Everything below concerns fatty diacid. We keep the language plain, cite what the science says, and separate well-supported claims from open questions.
Updated 2026-03-30. Numbers and descriptions here follow the published literature rather than marketing material.
Three structural changes define the molecule. At position 8 an alpha-aminoisobutyric acid residue replaces alanine, which blocks dipeptidyl peptidase-4 cleavage. At position 34 arginine replaces lysine, and at position 26 a lysine carries a C18 fatty diacid attached through a short linker. The fatty chain binds serum albumin, and this albumin association reduces renal filtration and enzymatic attack. The unchanged backbone retains the receptor contacts that produce signalling. The free base has the formula C187H291N45O59 and a molecular weight near 4114 daltons.
Receptor activation follows the canonical Gs pathway: binding increases intracellular cyclic AMP, which promotes protein kinase A activity. In pancreatic beta cells this amplifies glucose-dependent insulin release, so secretion rises when blood glucose is high and changes little when it is low. The same signalling suppresses glucagon release from alpha cells and slows gastric emptying. Receptors in the hypothalamus and brainstem are thought to contribute to reduced appetite and lower energy intake. Which of these effects dominates clinical outcomes remains an area of active study.
Semaglutide is a synthetic peptide analogue of glucagon-like peptide-1, a gut hormone released by intestinal L cells after food intake. The natural hormone acts on pancreatic and central receptors but is degraded within minutes by dipeptidyl peptidase-4 and other peptidases. Semaglutide belongs to the class of long-acting GLP-1 receptor agonists, a group distinguished by structural changes that slow breakdown and extend circulation time. Its development followed earlier short-acting analogues and reflects a general strategy in peptide drug design: preserve receptor activity while blocking proteolytic clearance.
Handling guidance for research quantities calls for single-use aliquots, an inert atmosphere where practical, and avoidance of repeated freeze-thaw cycles that accelerate aggregation. Certificates of analysis typically report purity by peak area, water content, counter-ion identity, and residual solvent levels. In the scientific literature the compound is usually described by its full amino acid sequence, its registry number, or its structural class rather than by any proprietary label. Reporting standards vary between journals, and reviewers increasingly request raw chromatograms alongside tabulated purity figures. Whether current purity thresholds are adequate for every experimental context is debated.
Reversed-phase high-performance liquid chromatography with ultraviolet detection is the dominant approach for peptide purity assessment, usually paired with mass spectrometry to confirm molecular mass and sequence. Peptide mapping by enzymatic digestion and tandem mass spectrometry locates modifications such as deamidation and oxidation. Quantitation in plasma matrices can be performed by LC-MS/MS after solid-phase extraction. Method validation follows general guidance on accuracy, precision, linearity, and limits of detection. Comparability of results between laboratories, when no shared reference standard is available, remains an open question.
Stability studies focus on deamidation of asparagine and glutamine residues, oxidation of methionine, and aggregation into higher-order species. The fatty acid side chain adds susceptibility to oxidative change and can promote self-association at high concentration. Lyophilised material is comparatively robust when kept cold and dry, while aqueous solutions require refrigeration and protection from light. Forced degradation experiments under heat, acid, base, and peroxide conditions establish the specificity of each analytical method. Which degradation route dominates under real storage conditions depends on the formulation and stays formulation-specific.
| Property | Value | Notes |
|---|---|---|
| Molecular formula | C187H291N45O59 | free base, without counter-ion |
| Molecular weight | About 4114 Da | peptide backbone plus attached lipid chain |
| Plasma half-life | About 165 hours | supports once-weekly dosing in humans |
| Plasma protein binding | Greater than 99 percent | attributed mainly to serum albumin |
| Receptor target | GLP-1 receptor | Gs-coupled, raises intracellular cyclic AMP |
The sequence incorporates alpha-aminoisobutyric acid at position 8, replacing the alanine found in the natural hormone. This substitution blocks the primary DPP-4 recognition site and contributes most of the enzymatic stability. Albumin binding further protects the peptide and reduces the frequency of administration required to maintain active plasma levels. Because the fatty acid chain increases lipophilicity, the compound is formulated as a solution rather than a simple aqueous buffer. Researchers describe the design as an incremental optimization of earlier GLP-1 analogs rather than a wholly new scaffold.
