Sublimation is one of those subjects where the details matter more than the headlines. This page pulls together the background, the mechanisms, and the practical points readers ask about most.
Updated 2026-02-18. Numbers and descriptions here follow the published literature rather than marketing material.
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.
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.
Freezing is the first stage and sets the ice structure that later becomes the pore network. The formulation is cooled below its freezing point, often with a controlled ramp, and solutes concentrate as ice forms. Primary drying then lowers chamber pressure and supplies heat to sublime the ice. The product temperature must stay below its collapse or eutectic temperature to prevent structural loss. Secondary drying raises the temperature modestly to remove bound water and achieve a low residual moisture.
A freeze-dryer consists of a vacuum chamber, temperature-controlled shelves, a condenser, and a vacuum pump. Vials, ampoules, or bulk trays hold the product during the cycle. The condenser traps water vapor as ice at a temperature lower than the product. Cycle development balances shelf temperature, chamber pressure, and time. Scale-up can be difficult because heat and mass transfer change with equipment size, so process analytical tools and conservative validation are often used.
Lyophilization is a dehydration technique in which a product is frozen and the solvent is removed under reduced pressure. The low pressure allows ice to sublimate directly into vapor without passing through a bulk liquid phase. This differs from conventional drying, where heat drives evaporation and can damage heat-sensitive structures. The process is used for biological materials, pharmaceutical formulations, and some foods. Its main advantage is preservation of porous structure and rapid reconstitution.
| Property | Value | Notes |
|---|---|---|
| Common synonyms | Freeze-drying; lyophilisation; cryodesiccation | Regional spelling and historical terms. |
| Primary drying pressure | 0.05-0.5 mbar (5-50 Pa) | Kept below the triple point of water; product-specific. |
| Shelf temperature range | -40 to +40 °C | Freezing, primary, and secondary stages use different set points. |
| Cycle duration | 12-72 hours | Depends on fill volume, formulation, and equipment. |
| Condenser temperature | -50 to -80 °C | Must remain below the product's ice temperature. |
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.
The low pressure used during drying allows water vapor to move from the ice surface to a cold condenser. Energy supplied as heat drives sublimation but must stay below the collapse temperature of the frozen matrix. If the product becomes too warm, the frozen structure may soften or melt, reducing pore formation and slowing drying. Formulations often include bulking agents, stabilizers, or buffers to support a rigid cake. The final moisture content depends on formulation, freezing rate, and the length of secondary drying.
Secondary drying removes bound water that remains after ice sublimation. Shelf temperature is raised gradually while pressure remains low, reducing water content to a target range. Over-drying can cause brittleness or electrostatic issues, while under-drying affects stability. The endpoint is often judged by pressure rise tests, temperature measurements, or water content analysis. Scale-up depends on matching heat and mass transfer across equipment sizes. Small changes in shelf temperature or pressure can alter cycle length substantially.
Lyophilization, or freeze-drying, removes water from a material by freezing it and then lowering pressure so ice changes directly to vapor. The process relies on sublimation, the phase transition from solid to gas without an intervening liquid state. It is used for heat-sensitive materials that would degrade in conventional drying. The three stages are freezing, primary drying, and secondary drying, each with distinct temperature and pressure requirements. In practice, cycle design balances these variables.
Although lemborexant has a longer terminal elimination half-life than suvorexant, it appears to be more rapidly cleared than suvorexant in the earlier phases of elimination. In addition, lemborexant dissociates from the orexin receptors more rapidly than does suvorexant. These differences may allow for comparatively reduced next-day effects such as daytime somnolence with lemborexant.
Another meta analysis of 4 trials with follow-up longer than 1 year found similar results. Nissen's meta analysis was criticized in a 2007 article by George Diamond et al. in the Annals of Internal Medicine. The authors concluded that Nissens' analysis had excluded trials with important data on the cardiovascular profile of rosiglitazone, had inappropriately combined trials of greatly differing design, and had inappropriately excluded trials with no cardiovascular events. The authors concluded that no firm conclusion could be drawn regarding whether rosiglitazone increased or decreased cardiovascular risk. Investigators from the Cochrane Collaboration published a meta-analysis of their own on the use of rosiglitazone in Type II diabetes, concluding there was not sufficient evidence to show any health benefit for rosiglitazone. Noting the recent publication by Nissen, they repeated their meta analysis including only the trials included in the Nissen study that dealt with Type II diabetics. (The Nissen study included some trials in people with other disorders.) They did not find a statistically significant increase in cardiovascular events, but noted that all of the cardiovascular endpoints they analyzed showed a non-significant trend toward worse outcomes in the rosiglitazone arms. In July 2007 the FDA held a joint meeting of the Endocrinologic and Metabolic Drugs Advisory Committee and the Drug Safety and Risk Management Advisory Committee. FDA scientist Joy Mele presented a meta analysis examining the cardiovascular risk of rosiglitazone in completed clinical trials.
