A practical reference on Collapse temperature: what it is, how it behaves, what the literature reports, and where the honest uncertainties sit.
Reviewed 2026-08-01. Anything still debated is marked as such rather than presented as settled.
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.
The process usually has three stages: freezing, primary drying, and secondary drying. Freezing sets the ice crystal structure and can determine pore size in the final cake. Primary drying removes free ice by sublimation at low pressure and low shelf temperature. Secondary drying removes bound water by raising the shelf temperature, although some water may remain as part of the solid. Cycle parameters depend on formulation, fill volume, vial type, and equipment performance.
Freeze-drying is distinct from simple evaporation and from spray drying. Evaporation removes water at temperatures above freezing, while spray drying rapidly dries droplets in a heated gas stream. Lyophilization avoids high temperatures, which can be useful for heat-sensitive materials such as proteins, vaccines, and some foods. The porous cake produced by sublimation dissolves or rehydrates more quickly than a dense dried mass. Not all materials tolerate freezing or the pH shifts that can occur as solutes concentrate during ice formation.
Lyophilization removes water from a frozen material by sublimation under reduced pressure. The process begins with freezing, which converts liquid water into ice and fixes the structure of the sample. After freezing, primary drying lowers pressure so ice changes directly to vapor without passing through a liquid phase. Secondary drying then removes bound water that remains after ice sublimation. The result is a dry, porous solid that often retains its original shape.
| 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. |
The physics of lyophilization depends on phase boundaries and heat and mass transfer. During primary drying, heat supplied to the product must equal the latent heat of sublimation, while water vapor moves through the drying cake to the condenser. If shelf temperature or pressure is set too high, the ice front can exceed the collapse temperature, causing meltback or pore collapse. If conditions are too cold, drying slows and costs rise. Formulation excipients, vial geometry, and freezing rate alter these limits.
Equipment for lyophilization includes a vacuum chamber, temperature-controlled shelves, a condenser, and a vacuum pump. A refrigeration system cools the shelves and condenser below the product's freezing point. Process monitoring often uses Pirani and capacitance manometers, thermocouples, and resistance sensors. Cycle development balances product quality with time and energy use. Some products are annealed during freezing to improve crystallization of bulking agents. Open questions remain about scaling cycles between laboratory, pilot, and production freeze-dryers.
Lyophilization, also called freeze-drying, removes water from a frozen material by sublimation under reduced pressure. The process begins with freezing, which converts free water into ice and may also produce a glassy phase. Primary drying then lowers chamber pressure so ice sublimes directly to vapor without passing through a liquid stage. Secondary drying raises the temperature modestly to remove bound water. The result is a porous, dry solid that usually reconstitutes quickly. Each stage influences pore structure, residual moisture, and stability.
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.
How the secretion of motilin is regulated is largely unknown, although some studies suggest that an alkaline pH in the duodenum stimulates its release. However, at low pH it inhibits gastric motor activity, whereas at high pH it has a stimulatory effect. Some studies in dogs have shown that motilin is released during fasting or interdigestive period, and intake of food during this period can prevent the secretion of motilin. Intravenous injection of glucose, which increases the release of insulin, is also found to inhibit cyclic elevation of plasma motilin. Other studies on dogs have also suggested that motilin acted as endogenous ligand in positive feedback mechanism to stimulate the release of more motilin. In dogs and cats, motilin secretion is stimulated by hydrogen ions (protons) and lipids when the animal is in a "fed" state. However, during fasting, motilin is periodically released into the serum to initiate phase III of the migrating motor complex.
{\displaystyle \delta {\ce {^{13}C}}=\left({\frac {\left({\frac {{\ce {^{13}C}}}{{\ce {^{12}C}}}}\right)_{\text{sample}}}{\left({\frac {{\ce {^{13}C}}}{{\ce {^{12}C}}}}\right)_{\text{standard}}}}-1\right)\times 1000}
== Further reading == Kim ES, Deeks ED (September 2015). "Empagliflozin/Linagliptin: A Review in Type 2 Diabetes". Drugs. 75 (13): 1547–57. doi:10.1007/s40265-015-0457-z. PMID 26323340. S2CID 27675087.
10, 2 November 2009 Marko Attila Hoare, The EU and the Georgian war: Saying 'everyone is to blame' isn't good enough, Henry Jackson Society, 25 October 2009 Ministry of Foreign Affairs of Georgia, MAIN FINDINGS OF THE “TAGLIAVINI REPORT”, 10 November 2009 (in Russian) Асмус: война в Грузии – попытка России изменить систему евробезопасности, ru.DELFI.lt, 24 January 2010 (in Russian) Blogger cyxymu: Russo-Georgian War. After three years, Echo of Moscow, 8 August 2011 (in Russian) 8 myths about the Russo-Georgian war 08.08.08, 8 August 2011 (in Russian) Andrey Illarionov, Russo-Georgian War. Who was the first? (in Russian) Pavel Felgenhauer, The first part of the war with Georgia, Zhurnalny Zal, 9 April 2012 (in Russian) "A Lost Day". All the truth about the 08.08.08 war (in Russian) "A Lost Day". Film about the war 08.08.08, Echo of Moscow, 8 August 2012 (in Russian) Andrey Illarionov, Why did Medvedev award the order of Zhukov to 10th Special Forces Brigade?, Echo of Moscow, 2 November 2013 damoukidebloba.com, RUSSIAN PEACEKEEPERS IN THE 2008 AUGUST WAR, 21 October 2015. Russian translation. (in Russian) Война 08.08.08. 8 лет спустя, Inform Napalm, 7 August 2016 Egeuene Chausovsky, Looking Back on the Russian-Georgian War, 10 Years Later, Stratfor, 7 August 2018 (in Russian) Medvedev or Putin - who decided to send troops into Georgia, Russian BBC, 7 August 2016
=== Sources of veterinarian stem cells === Veterinary applications of stem cell therapy as a means of tissue regeneration have been largely shaped by research that began with the use of adult-derived mesenchymal stem cells to treat animals with injuries or defects affecting bone, cartilage, ligaments and/or tendons. There are two main categories of stem cells used for treatments: allogeneic stem cells derived from a genetically different donor within the same species, and autologous mesenchymal stem cells, derived from the patient before use in various treatments. A third category, xenogenic stem cells, or stem cells derived from different species, are used primarily for research purposes, especially for human treatments.