Reported molecular weight is approximately 4113.6 daltons for the free base, and the peptide is supplied as a lyophilized powder or in buffered liquid form depending on the intended use. It is freely soluble in water when formulated with appropriate excipients, though the unconjugated peptide shows limited stability at neutral pH over long periods. Analytical characterization typically relies on reversed-phase high-performance liquid chromatography and mass spectrometry. Purity specifications for research-grade material commonly exceed ninety-five percent by area. Isotopic and impurity profiles differ between suppliers.
Receptor activation occurs at GLP-1 receptors distributed across pancreatic islets, the hypothalamus, and the gastrointestinal tract. Binding triggers G protein signaling that raises cyclic AMP and enhances glucose-dependent insulin release. Because the effect depends on prevailing glucose levels, insulin secretion does not rise when blood sugar is already low. Signaling in the brain and gut also influences appetite and gastric emptying, which is why the compound appears in both metabolic and weight-related research literature.
Development began in the early 2010s with the goal of extending GLP-1 activity beyond the brief window achieved by native peptide infusion. The earliest approved formulation was a subcutaneous injection given once weekly. A later oral tablet pairs the peptide with an absorption enhancer, sodium N-(8-[2-hydroxybenzoyl] amino) caprylate, usually shortened to SNAC. That carrier lowers local pH and helps the peptide cross gastric tissue. Both routes deliver the same active molecule.
Semaglutide is a synthetic peptide analog of human glucagon-like peptide-1, a gut hormone released after meals. Its backbone retains the GLP-1 sequence but incorporates two substitutions that slow enzymatic breakdown by dipeptidyl peptidase-4. A short polyethylene glycol linker and a C18 fatty diacid are attached to the peptide chain, allowing the molecule to bind serum albumin and remain in circulation far longer than the native hormone. The result is a circulating half-life measured in days rather than the minutes typical of endogenous GLP-1.
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.
=== Medications === The antifibrotics pirfenidone and nintedanib have been shown to slow the decline in lung function (as measured by forced vital capacity [FVC]) in those with ILD compared to placebo. Pirfenidone was associated with a 45% less decline in FVC at 52 weeks compared to placebo in a trial involving people with idiopathic pulmonary fibrosis, and was associated with a slower FVC decline in those with progressive pulmonary fibrosis. Nintedanib was also associated with a slower FVC decline and increased mean survival in people with ILD. The immunomodulator tocilizumab has a benefit in scleroderma associated ILD by helping to preserve lung function (as measured by FVC) at 48 weeks. The immunomodulators cyclophosphamide, mycophenolate mofetil and rituximab all showed improved lung function (as measured by % predicted FVC) compared to placebo in systemic sclerosis or scleroderma associated ILD. The inhaled vasodilator treprostinil (a synthetic prostacyclin which acts as a prostaglandin I2 analogue) is indicated in the treatment of pulmonary hypertension secondary to interstitial lung disease and is associated with improved exercise capacity as measured by a 6-minute walk test.
Amphetamine, discovered before methamphetamine, was first synthesized in 1887 in Germany by Romanian chemist Lazăr Edeleanu who named it phenylisopropylamine. Shortly after, methamphetamine was synthesized from ephedrine in 1893 by Japanese chemist Nagai Nagayoshi. Three decades later, in 1919, methamphetamine hydrochloride was synthesized by pharmacologist Akira Ogata via reduction of ephedrine using red phosphorus and iodine. From 1938, methamphetamine was marketed on a large scale in Germany as a nonprescription drug under the brand name Pervitin, produced by the Berlin-based Temmler pharmaceutical company. It was used by all branches of the combined armed forces of the Third Reich, for its stimulant effects and to induce extended wakefulness. Pervitin became colloquially known among the German troops as "Stuka-Tablets" (Stuka-Tabletten) and "Herman-Göring-Pills" (Hermann-Göring-Pillen), as a snide allusion to Göring's widely-known addiction to drugs. However, the side effects, particularly the withdrawal symptoms, were so serious that the army sharply cut back its usage in 1940. By 1941, usage was restricted to a doctor's prescription, and the military tightly controlled its distribution. Soldiers would only receive a couple of tablets at a time, and were discouraged from using them in combat. Historian Łukasz Kamieński says,
18 June to 15 August The 101st Airborne Division launched Operation Montgomery Rendezvous in western Thừa Thiên Province to interdict PAVN infiltration routes and forestall attacks on Huế. The operation results in 393 PAVN killed and 87 U.S. killed.
