This is a working overview of 冻干制剂, written for readers who want more than a one-paragraph summary but less than a textbook.
This page was last updated on 2026-05-22 and is reviewed periodically as new material appears.
纯度评价多采用反相高效液相色谱，流动相常加入三氟乙酸或甲酸作为离子对改性剂，检测波长设在二百一十四纳米或二百二十纳米。分子量确认依靠电喷雾电离质谱或基质辅助激光解吸电离质谱，实测值应与理论值在数 ppm 内吻合。肽图分析通过酶切后液相色谱串联质谱完成，用于核查序列与修饰位点。体积排阻色谱用于定量共价与非共价聚集体。生物基质浓度测定则采用免疫分析或液相色谱串联质谱。
肽类的主要降解路径包括天冬酰胺脱酰胺、甲硫氨酸氧化、天冬氨酸异构化以及由 β-折叠驱动的聚集，这些反应对 pH 与缓冲液种类较为敏感。磷酸盐、丙二醇与苯酚等辅料会影响局部微环境与界面行为。强制降解研究借助高温、强光、氧化剂与极端 pH 暴露来预测产物谱。关于长期室温存放的数据相对有限，超出标签条件的稳定性仍属开放问题，需要在具体制剂中通过实时与加速试验加以确认。
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.
Peptides are sensitive to temperature, light, oxygen, and repeated freeze-thaw cycles. Semaglutide in dry form is generally held at refrigerated temperatures, while reconstituted solutions require a defined short-term storage window. Vials should be kept in secondary packaging to limit photodegradation, and exposure to alkaline conditions is avoided because it accelerates chemical degradation. Adsorption to glass and some plastics can reduce the measured concentration of dilute solutions, so low-binding polypropylene containers are preferred for analytical work. Each transfer step introduces a small risk of contamination, and closed handling practices reduce that risk.
| Property | Value | Notes |
|---|---|---|
| 保存温度 | 2 至 8 摄氏度 | 避免冻结，部分制剂允许短期室温 |
| 粉末外观 | 白色至类白色固体 | 吸湿后易结块 |
| 纯度检测方法 | 反相高效液相色谱 | 紫外检测，常用 214 纳米 |
| 分子量确认方法 | 液相色谱串联质谱 | 偏差通常以 ppm 表示 |
| 常见降解产物 | 氧化与脱酰胺变体 | 源自甲硫氨酸与天冬酰胺残基 |
Reversed-phase high-performance liquid chromatography is widely used to assess purity and to separate the parent peptide from related substances. Mass spectrometry confirms identity and can resolve modifications that differ by a few daltons. Size-exclusion chromatography detects dimers and higher aggregates, which are relevant to both stability and immunogenicity questions. Peptide mapping with enzymatic digestion locates specific modifications along the sequence. Circular dichroism provides a secondary-structure profile, although it gives limited information about local conformational changes.
Quality control for peptide material focuses on identity, purity, content and the profile of impurities. Common degradants include deamidated and oxidised forms, plus aggregates formed during storage or handling. Forced degradation studies under heat, light, acid and peroxide help define which conditions accelerate change and which analytical methods detect it. Limits for individual impurities are set by pharmacopoeial monographs or manufacturer specifications. How much a given impurity affects biological activity is often uncertain, and conclusions may depend on the assay used.
Quality control for research material typically involves reversed-phase HPLC for purity and identity, mass spectrometry for molecular weight confirmation, and Karl Fischer titration for residual water content. Peptide content is often reported as the mass of actual peptide rather than total powder mass, since counterions and water contribute to the latter. A certificate of analysis should list the method used for each specification. Limits and acceptance criteria vary by supplier and by intended application.
Handling practices center on minimizing contamination and adsorption. Lyophilized peptide tends to accumulate static charge, so weighing is done with antistatic measures and calibrated balances. Reconstitution with appropriate solvent should be gentle, avoiding vigorous vortexing that generates foam and shear. Solutions are typically aliquoted before freezing to reduce repeated temperature cycling. Personal protective equipment and a fume hood are standard for powder handling.
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.
