If you have been reading about Collapse temperature 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.
Updated 2026-06-11. Numbers and descriptions here follow the published literature rather than marketing material.
The physical chemistry of freezing influences whether a formulation forms an amorphous glass or a crystalline solid. Amorphous systems can collapse if product temperature rises above the glass transition temperature of the freeze concentrate. Crystalline systems may show eutectic melting, where ice and solute melt together at a fixed temperature. Formulators add bulking agents, lyoprotectants, and buffers to preserve structure and biological activity. The optimum cycle keeps product temperature below critical thresholds during primary drying while allowing efficient sublimation.
Lyophilization is a dehydration process that removes water from a frozen material by sublimation under low pressure. The material is first frozen so that water becomes ice; then the surrounding pressure is lowered below the vapor pressure of ice. Heat is applied gently so ice changes directly to vapor without passing through a bulk liquid phase. The vapor is collected on a cold condenser, leaving a dry porous matrix. This process differs from simple evaporation because the material remains frozen during the main drying stage.
In practice, lyophilization is slower and more energy intensive than simple drying. Cycle times can range from hours to several days depending on load, container, and formulation. Amorphous materials may require excipients that help preserve structure during freezing and drying. The method is widely used for biological materials, pharmaceuticals, and foods where heat drying would cause unacceptable change. Open questions remain about scaling cycles between laboratory and production equipment, and this gap affects technology transfer.
Lyophilization removes water by freezing a material and then lowering pressure so ice changes directly to vapor. The process relies on sublimation, the phase transition from solid to gas without an intermediate liquid state. Because the material remains frozen during primary drying, the structure often stays porous. This porous matrix can rehydrate quickly when water is added back. The low pressure also allows vapor to leave the solid matrix without boiling.
| Property | Value | Notes |
|---|---|---|
| Common synonyms | Freeze-drying, lyophilisation | Lyophilisation is the British spelling; the process is not simple evaporation. |
| Primary drying pressure | 0.05–0.3 mbar | Pressure must remain below the vapor pressure of ice at the product temperature. |
| Sublimation temperature | Below 0 °C | Ice changes directly to vapor while the product remains frozen. |
| Typical shelf temperature | −40 to −10 °C | Exact setting depends on formulation critical temperature and equipment. |
| Cycle duration | 12–72 hours | Time varies with fill volume, formulation, and dryer performance. |
A typical cycle begins with freezing, sometimes including an annealing step to control ice crystal size. Freezing conditions influence the pore network that later allows vapor escape. During primary drying, shelf temperature and chamber pressure are set so heat enters the product while its temperature stays below the collapse or eutectic point. Secondary drying then raises the shelf temperature to desorb bound water and lower residual moisture. Cycle design depends on formulation, fill volume, container type, and equipment capability.
The physics of lyophilization couples heat transfer, mass transfer, and phase behavior. Sublimation requires a vapor pressure difference between the ice front and the chamber, and the dried layer adds resistance to vapor flow. Amorphous formulations are characterized by a glass transition temperature of the maximally freeze-concentrated solute, often denoted Tg'. Crystalline bulking agents can provide structure, while amorphous excipients stabilize labile components. Open questions remain about spatial heterogeneity, edge effects, and how laboratory cycles scale to production.
Lyophilization is a drying process in which a solvent, usually water, is removed from a frozen material by sublimation under reduced pressure. The material is first solidified, then placed under vacuum so that ice transitions directly to vapor without a bulk liquid phase. This approach suits heat-sensitive substances that would degrade during conventional evaporation. Primary drying removes unbound ice, while secondary drying reduces water that remains adsorbed to the solid matrix. The result is a porous, lightweight solid that can be reconstituted later.
Lyophilization, also called freeze-drying, is a dehydration process in which a solvent, usually water, is frozen and then removed by sublimation under reduced pressure. The method preserves heat-sensitive materials that would degrade in conventional drying. Large-scale use grew during the mid-twentieth century for blood plasma and antibiotics, and it later expanded to vaccines, enzymes, foods, and advanced materials. The process produces a dry, porous solid that usually reconstitutes rapidly. It is distinct from simple evaporation because the solvent bypasses the liquid phase during primary removal.
The process generally proceeds in three stages: freezing, primary drying, and secondary drying. During freezing, controlled cooling converts water into ice and may also crystallize or vitrify solutes. In primary drying, the pressure is lowered below the triple point, and heat is supplied so ice sublimes directly to vapor. Secondary drying removes water that remains bound to the solid matrix, yielding a low final water content. Product temperature must stay below the collapse or glass transition temperature to maintain structure. Cycle design therefore balances shelf temperature, chamber pressure, and time.
Lyophilization, also known as freeze-drying, is a process that removes water from a material by freezing it and then reducing pressure to allow ice to sublimate directly into vapor. The method begins with a freezing step that solidifies the water content. Next, primary drying lowers the pressure below the triple point of water, enabling sublimation without passing through a liquid phase. A final secondary drying step removes bound water through desorption. This sequence produces a dry, porous cake that can be reconstituted later.
