The short version of Adsorption fits in a sentence. The long version — which is the one that helps — is below.
Reviewed 2026-01-19. Anything still debated is marked as such rather than presented as settled.
The company that developed the compound filed it as a long-acting analogue, and it gained first approval in 2017 for type 2 diabetes. Later authorisations from several regulators extended the indication to chronic weight management, and the World Health Organization added the glucagon-like peptide-1 receptor agonist drug class to its model list of essential medicines in 2023. Production uses solid-phase peptide synthesis followed by side-chain conjugation and chromatographic purification. Supply constraints and cost differences across regions are well documented. Literature on long-term outcomes continues to grow, with many trials reporting surrogate endpoints rather than hard clinical endpoints.
Semaglutide is a synthetic peptide of thirty-one amino acids that shares roughly ninety-four percent sequence identity with human glucagon-like peptide-1. Two substitutions resist enzymatic cleavage by dipeptidyl peptidase-4, and a fatty diacid side chain attached through a linker promotes binding to serum albumin. That albumin binding slows renal clearance and extends the circulating half-life from minutes to approximately one week. The structural changes are well established in the published literature. Whether the same modifications affect receptor signalling bias in ways that matter clinically remains an open question.
Activation of the GLP-1 receptor couples to Gs signalling and raises intracellular cyclic AMP in pancreatic beta cells. The resulting insulin release depends on prevailing glucose concentrations, so the effect is greater when glucose is elevated. Receptor engagement also suppresses glucagon secretion and slows gastric emptying, which flattens post-meal glucose excursions. In the central nervous system, signalling in hypothalamic and brainstem regions is associated with reduced appetite and lower energy intake. Studies continue to examine effects on cardiac, renal and hepatic endpoints; whether those benefits are independent of weight change remains an open question.
Clinical development of this compound followed earlier short-acting GLP-1 analogues that required frequent injection. Once-weekly subcutaneous formulations entered use after 2017, and an oral formulation using a permeation enhancer later became available. The oral version pairs the peptide with sodium N-(8-[2-hydroxybenzoyl] amino) caprylate, a carrier that improves uptake across the gastric epithelium. Interest has expanded from glycaemic control into weight management and metabolic liver disease. Regulatory status and approved indications differ between countries, and the product remains subject to ongoing safety monitoring.
Semaglutide is a synthetic peptide that acts as an agonist at the glucagon-like peptide-1 receptor. It is a structural analogue of human GLP-1(7-37), modified to resist enzymatic degradation by dipeptidyl peptidase-4. The peptide backbone contains alpha-aminoisobutyric acid at position 8, a substitution that stabilises the helix and slows cleavage. A fatty diacid side chain attached through a linker at lysine 34 promotes binding to serum albumin, which extends the circulating half-life. These two modifications together allow less frequent administration than native GLP-1 requires.
| Property | Value | Notes |
|---|---|---|
| Molecular class | 31-amino-acid peptide | Modified glucagon-like peptide-1 analogue |
| Molecular mass | approximately 4114 Da | Calculated for the free peptide backbone |
| Appearance | white to off-white powder | Typical of purified lyophilised peptide batches |
| Solubility class | freely soluble in water | Aqueous solubility improves at slightly alkaline pH |
| Typical storage | -20 degrees Celsius, dry, dark | Protect from repeated freeze-thaw cycles |
Lyophilised material appears as a white to off-white cake or powder that is hygroscopic, and containers are usually equilibrated to room temperature before opening to limit condensation. Dissolution is performed in water, phosphate-buffered saline, or a mildly alkaline buffer, since solubility rises above neutral pH. Gentle inversion or low-speed mixing is preferred, because vigorous vortexing can promote surface denaturation and aggregation. Complete dissolution may require several minutes, and brief sonication is sometimes applied. Passing the solution through a 0.22 micrometre membrane removes particulates but does not by itself sterilise the liquid.
Storage at minus 20 degrees Celsius or lower in a desiccated container preserves the peptide for extended periods, while working solutions are commonly held at two to eight degrees Celsius for short intervals. Light exposure and repeated freeze-thaw cycles accelerate degradation, so dividing material into single-use aliquots is generally recommended. Adsorption to glass and plastic surfaces can lower the measured concentration of dilute solutions, particularly below one milligram per millilitre. The degradation routes most often reported for GLP-1 analogues are deamidation, methionine oxidation, and backbone hydrolysis. Relative rates under specific conditions are frequently described only for individual formulations.
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.
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.
该分子作为 GLP-1 受体的选择性激动剂发挥作用，受体属于 B 类 G 蛋白偶联受体家族，激活后经 Gs 通路提升细胞内环腺苷酸水平。在胰腺 β 细胞，信号促进葡萄糖依赖性的胰岛素释放，血糖偏低时该作用明显减弱。在胰岛 α 细胞，胰高血糖素分泌受到抑制。中枢神经系统与胃肠道同样存在受体表达，相应信号参与食欲调节以及胃排空速率的降低。
皮下注射后吸收相对缓慢，绝对生物利用度约为百分之八十九，血药浓度峰值通常出现在给药后一到三天。与白蛋白结合使清除减慢，终末半衰期约为一百六十五小时，接近一周。连续给药约四到五周后达到稳态暴露水平。表观分布容积约为每千克零点二五升，血浆蛋白结合率超过百分之九十九。代谢以蛋白水解切割和脂肪二酸侧链的 β-氧化为主，相关产物主要经尿液与粪便排出。
Freeze drying, also known as lyophilization or cryodesiccation, is a low-temperature dehydration process that involves freezing the product and lowering pressure, thereby removing the ice by sublimation. This is in contrast to dehydration by most conventional methods that evaporate water using heat. Because of the low temperatures used in processing, the rehydrated product retains many of its original qualities. When solid objects like strawberries are freeze dried the original shape of the product is maintained. If the product to be dried is a liquid, as often seen in pharmaceutical applications, the properties of the final product are optimized by the combination of excipients (i.e., inactive ingredients). Primary applications of freeze drying include biological (e.g., bacteria and yeasts), biomedical (e.g., surgical transplants), food processing (e.g., coffee), and food preservation.