=== Sample collection === Newborn screening tests are most commonly done from whole blood samples collected on specially designed filter paper, originally designed by Robert Guthrie. The filter paper is often attached to a form containing required information about the infant and parents. This includes date and time of birth, date and time of sample collection, the infant's weight and gestational age. The form will also have information about whether the baby has had a blood transfusion and any additional nutrition the baby may have received (total parenteral nutrition). Most newborn screening cards also include contact information for the infant's physician in cases where follow up screening or treatment is needed. The Canadian province of Quebec performs newborn screening on whole blood samples collected as in most other jurisdictions, and also runs a voluntary urine screening program where parents collect a sample at 21 days of age and submit it to a provincial laboratory for an additional panel of conditions. Newborn screening samples are collected from the infant between 24 hours and 7 days after birth, and it is recommended that the infant has fed at least once. Individual jurisdictions will often have more specific requirements, with some states accepting samples collected at 12 hours, and others recommending to wait until 48 hours of life or later. Each laboratory will have its own criteria on when a sample is acceptable, or if another would need to be collected. Samples can be collected at the hospital, or by midwives.
==== Pneumococcal vaccine ==== In 2010, as part of a 10-year pneumococcal vaccine Advance Market Commitment, the companies GlaxoSmithKline (GSK) and Pfizer were both allocated $225 million in AMC subsidies to provide 30 million doses annually at a maximum tail price of $3.50 per dose ($10.50 per child for three doses). In 2011, Médecins Sans Frontières (MSF) recommended that Gavi change the ways in which it procures vaccines. MSF argued that the Advance Market Commitment had transferred more money to GSK and Pfizer than the Gavi grants had transferred to low-cost suppliers for technology transfer and product development. MSF said that large pharmaceutical multinationals had been found to put very high markups on prices, and internationally certified vaccine could be made for about 40% less cost by smaller companies in India and China, despite patent-related obstacles. In January 2015, MSF also called upon GSK and Pfizer to cut the price of the pneumococcal vaccine to US$5 per child in developing countries, a price they estimated as competitive. They said that, as Pfizer had made $16 billion in revenue on pneumococcal vaccine in the last four years, a larger price cut would be affordable. In early 2016, they ran the "A fair shot" campaign to pressure GSK and Pfizer to drop prices. Pfizer said that they were already selling the vaccine at "far below" cost, while GSK said that the price enabled them to "just about" cover their costs, and "To discount it further would threaten our ability to supply it to these countries in the long-term".
Sources: en.wikipedia.org
=== Bio-based coloured materials === Cellulose nanocrystals have shown the possibility to self organize into chiral nematic structures with angle-dependent iridescent colours. It is thus possible to manufacture totally bio-based pigments and glitters, films including sequins having a metallic glare and a small footprint compared to fossil-based alternatives.