DNA methylation is a widespread mechanism for epigenetic influence on gene expression and is seen in bacteria and eukaryotes and has roles in heritable transcription silencing and transcription regulation. Methylation most often occurs on a cytosine (see Figure). Methylation of cytosine primarily occurs in dinucleotide sequences where a cytosine is followed by a guanine, a CpG site. The number of CpG sites in the human genome is about 28 million. Depending on the type of cell, about 70% of the CpG sites have a methylated cytosine. Methylation of cytosine in DNA has a major role in regulating gene expression. Methylation of CpGs in a promoter region of a gene usually represses gene transcription while methylation of CpGs in the body of a gene increases expression. TET enzymes play a central role in demethylation of methylated cytosines. Demethylation of CpGs in a gene promoter by TET enzyme activity increases transcription of the gene.
=== Liquid-liquid equilibrium calculations === In order to calculate the phase equilibrium, it is necessary to use a thermodynamic model such as NRTL, UNIQUAC, etc. The corresponding parameters of these models can be obtained from literature (e.g. Dechema Chemistry Data Series, Dortmund Data Bank, etc.) or by a correlation process of experimental data.
when she went to see her brother Rubén who was extradited in the US for drug trafficking. She was charged with engaging in transactions or dealings in properties with businesses blacklisted by the Treasury Department and providing financial support to the CJNG. She pleaded guilty on 12 March 2021, and on 11 June was sentenced to 21⁄2 years in prison. On 11 March 2020, the U.S. Drug Enforcement Administration (DEA) arrested 600 people and seized more than a ton and a half of narcotics. This is the DEA's largest-ever strike against CJNG. The number of arrests was revised to 750, with 250 arrests occurring in the United States. On 10 April 2020, Oseguera's Chicago area lieutenant Luis Alderate was arrested. Other high-level associates of Oseguera prosecuted in Chicago include Diego Pineda-Sanchez, sentenced to 15 years in prison for laundering money for him and other drug kingpins, and Carlos Perra-Pedroza, sentenced to 13 years in prison for similar charges. Alderate's brother Roberto Alderete was arrested in Kentucky in 2018 with two pounds of methamphetamine. On 11 April 2020, CJNG cell leader María del Carmen Albarrán was arrested in the Venustiano Carranza borough of Mexico City. In May 2020, it was reported that former CJNG security chief Enrique Alejandro Pizano, who was arrested in September 2015 died in a Jalisco prison on 13 May 2020 due to COVID-19. On 28 June 2020, it was reported that the number of CJNG members arrested for 26 June 2020 assassination attempt of the Mexican City Police Chief had grown to 19.
=== Co-release === Neuropeptides are often co-released with other neurotransmitters and neuropeptides to modulate synaptic activity. Synaptic vesicles and dense core vesicles can have differential activation properties for release, resulting in context-dependent co-release combinations. For example, insect motor neurons are glutamatergic and some contain dense core vesicles with proctolin. At low frequency activation, only glutamate is released, yielding fast and rapid excitation of the muscle. At high frequency activation however, dense core vesicles release proctolin, inducing prolonged contractions. Thus, neuropeptide release can be fine-tuned to modulate synaptic activity in certain contexts. Some regions of the nervous system are specialized to release distinctive sets of peptides. For example, the hypothalamus and the pituitary gland release peptides (e.g. TRH, GnRH, CRH, SST) that act as hormones In one subpopulation of the arcuate nucleus of the hypothalamus, three anorectic peptides are co-expressed: α-melanocyte-stimulating hormone (α-MSH), galanin-like peptide, and cocaine-and-amphetamine-regulated transcript (CART), and in another subpopulation two orexigenic peptides are co-expressed, neuropeptide Y and agouti-related peptide (AGRP). These peptides are all released in different combinations to signal hunger and satiation cues. The following is a list of neuroactive peptides co-released with other neurotransmitters. Transmitter names are shown in bold. Norepinephrine (noradrenaline).
== History == Buprenorphine was first synthesised from thebaine in 1966. In 1969, researchers at Reckitt and Colman (now Reckitt Benckiser) had spent 10 years attempting to synthesize an opioid compound "with structures substantially more complex than morphine [that] could retain the desirable actions whilst shedding the undesirable side effects". Physical dependence and withdrawal from buprenorphine itself remain important issues since buprenorphine is a long-acting opioid. Reckitt found success when researchers synthesized RX6029 which had shown success in reducing dependence in test animals. RX6029 was named buprenorphine and began trials on humans in 1971. Buprenorphine was approved for use in humans in 1977 in the UK and 1982 in the US. Buprenorphine was first used in dogs in the 1980s and in cats in the 1990s. A 0.3mg/ml formulation for use in cats was approved in 1995, a higher strength 1.8mg/ml formulation was approved in 2014, and a transdermal patch was approved in 2022.