The process relies on the phase diagram of water, where the triple point marks the conditions at which ice, liquid water, and vapor coexist. By maintaining pressure below this point, typically around 0.01 to 0.1 millibar, sublimation becomes the dominant mechanism. Formulations often include excipients such as sugars or polymers that act as lyoprotectants and bulking agents. These additives help preserve the structure of the active ingredient and prevent collapse during drying. The choice of excipient and freezing rate influences the final cake morphology and stability.
Industries use lyophilization for pharmaceuticals, biological products, and food preservation. In the pharmaceutical sector, it extends the shelf life of injectable drugs, vaccines, and proteins that are unstable in aqueous solution. Food manufacturers apply freeze-drying to coffee, fruits, and ready meals to retain flavor and texture. The process is energy-intensive and requires specialized equipment, which limits its use to high-value products. Ongoing research examines how formulation and process parameters affect the quality of the final dried product.
Lyophilization removes water from a frozen material by sublimation under reduced pressure. The process begins with freezing, which converts liquid water into ice and concentrates dissolved solids. Primary drying then lowers chamber pressure so ice changes directly into vapor without passing through a liquid phase. Secondary drying raises the shelf temperature to remove bound water that remains after ice sublimation. The result is a dry, porous structure that can be reconstituted later.
Formulation composition influences whether freeze-drying produces an intact cake or a collapsed mass. Excipients such as sugars and polymers can raise the collapse temperature and provide bulk during drying. The critical temperature for primary drying is often the collapse temperature or the glass transition temperature of the maximally concentrated phase. If the product temperature exceeds this threshold, the frozen matrix may soften and lose structure. Established practice therefore links shelf temperature and chamber pressure to the formulation's thermal properties.
== Vitamin B12 == Vitamin B12 plays an integral role in this reaction. Coenzyme B12 (adenosyl-cobalamin) is an organometallic form of vitamin B12 and serves as the cofactor of Methylmalonyl-CoA mutase, which is an essential enzyme in the human body. The transformation of Methylmalonyl-CoA to Succinyl-CoA by this enzyme is a radical reaction.
Actinium (89Ac) has no stable isotopes and no characteristic terrestrial isotopic composition, thus a standard atomic weight cannot be given. There are 34 known isotopes, from 203Ac to 236Ac, and 9 isomers. Three isotopes are found in nature, 225Ac, 227Ac and 228Ac, as intermediate decay products of, respectively, 237Np, 235U, and 232Th. 228Ac and 225Ac are extremely rare, so almost all natural actinium is 227Ac. The most stable isotopes are 227Ac with a half-life of 21.772 years, 225Ac with a half-life of 9.919 days, and 226Ac with a half-life of 29.37 hours. All other isotopes have half-lives under seven hours, and most under a minute. The shortest-lived known isotope is 217Ac with a half-life of 69 ns. Purified 227Ac comes into equilibrium with its decay products (mainly 227Th and 223Ra) after 185 days.
Many drivers have blood levels far exceeding the therapeutic dose range and often in combination with alcohol, illegal, or addictive prescription drugs, suggesting a high degree of potential for non-medical use of benzodiazepines, zolpidem, and zopiclone. Zopiclone, which at prescribed doses causes moderate impairment the next day, has been estimated to increase the risk of vehicle accidents by 50%, causing an increase of 503 excess accidents per 100,000 persons. Zaleplon or other nonimpairing sleep aids were recommended be used instead of zopiclone to reduce traffic accidents. Zopiclone, as with other hypnotic drugs, is sometimes used to carry out criminal acts such as sexual assaults. Zopiclone has crosstolerance with barbiturates and is able to suppress barbiturate withdrawal symptoms. It is frequently self-administered intravenously in studies on monkeys, suggesting a high risk of addictive potential. Zopiclone is in the top ten medications obtained using a false prescription in France.
David Kogan , has worked as journalist and senior executive at the BBC, Reuters Television, Granada Channels, Wasserman Media Group and Magnum Photos; producer working on Today; at BBC Television working on Newsnight and Breakfast Time; and at BBC America; was managing editor - global managing director at Reuters Television; was executive director at Granada Channels and was executive director/CEO of Magnum Photos from 2015 to 2019.; was Premier League's chief media rights adviser.; was awarded OBE .; director of LabourList, an independent news site for the Labour Party. He resigned as director in April 2025. Daniel Korski (born April 1977); Polish Jewish ancestry, journalist, political adviser and businessperson; worked as deputy head of Number 10 Policy Unit for David Cameron; vice-president of Jewish Leadership Council. Korski reported for Financial Times, Jewish News, then The Spectator as war correspondent in Libya. In 2008, he was described as a "Balkans expert" working at the European Council on Foreign Relations (ECFR), a think tank. In 2011, he was working as a senior policy fellow for the ECFR and running the Middle East programme there. In 2012, was appointed as strategic adviser to Catherine Ashton, then working as High Representative of the Union for Foreign Affairs and Security Policy; was made a Commander of the Order of British Empire (CBE) in 2016 as part of David Cameron's resignation honours alongside other advisers.