==== 1956–60 ==== In 1956, Sports Illustrated wrote that Mizell's return would help with St. Louis's pitching, a "major problem" for the Cardinals in 1955. His first outing back on April 17 was triumphant, as he allowed 12 hits but just two runs and came within one out of a complete game in a 4–2 victory over the Cincinnati Redlegs. From May 21 through June 9, he won five straight games, though he followed that up with three straight losses from June 15 through June 26. During the winning streak, in the second game of a May 27 doubleheader, he struck out 10 hitters in a 12–2 victory over the Chicago Cubs. In the first game of a doubleheader against Pittsburgh on August 23, he threw a four-hit shutout in a 3–0 victory. On September 7, 1956, facing the Redlegs, who were second to the Braves in a close pennant race, Mizell threw a two-hit shutout in a 1–0 victory. Six days later, he threw his second consecutive shutout, beating the Giants 5–0 and allowing just four hits. He had a 3.62 ERA for the Cardinals in 1956, and his 14–14 mark was reflective of St. Louis's .500 record. Mizell's 14 wins tied with Ron Kline and Hersh Freeman for 10th in the NL, but his 14 losses tied with Sam Jones, Al Worthington, and teammate Tom Poholsky for sixth. He ranked fifth in the NL with 153 strikeouts, and his mark of 6.6 strikeouts per nine innings pitched was good for third behind Jones's 8.4 and Harvey Haddix's 6.6. However, his 92 walks were third in the NL, behind Jones's 115 and Bob Buhl's 105.
spindle apparatus The cytoskeletal structure that forms during cell division in eukaryotic cells, consisting of a network of long, flexible microtubules extending from each pole of the parent cell and attaching to kinetochores at the centromeres of homologous chromosomes or sister chromatids near the cell equator. As the microtubules shorten, they pull the chromosomes apart, separating them into different daughter cells. Proper formation of this apparatus is critical in both mitosis and meiosis, where it is respectively referred to as the mitotic spindle and meiotic spindle.
Free radical grafting of macromolecules (as the functional group) onto the surface of CNTs can improve the solubility of CNTs compared to acid treatments which involve the attachment of small molecules such as hydroxyl onto the surface of CNTs. The solubility of CNTs can be improved significantly by free-radical grafting because the large functional molecules facilitate the dispersion of CNTs in a variety of solvents even at a low degree of functionalization. Recently an environmentally friendly approach has been developed for the covalent functionalization of multi-walled carbon nanotubes (MWCNTs) using clove buds. This approach is innovative and green because it does not use toxic and hazardous acids which are typically used in common carbon nanomaterial functionalization procedures. The MWCNTs are functionalized in one pot using a free radical grafting reaction. The clove-functionalized MWCNTs are then dispersed in water producing a highly stable multi-walled carbon nanotube aqueous suspension (nanofluids). The surface of carbon nanotubes can be chemically modified by coating spinel nanoparticles by hydrothermal synthesis and can be used for water oxidation purposes. In addition, the surface of carbon nanotubes can be fluorinated or halofluorinated by heating while in contact with a fluoroorganic substance, thereby forming partially fluorinated carbons (so-called Fluocar materials) with grafted (halo)fluoroalkyl functionality.
Bowen–Conradi syndrome (BCS or BWCNS) is an autosomal recessive abnormality of the EMG1 gene, which plays a role in small ribosomal subunit (SSU) assembly. Most affected children have been from North American Hutterite families, but BWCNS can affect other population groups. Skeletal dysmorphology is seen and severe prenatal and postnatal growth failure usually leads to death by one year of age.
Sources: en.wikipedia.org
Native GLP-1 is a short-lived peptide cleared within one to two minutes by dipeptidyl peptidase-4 and related enzymes. Semaglutide keeps the receptor-binding backbone but adds substitutions and a lipid chain. These changes block the main cleavage site and allow reversible albumin binding, extending the half-life to roughly 165 hours.
Albumin is the most abundant protein in plasma and carries molecules that bear fatty-acid chains. Binding shields the peptide from renal filtration and from peptidases, keeping a circulating reservoir. Slow release from this reservoir produces sustained receptor occupancy and supports infrequent dosing.
The insulinotropic effect is glucose-dependent, meaning secretion increases mainly when glucose is elevated. This property is often described as lowering the chance of hypoglycaemia when the compound is used alone. Other glucose-lowering agents used at the same time can still cause low blood glucose.
Purity is commonly expressed as the percentage of the main peak relative to all integrated peaks in a reversed-phase chromatogram. Related substances and counter-ions are reported separately. Values obtained with different detectors are not always directly comparable.