Sources: en.wikipedia.org
=== Legal status === In July 2021, the Committee for Medicinal Products for Human Use (CHMP) of the European Medicines Agency (EMA) adopted a positive opinion, recommending the granting of a marketing authorization for the medicinal product Nexviadyme, intended for the treatment of glycogen storage disease type II (Pompe disease). The applicant for this medicinal product is Genzyme Europe BV. In August 2021, Genzyme Europe BV requested a re-examination. Avalglucosidase alfa was approved for medical use in the European Union in June 2022. The U.S. Food and Drug Administration (FDA) granted the application for avalglucosidase alfa fast track, priority review, breakthrough therapy, and orphan drug designations. The FDA granted the approval of Nexviazyme to Genzyme Corporation.
=== Neurodegenerative mechanisms === Arsenic is highly detrimental to the innate and the adaptive immune system of the body. When the amount of unfolded and misfolded proteins in endoplasmic reticulum stress is excessive, the unfolded protein response (UPR) is activated to increase the activity of several receptors that are responsible the restoration of homeostasis. The inositol-requiring enzyme-1 (IRE1) and protein kinase RNA-like endoplasmic reticulum kinase (PERK) are two receptors that restrict the rate of translation. On the other hand, the unfolded proteins are corrected by the production of chaperones, which are induced by the activating transcription factor 6 (ATF6). If the number of erroneous proteins elevates, further mechanism is active which triggers apoptosis. Arsenic has evidentially shown to increase the activity of these protein sensors.
5,000–7,200 species of red algae worldwide "some 1,300 in Australian Seas" 400 seaweed species for the western coastline of South Africa, and 212 species from the coast of KwaZulu-Natal. Some of these are duplicates, as the range extends across both coasts, and the total recorded is probably about 500 species. Most of these are listed in List of seaweeds of South Africa. These exclude phytoplankton and crustose corallines. 669 marine species from California (US) 642 in the check-list of Britain and Ireland and so on, but lacking any scientific basis or reliable sources, these numbers have no more credibility than the British ones mentioned above. Most estimates also omit microscopic algae, such as phytoplankton.
== Discovery == Motilin was discovered by J.C. Brown when he introduced alkaline solution into duodena of dogs, which caused strong gastric contractions. Brown et al. predicted that alkali could either release stimulus to activate motor activity or prevent the secretion of inhibitory hormone. They isolated a polypeptide as a by-product from purification of secretin on carboxymethyl cellulose. They named this polypeptide "Motilin."
Sources: en.wikipedia.org
The dalton (symbol: Da), or unified atomic mass unit (symbol: u), is a unit of mass defined as 1/12 of the mass of an unbound neutral atom of carbon-12 in its nuclear and electronic ground state and at rest. The word "unified" emphasizes that the definition was jointly accepted by physics (IUPAP) and chemistry (IUPAC) organizations. The atomic mass constant, denoted mu, is an atomic-scale reference mass, defined identically, but it is not a unit of mass. Expressed in terms of ma(12C), the atomic mass of carbon-12: mu = ma(12C)/12 = 1 Da. A proton has a mass that is approximately equal to 1 dalton. The value serves as a conversion factor of mass from daltons to kilograms, which can easily be converted to grams and other metric units of mass. The 2019 revision of the SI redefined the kilogram by fixing the value of the Planck constant (h), improving the precision of the atomic mass constant expressed in SI units by anchoring it to fixed physical constants. Although the dalton remains defined via carbon-12, the revision enhances traceability and accuracy in atomic mass measurements.