Chitosan is a linear polysaccharide composed of randomly distributed β-(1→4)-linked D-glucosamine (deacetylated unit) and N-acetyl-D-glucosamine (acetylated unit). It is made by treating the chitin shells of shrimp and other crustaceans with an alkaline substance, such as sodium hydroxide. Chitosan has a number of commercial and possible biomedical uses. It can be used in agriculture as a seed treatment and biopesticide, helping plants to fight off fungal infections. In winemaking, it can be used as a fining agent, also helping to prevent spoilage. In industry, it can be used in a self-healing polyurethane paint coating. In medicine, it is useful in bandages (in the form of chitosan hydrocolloid dressing) to reduce bleeding and as an antibacterial agent; it can also be used to help deliver drugs through the skin.
Sources: en.wikipedia.org
This list of notable coffeehouse chains catalogues the spread and markets share of coffeehouses world-wide. This list excludes the many companies which operate coffeeshops within retail establishments, notably bookstores and department stores, or restaurants or convenience stores which also serve coffee. These chains frequently engage in coffee wars to gain brand and consumer market share. Starbucks, Luckin Coffee and Dunkin' are the three largest coffee companies in the world, respectively. The largest coffee houses typically have substantial supply-chain relations with the world's major coffee-producing countries. They collectively wield prominent influence in global coffee economics by setting commodity prices, maintaining value chains, and supporting developing economics.
==== Evolution stability ==== The genomes of non-segmented negative-stranded RNA viruses (including paramyxoviruses) have a low rate of homologous recombination and evolve comparatively slowly. Multiple reasons for this genomic stability likely exist: (1) the genomes of these viruses are nonsegmented, therefore cannot undergo genetic reassortment, (2) each protein and each amino acid has an important function. Therefore, any new genetic insertion, substitution or deletion would lead to a decrease or total loss of function that would in turn cause the new virus variant to be less viable. (3) Sendai virus belong to viruses that are governed by the "rule of six". SeV genome as genomes of other paramyxoviruses mainly include six genes, which encode for six major proteins. Low rate of homologous RNA recombination in paramyxoviruses probably results from this unusual genomic requirement for polyhexameric length (6n+0). Natural high genomic stability of SeV is a positive feature for it potential use as a vaccine vector or as an oncolytic agent. For any clinical or industrial applications, it is important that SeV genomic and inserted foreign trans genes would be expressed in a stable way. Paramyxoviruses show relatively little genomic or antigenic change over time. They are known to stably express a wide variety of heterologous antigens at relatively high levels in many species of animals.
==== Other drugs ==== Apomorphine (Ixense; Spontane; TAK-251; Uprima) – non-selective dopamine receptor agonist, other actions – erectile dysfunction [146] Bremelanotide (Rekynda; Vyleesi; PT-141) – melanocortin MC4 receptor agonist – female sexual dysfunction [147] Dapoxetine (LY-210448; LY210448; LY-210,448; Priligy) – selective serotonin reuptake inhibitor (SSRI) – premature ejaculation [148] Flibanserin (Addyi; BIMT-17; BIMT-17-BS; Girosa) – serotonin 5-HT1A receptor agonist, serotonin 5-HT2A receptor antagonist, other actions – female sexual dysfunction [149] Lidocaine/prilocaine (Fortacin; Prilocaine Lidocaine Plethora; prilocaine/lidocaine; PSD-502; Senstend; Tempe) – combination of lidocaine (sodium channel blocker, local anesthetic) and prilocaine (sodium channel blocker, local anesthetic) – premature ejaculation [150] Moxisylyte (thymoxamine) – α1-adrenergic receptor antagonist – erectile dysfunction Papaverine (Pavabid) – phosphodiesterase PDE10A inhibitor, other actions – erectile dysfunction Phentolamine (Vasomax) – α1- and α2-adrenergic receptor antagonist – erectile dysfunction
ZMapp was first used during the 2014 West Africa Ebola Virus outbreak, having not previously undergone any human clinical trials to determine its efficacy or potential risks. By October 2014, the United States Food and Drug Administration had approved the use of several experimental drugs, including ZMapp, to be used on patients infected with Ebola virus. The use of such drugs during the epidemic was also deemed ethical by the World Health Organization (WHO). In 2014, a limited supply of ZMapp was used to treat 7 individuals infected with the Ebola virus; of these 2 died. The outcome is not considered to be statistically significant. Mapp announced in August 2014, that supplies of ZMapp had been exhausted.
Sources: en.wikipedia.org
The main change is sublimation, in which ice becomes water vapor without melting into liquid water. This occurs when the chamber pressure is held below the vapor pressure of ice while mild heat is supplied. The result is a dry, porous solid that retains much of its original shape.
Freezing determines ice crystal size, solute distribution, and the pore network left after drying. A slow or fast freezing rate can produce different cake structures and affect reconstitution. It also sets whether the formulation follows an amorphous or crystalline drying path.
It removes most free water during primary drying and part of the bound water during secondary drying. A small residual moisture content often remains and is specified for each product. Complete removal is generally neither practical nor desirable for stability.
Primary drying removes ice by sublimation under vacuum. Secondary drying removes water that is bound to the material, often by warming the product after most ice has left. Both stages occur below temperatures that would cause unwanted melting.