Sources: en.wikipedia.org
=== The JGRB and the Representative Body for Sergeants and Inspectors === From 1927 to 1962, Garda members were represented for limited purposes by a Joint Garda Representative Body (JGRB); this body was criticised as dominated by senior officers and unable to secure needed changes in conditions of work. After a major and unauthorised meeting of hundreds of rank-and-file Gardaí at the Macushla Ballroom in Dublin, a chain of events led to the establishment by the then Minister for Justice, Charles Haughey, of three new representative bodies, divided by rank, including the Representative Body for Inspectors, Station Sergeants and Sergeants (RBISS). That body was permitted to appoint a sergeant, on secondment, as its part-time general secretary. It was also permitted to apply to the Garda Commissioner for permission to request a subscription from members. The three bodies could, and were required to if requested by the Garda Commissioner, form a temporary joint representative body. There was cooperation at other levels too, with the magazine The Garda Review being issued by the GRA and AGSI together.
8 May Skipton Building Society becomes the first building society since the 2008 financial crisis to announce it will offer 100% mortgages, aimed at first-time buyers who cannot afford a deposit. Coronation of Charles III and Camilla: Official photographs of the King and Queen taken shortly after the Coronation ceremony are released. On the final day of celebrations, people are encouraged to get involved in the Big Help Out by joining volunteer projects across the UK. 9 May House of Commons Speaker Sir Lindsay Hoyle unveils two new stained glass windows at the Palace of Westminster. One featuring his new personal coat of arms, with a rugby league ball, bees and Lancashire roses. The other window celebrates Britain's Coat of Arms of all three Crown Dependencies and all sixteen British Overseas Territories. Hoyle said at the unveiling the windows were and "will forever be tangible reminders of the strong, close links between the United Kingdom, the overseas territories and the crown dependencies". A Freedom of Information request filed by The Guardian reveals that at least one baby has been born with the DNA of three people, with 0.1% of the third person's DNA used in an attempt to prevent children developing mitochondrial diseases. Addressing the issue of arrests made during the Coronation, Sir Mark Rowley, Commissioner of the Metropolitan Police, says it is unfortunate people were not allowed to protest, but that there was a credible threat to disrupt the ceremony.
=== Types === Demyelinating diseases can be divided in those affecting the central nervous system (CNS) and those affecting the peripheral nervous system (PNS). They can also be classified by the presence or absence of inflammation. Finally, a division may be made based on the underlying cause of demyelination: the disease process can be demyelinating myelinoclastic, wherein myelin is destroyed; or dysmyelinating leukodystrophic, wherein myelin is abnormal and degenerative.
Gram Parsons died from a drug and alcohol overdose on September 19, 1973. He was 26 years old. In the late 1960s, Parsons began to vacation at Joshua Tree National Monument in southeastern California, where he used psychedelics and said he experienced UFO sightings. After splitting from Burrell, Parsons often spent his weekends there with Margaret Fisher and Phil Kaufman. Scheduled to resume touring in October 1973, Parsons decided to go on another recuperative excursion on September 17. Accompanying him were Fisher, his assistant Michael Martin, and Martin's girlfriend Dale McElroy. On both nights of their stay, Parsons retreated to the desert, consuming large amounts of alcohol and barbiturates, while the rest of the group visited bars in nearby Yucca Valley. On September 18, Martin drove back to Los Angeles to resupply the group with marijuana. That night, Parsons challenged Fisher and McElroy to drink with him; Fisher did not drink and McElroy was recovering from illness. Parsons said that he would drink for the three of them and drank six double tequilas. The three then went to the Joshua Tree Inn, where Parsons purchased morphine from an unknown woman; after being injected by her in Room No. 1, he overdosed. Fisher gave Parsons an ice cube suppository, and then a cold shower and moved him to Room No. 8. She put him to bed and went out to buy coffee in the hope of reviving him, leaving McElroy to stand guard. As his breathing became irregular and then ceased, McElroy attempted resuscitation. After all attempts failed, they called an ambulance.
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.
Lyophilization relies on sublimation, so water moves from solid ice to vapor without becoming liquid. The material is frozen, pressure is reduced, and controlled heat is supplied. Vapor is captured on a cold condenser, leaving a dry porous solid.