Under President John F. Kennedy, US troop levels in Vietnam grew from just under a thousand in 1959 to 16,000 in 1963. South Vietnamese President Ngo Dinh Diem's heavy-handed crackdown on Buddhist monks in 1963 led the US to endorse a deadly military coup against Diem. The war escalated further in 1964 following the controversial Gulf of Tonkin incident, in which a US destroyer was alleged to have clashed with North Vietnamese fast attack craft. The Gulf of Tonkin Resolution gave President Lyndon B. Johnson broad authorization to increase US military presence, deploying ground combat units for the first time and increasing troop levels to 184,000. Soviet leader Leonid Brezhnev responded by reversing Khrushchev's policy of disengagement and increasing aid to the North Vietnamese, hoping to entice the North from its pro-Chinese position. The USSR discouraged further escalation of the war, however, providing just enough military assistance to tie up American forces. From this point, the People's Army of Vietnam (PAVN) engaged in more conventional warfare with US and South Vietnamese forces. The Tet Offensive of 1968 proved to be the turning point of the war. Despite years of American tutelage and aid, the South Vietnamese forces were unable to withstand the communist offensive and the task fell to US forces instead. At the same time, in 1963–1965, American domestic politics saw the triumph of liberalism. According to historian Joseph Crespino:
CSL Limited is an Australian multinational specialty biotechnology company that researches, develops, manufactures, and markets products to treat and prevent serious human medical conditions. CSL's product areas include blood plasma derivatives, vaccines, antivenom, and cell culture reagents used in various medical and genetic research and manufacturing applications. The company was established in 1916 as Commonwealth Serum Laboratories and was wholly owned by the Australian federal government until its privatisation in 1994.
T4 is a haplogroup unique to East Asia that is not observed in Near Eastern, European, and African cattle, and T3 is the predominant haplogroup in European cattle, but T3 is also predominant in Korean cattle. This means that the present breed of Korean cattle is not the main ancestor of the Wagyu. In addition, haplogroup P has additionally been detected in about 46% of the Japanese Shorthorn. It has been detected in many extinct European aurochs, but has only been found in a total of three current livestock cattle—one Chinese and two Korean—out of several thousand individuals in the database. The Japanese Shorthorn was created by crossing the Nanbu cattle bred in the former Nanbu Domain territory in northeastern Japan (present-day Iwate Prefecture) with Shorthorns and other breeds imported from the United States, but P has not been detected in Shorthorns and is thought to be derived from the Nanbu cattle. Fossils of Hanaizumi Moriushi and Aurochs have been found in Iwate Prefecture, but it is unclear if the Nanbu cattle were related to these. Haplogroup P has also been found in Chinese and Korean cattle, but it is extremely rare compared to T4. Therefore, it is suggested that the ancestors of the Nanbu cattle have a different origin from the ancestors of the Japanese Black in western Japan, where T4 is abundant, and that there is no single ancestor of the Wagyu.
The low budget of the project proved to be a significant challenge, as well as the unique challenges of working with child actors. The producers wanted the style of the series to reflect trends begun in other popular and innovative TV shows such as Sesame Street and Laugh-In. Puppetry and animation were frequently used. Sometimes one or two of the kids would conduct "man-on-the-street" interviews, asking ordinary citizens about nutrition-related topics. All of the music, including the theme song and the various songs sung by the kids during an episode (many times in musical "romps" reminiscent of the ones seen on The Monkees TV series), were composed and arranged by Washington, DC musician and recording engineer Paul Brier, and performed by a rock combo credited on screen as "The Eye". Mulligan Stew premiered on October 4, 1972, during the National 4-H Week at the National 4-H Center in Washington, DC. The program was considered a success, especially by previous standards for television outreach sponsored by 4-H. The series had a moderate impact on kids making better choices in what they ate, and provided 4-H with a sizable marketing, promotional and public relations boost. Thanks in part to the popularity of Mulligan Stew, 4-H membership was boosted to an all-time high in 1974, and the series continued to air in reruns on public television until 1981.
Sources: en.wikipedia.org
冻融过程中冰晶形成与局部浓度升高会促使肽链发生界面吸附和聚集。聚集不仅降低有效含量，还会改变可见异物与不溶性微粒的计数结果。将溶液分装为单次使用的小体积等份可减少循环次数。
该方法依据疏水性差异分离主峰与相关杂质，对缺失序列、氧化产物和脱酰胺变体具有较好分辨能力。流动相中加入离子对试剂可改善峰形。紫外检测在肽键吸收区工作，灵敏度足以支持常规放行检验。
加速条件可以放大多数化学降解，但聚集与界面诱导的变化对容器、摇动和温度历史更敏感。某些固态转变在短时高温下不一定出现。因此实时稳定性数据仍不可替代，加速结果一般只作为趋势参考。
Different techniques detect different classes of impurities, so a single number does not describe a sample completely. Reversed-phase chromatography resolves related peptides well but can miss inorganic salts, while mass spectrometry confirms mass without quantifying everything present. Comparing results requires knowing which method was used and how it was validated.