 1.00 US fl oz) fluid ounce. Several Dutch units of measurement have been replaced with informal metric equivalents, including the ons or ounce. It originally meant 1⁄16 of a pound, or a little over 30 g (1.1 oz) depending on which definition of the pound was used, but was redefined as 100 g (3.5 oz) when the country metricated.
==== Potential path: sludge to food ==== PFOA and PFOS were detected in "very high" (low parts per million) levels in agricultural fields for grazing beef cattle and crops around Decatur, Alabama. The approximately 5000 acres of land were fertilized with "treated municipal sewage sludge, or biosolids". PFOA was also detected in fodder grass grown in these soils and the blood of the cattle feeding on this grass. The water treatment plant received process wastewater from a nearby perfluorochemical manufacturing plant. 3M says they managed their own wastes, but Daikin America "discharged process wastewater to the municipal waste treatment plant". If traced to meat, it would be the first time perfluorochemicals were traced from sludge to food. However, the USDA reported—with a detection limits of 20 parts per billion—non-detectable levels for both PFOA and PFOS in cattle muscle tissue.
In March 2025, Moore announced a compromise spending plan negotiated with legislative leaders that would cut state spending by $2.5 billion, raise more than $1 billion in new taxes, and create a projected $350 million budget surplus for the 2027 fiscal year. The budget proposal would impose a 3% sales tax on data and IT services and a 2% capital gains tax, increase taxes on cannabis sales and sports betting, and includes "federal government spending triggers" that would activate in response to federal budget cuts. It also excludes several proposals from Moore's initial budget proposal, including a 75-cent delivery fee, a corporate tax cut, and the elimination of the inheritance tax. After President Donald Trump enacted a 25% tariff on car imports, the Senate opted to scale back a proposed increase to the state's vehicle excise tax and added a $5 per tire fee to pay for state transportation projects. Moore signed the compromise spending plan into law in May 2025. In November 2025, after state analysts released a report showing that the state would face a $1.5 billion deficit in fiscal year 2027 as a result of tax changes from the One Big Beautiful Bill Act and increased costs for social programs, Moore ruled out any tax increases during the 2026 legislative session.
Sources: en.wikipedia.org
=== Wound healing === Myofibroblasts can contract by using smooth muscle type actin-myosin complex, rich in a form of actin called alpha-smooth muscle actin. These cells are then capable of speeding wound repair by contracting the edges of the wound. Early work on wound healing showed that granulation tissue taken from a wound could contract in vitro (or in an organ bath) in a similar fashion to smooth muscle, when exposed to substances that cause smooth muscle to contract, such as adrenaline or angiotensin. More recently it has been shown that fibroblasts can transform into myofibroblasts with photobiomodulation. After healing is complete, these cells are lost through apoptosis and it has been suggested that in several fibrotic diseases (for example liver cirrhosis, kidney fibrosis, retroperitoneal fibrosis) that this mechanism fails to work, leading to persistence of the myofibroblasts, and consequently expansion of the extracellular matrix (fibrosis) with contraction. Similarly, in wounds that fail to resolve and become keloids or hypertrophic scars, myofibroblasts may persist, rather than disappearing by apoptosis.
Delta cells (δ-cells or D cells) are somatostatin-producing cells. They can be found in the stomach, intestine and the pancreatic islets. Delta cells comprise ca 5% of the cells in the islets but may interact with many more islet cells than suggested by their low numbers. In rodents, delta-cells are located in the periphery of the islets; in humans the islet architecture is generally less organized and delta-cells are frequently observed inside the islets as well. In both species, the peptide hormone Urocortin III (Ucn3) is a major local signal that is released from beta cells (and alpha cells in primates) to induce the local secretion of somatostatin. It has also been suggested that somatostatin may be implicated in insulin-induced hypoglycaemia through a mechanism involving SGLT-2 receptors. Ghrelin can also strongly stimulate somatostatin secretion, thus indirectly inhibiting insulin release. Viewed under an electron microscope, delta-cells can be identified as cells with smaller and slightly more compact granules than beta cells. The δ-cells in the stomach contain CCKBR (which respond to gastrin) and M3 receptors (which respond to Ach). Respectively, these receptors will increase somatostatin output and decrease somatostatin output from the δ-cells. VIP, vasoactive intestinal peptide, acts positively on δ-cells resulting in more somatostatin being released.
Corrective lenses: Orange or rose-tinted lenses help with the sensitivity from bright lights. The patients may have to adapt to reading in Braille, use adaptive equipment, mobility aids, such as canes and guide dogs, and other assistive technology can help individuals with AS maximize their skills and thrive. Hearing aids: the battery-operated devices are available in three styles: behind the ear, in the ear and inside the ear canal. Behind the ear aims for mild-to-profound hearing loss. In the ear aims for mild to severe hearing loss. Lastly, the canal device is aimed for mild to moderately severe hearing loss. Patients that have severe hearing loss may benefit from a cochlear implant. Pharmacological Intervention: Many symptoms, such as Type II diabetes, obesity, and more related to AS can be managed with pharmacological support. See below medication section. Diet: an appropriate and healthy diet is necessary for individuals with Alström syndrome because it could potentially decreases chances of obesity or diabetes. Physical Activity: exercising reduces chances of being obese and helping control blood sugar levels.
Treatments are patient-specific and depend on the symptoms that present with the disorder, as well as the progression of the condition. Improvements to the patient's life may be accomplished through the management of symptoms or slowing of the rate of demyelination. Treatment can include medication, lifestyle changes (i.e. smoking cessation, increased rest, and dietary changes), counselling, relaxation, physical exercise, patient education, and in some cases, deep brain thalamic stimulation (to ameliorate tremors).