=== Cultural === The Houthis have also held a number of mass gatherings since the revolution. On 24 January 2013, thousands gathered in Dahiyan, Sa'dah and Heziez, just outside Sanaa, to celebrate Mawlid al-Nabi, the birth of Mohammed. A similar event took place on 13 January 2014 at the main sports' stadium in Sanaa. On this occasion, men and women were completely segregated: men filled the open-air stadium and football field in the centre, guided by appointed Houthi safety officials wearing bright vests and matching hats; women poured into the adjacent indoor stadium, led inside by security women distinguishable only by their purple sashes and matching hats. The indoor stadium held at least five thousand women—ten times as many attendees as the 2013 gathering.
pH-responsive hydrogel dressings release growth factors and antibiotic agents as the pH of the wound increases from normal skin levels (pH 4–6) to internal levels (pH ~7.4). Redox-responsive hydrogel dressings can be disintegrated on-demand by addition of a reducing agent. Assembly of the 3D network of photoresponsive hydrogel dressings is initiated by UV radiation. Thermoresponsive hydrogel dressings exhibit temperature-dependent sol-gel transition and/or temperature-dependent drug release.
Quinolinate synthase (EC 2.5.1.72, NadA, QS, quinolinate synthetase) is an enzyme with systematic name glycerone phosphate:iminosuccinate alkyltransferase (cyclizing). This enzyme catalyses the following chemical reaction
Sources: en.wikipedia.org
On May 30, 2024, Trump was found guilty by a jury of all 34 felony counts in The People of the State of New York v. Donald J. Trump. The jury found that Trump falsified business records relating to hush money payments made to pornographic film star Stormy Daniels to ensure her silence about a sexual encounter between them. This conviction made Trump the first former U.S. president to be convicted of a crime. On January 10, 2025, Trump was given a no-penalty sentence known as an unconditional discharge. Trump faced other criminal charges as well. In United States of America v. Donald J. Trump, Trump faced four criminal counts for his alleged role in attempting to overturn the 2020 United States presidential election and involvement in the January 6 United States Capitol attack; the case was dismissed following Trump's re-election in November 2024. In The State of Georgia v. Donald J. Trump, et al., Trump was charged with eight criminal counts for his alleged attempts to overturn the results of the 2020 United States presidential election in Georgia. District Attorney Fani Willis was disqualified from prosecuting the case; Willis has appealed that decision. In United States of America v. Donald J. Trump, Waltine Nauta, and Carlos De Oliveira, Trump faced 40 criminal counts relating to his hoarding of classified documents and alleged obstruction of efforts to retrieve them; the case was dismissed in July 2024. On May 9, 2023, in E. Jean Carroll v. Donald J.
The CCP maintains absolute control over the PLA. It requires the PLA to undergo political education, instilling CCP ideology in its members. Additionally, China maintains a political commissar system. Regiment-level and higher units maintain CCP committees and political commissars (Chinese: 政治委员 or 政委). Additionally, battalion-level and company-level units respectively maintain political directors and political instructors. The political commissars are officially equal to commanders in status. The political commissars are officially responsible for the implementation of party committee decisions, instilling and maintaining party discipline, providing political education, and working with other components of the political work system. Key decisions in the PLA are generally made in the CCP committees throughout the military. As a rule, the political commissar serves as the party committee secretary while the commander serves as the deputy secretary. Political commissars report to higher-level party committees, rather than military commanders. Due to the CCP's system of absolute control, non-CCP political parties and groups and organizations except the Communist Youth League of China are not allowed to establish organizations or have members in the PLA. Additionally, only the CCP is allowed to appoint the leading cadres at all levels of the PLA.
2-Hydroxybutyrate, the conjugate base of 2-hydroxybutyric acid, is produced in mammalian tissues (principally hepatic) that catabolize L-threonine or synthesize glutathione. Oxidative stress or detoxification demands can dramatically increase the rate of hepatic glutathione synthesis. Under such metabolic stress conditions, supplies of L-cysteine for glutathione synthesis become limiting, so homocysteine is diverted from the transmethylation pathway forming methionine into the transsulfuration pathway forming cystathionine. 2-Hydroxybutyrate is released as a byproduct when cystathionine is cleaved to cysteine that is incorporated into glutathione. Chronic shifts in the rate of glutathione synthesis may be reflected by urinary excretion of 2-hydroxybutyrate. α-hydroxybutyrate may be useful as an early indicator of insulin resistance in non-diabetic subjects. Moreover, elevated serum α-hydroxybutyrate predicts worsening glucose tolerance.
Sources: en.wikipedia.org
It is a glucagon-like peptide-1 receptor agonist, often grouped with the incretin mimetics. Its backbone is modified from the human hormone to resist enzymatic degradation and to bind albumin. These two features distinguish it from the native peptide.
No. It shares high sequence identity but carries non-natural modifications that alter its stability and clearance. The naturally occurring hormone is broken down within minutes, while the synthetic analogue circulates far longer.
Attachment to serum albumin reduces renal filtration of the peptide and shields it from enzymatic breakdown. The consequence is a much longer interval between administrations than unmodified peptides allow. The precise contribution of binding affinity to overall duration is still being quantified.
It belongs to the incretin mimetic class and acts as a long-acting glucagon-like peptide-1 receptor agonist. The class includes several peptides with different half-lives and routes of administration.