Sources: en.wikipedia.org
== Epidemiology == Kwashiorkor is rare in high-income countries. It is mostly observed in low-income and middle-income nations and regions such as Southeast Asia, Central America, Congo, Ethiopia, Puerto Rico, Jamaica, South Africa, and Uganda, where poverty is prominent. Occurrences of severe malnutrition also tend to trend higher under conditions of food insecurity, higher prevalence of infectious diseases, lack of access to appropriate care, and poor living situations with inadequate sanitation. Communities experiencing famine are affected the most, especially during the rainy season. Prevalence varies, but it affects children of either sex commonly under five years old. "Globally, kwashiorkor indirected accounted for 53% of deaths among children under five between 2000 and 2003 when associated with other common childhood diseases like acute respiratory infections, malaria, measles, HIV/AIDS and other causes of perinatal deaths." When compared to marasmus in developing countries, kwashiorkor typically has a lower prevalence, "0.2%-1.6% for kwashiorkor and 1.2%-6.8% for marasmus." Factors such as "diet, geographical locations, climate, and aflatoxin exposure" have been invoked as potential causes for observed differences in the prevalence of kwashiorkor and marasmus. In general, in areas where Severe Acute Malnutrition (SAM) is prevalent, marasmus is more often the dominant SAM condition. However, in certain areas, kwashiorkor may be more common than marasmus.
Benzodiazepines can be useful for short-term treatment of insomnia. Their use beyond 2 to 4 weeks is not recommended due to the risk of dependence. It is preferred that benzodiazepines be taken intermittently and at the lowest effective dose. They improve sleep-related problems by shortening the time spent in bed before falling asleep, prolonging sleep time, and reducing wakefulness. Like alcohol, benzodiazepines are commonly used to treat insomnia in the short-term (both prescribed and self-medicated), but worsen sleep in the long-term. While benzodiazepines can put people to sleep (i.e., inhibit NREM stage 1 and 2 sleep), while asleep, the drugs disrupt sleep architecture by decreasing sleep time, delaying time to REM sleep, and decreasing deep slow-wave sleep (the most restorative part of sleep for both energy and mood). Other drawbacks of hypnotics, including benzodiazepines, are possible tolerance to their effects, rebound insomnia, and reduced slow-wave sleep and a withdrawal period typified by rebound insomnia and a prolonged period of anxiety and agitation. The list of benzodiazepines approved for the treatment of insomnia is similar among most countries, but which benzodiazepines are officially designated as first-line hypnotics prescribed for the treatment of insomnia can vary distinctly between countries. Longer-acting benzodiazepines, such as nitrazepam and diazepam, have residual effects that may persist into the next day and are, in general, not recommended.
electric sector without an initial drift length followed by a 60° magnetic sector with the same direction of curvature. Sometimes called a "Bainbridge mass spectrometer," this configuration is often used to determine isotopic masses. A beam of positive particles is produced from the isotope under study. The beam is subject to the combined action of perpendicular electric and magnetic fields. Since the forces due to these two fields are equal and opposite when the particles have a velocity given by
In the last decades, the growing demand from the consumers and governments for more sustainable and eco-friendly packaging design has driven the food industry to redesign and propose alternative packaging solutions. However, in designing a brand new packaging system, several variables need to be taken in consideration. As shown in the optimum packaging design chart, an ideal packaging design should only use the right amount of the appropriate materials to provide the desired performance for a specific product. Food packaging is often necessary, or even essential, for protecting food, keeping it safe, and thus preventing substantial food losses. However, food packaging today is strongly associated with both environmental risks and health risks for consumers. To help packaging professionals address this challenge, a Responsible food packaging platform (FitNESS Food Packaging) was created in 2017 by 11 European partners, to provide both general and in-depth training courses on the design of responsible food packaging. Developed with funding from the European Union Erasmus+ programme, this platform includes learning to optimise many sometimes contradictory criteria across all aspects of food packaging, from its production and use, through to its reuse, recycling, and disposal.
According to a study published in 2017, the odds of contracting CJD for patients in Japan who received a Lyodura graft was at least 1 in 877 (~0.1%). In 2004, five Australian patients had been diagnosed with Creutzfeldt–Jakob disease after receiving Lyodura grafts. Due to the long latent period of Creutzfeldt–Jakob disease, epidemiologists remain uncertain how many people will be affected by the disease. B.Braun Melsungen and several other entities agreed to compensate the families of Japanese CJD victims for more than $600,000 each. An award-winning documentary was produced on the subject. The Canadian Broadcasting Corporation's The Fifth Estate segment, "Deadly Harvest", dealt with the product's history, sale in Canada, and health effects worldwide. The product has since been banned for use in Canada.
Sources: en.wikipedia.org
It is a synthetic analog of GLP-1 produced through medicinal chemistry to resist enzymatic degradation. The design goal was longer circulation than the native hormone.
A fatty acid side chain attaches the peptide to serum albumin, which shields it from kidney filtration and protease activity. This interaction is the main reason its circulation time is extended.
No. The native hormone is GLP-1, and semaglutide is an engineered variant with three deliberate structural alterations. It does not appear in unmodified biological sources.
Native GLP-1 is degraded within minutes by dipeptidyl peptidase-4 and neutral endopeptidases. Semaglutide carries a non-natural amino acid at position eight that blocks that cleavage, and a fatty diacid side chain that binds albumin. The result is a much longer duration of action than the native hormone.