== Annelids == Capitella teleta, polychaete (2007, 2013) Helobdella robusta, leech (2007, 2013) Eisenia fetida, earthworm (2015, 2016) Paraescarpia echinospica, deep-sea tubeworm (2021,) Hirudinaria manillensis, Asian Buffalo leech (2023) Hirudo nipponia, Japanese blood-sucking leech (2023) Whitmania pigra, Asian freshwater leech (2023)
== History == Frederick William Hope coined the term myiasis in 1840 to refer to diseases resulting from dipterous larvae as opposed to those caused by other insect larvae (the term for this was scholechiasis). Hope described several cases of myiasis from Jamaica caused by unknown larvae, one of which resulted in death. Even though the term myiasis was first used in 1840, such conditions have been known since ancient times. Ambroise Paré, the chief surgeon to King Charles IX and King Henry III, observed that maggots often infested open wounds.
Sources: en.wikipedia.org
=== Elsewhere === Generally, the firmer styles of tofu are used for kebabs, mock meats, and dishes requiring a consistency that holds together, while the softer styles can be used for desserts, soups, shakes, and sauces. Some people enjoy tofu made and prepared with chocolate and making it into pies and mousse along with other tofu desserts. This came about due to vegans and vegetarians avoiding the usage of items such as milk and eggs. Firm Western tofu types can be barbecued since they hold together on a barbecue grill. These types are usually marinated overnight as the marinade does not easily penetrate the entire block of tofu. (Techniques to increase the penetration of marinades include stabbing repeatedly with a fork or pressing out the initial water content either by hand or with a tofu press prior to marinating. Before pressing the tofu, it is sometimes frozen and thawed in order of creating a more porous texture, often compared to a sponge. This texture does not only help release the initial water content, but also allows for an altered mouthfeel and more absorbent structure. Typically, the tofu is frozen and thawed once, although some culinary experts recommend executing this technique twice for a stronger effect.) Grated firm Western tofu is sometimes used in conjunction with textured vegetable protein (TVP) as a meat substitute. Softer tofus are sometimes used as a dairy-free or low-calorie filler. Silken tofu may be used to replace cheese in certain dishes, such as lasagna.
=== Career statistics === In a nine-season career, Mizell had a 90–88 record with a 3.85 ERA in 268 games, 230 of which were starts. He pitched 61 complete games, including 15 shutouts. Mizell allowed 654 earned runs and struck out 918, walking 680 in 1,528+2⁄3 innings pitched. He enjoyed his greatest success against the Pirates, against whom he went 14–7. Mizell also won 14 of his first 17 decisions against the Cubs, but Chicago did better against him later in his career, winning 12 of their final 16 decisions against him. Writing in 1971, Ray Owen, sports editor for The Southeast Missourian, called Mizell "one of the best strikeout hurlers around the National League scene for a span of ten years."
start codon The first codon translated by a ribosome from a mature messenger RNA transcript, used as a signal to initiate peptide synthesis. In the standard genetic code, the start codon always codes for the same amino acid, methionine, in eukaryotes and for a modified methionine in prokaryotes. The most common start codon is the triplet AUG. Contrast stop codon.
== Diagnosis == When the cause of hypoglycemia is not obvious, the most valuable diagnostic information is obtained from a blood sample (a "critical specimen") drawn during the hypoglycemia. Detectable amounts of insulin are abnormal and indicate that hyperinsulinism is likely to be the cause. Other aspects of the person's metabolic state, especially low levels of free fatty acids, beta-hydroxybutyrate and ketones, and either high or low levels of C-peptide and proinsulin can provide confirmation. Clinical features and circumstances can provide other indirect evidence of hyperinsulinism. For instance, babies with neonatal hyperinsulinism are often large for gestational age and may have other features such as enlarged heart and liver. Knowing that someone takes insulin or oral hypoglycemic agents for diabetes obviously makes insulin excess the presumptive cause of any hypoglycemia. Most sulfonylureas and aspirin can be detected on a blood or urine drug screen tests, but insulin cannot. Endogenous and exogenous insulin can be distinguished by the presence or absence of C-peptide, a by-product of endogenous insulin secretion which is not present in pharmaceutical insulin. Some of the newer analog insulins are not measured by the usual insulin level assays.
In centuries past, various kinds of chorea were at times called by names such as Saint Vitus' dance, with little or no understanding of their cause or type in each case. The first definite mention of HD was in a letter by Charles Oscar Waters (1816–1892), published in the first edition of Robley Dunglison's Practice of Medicine in 1842. Waters described "a form of chorea, vulgarly called magrums", including accurate descriptions of the chorea, its progression, and the strong heredity of the disease. In 1846 Charles Rollin Gorman (1817–1879) observed how higher prevalence seemed to occur in localized regions. Independently of Gorman and Waters, both students of Dunglison at Jefferson Medical College in Philadelphia, Johan Christian Lund (1830–1906) also produced an early description in 1860. He specifically noted that in Setesdalen, a secluded mountain valley in Norway, the high prevalence of dementia was associated with a pattern of jerking movement disorders that ran in families. The first thorough description of the disease was by George Huntington in 1872. Examining the combined medical history of several generations of a family exhibiting similar symptoms, he realized their conditions must be linked; he presented his detailed and accurate definition of the disease as his first paper. Huntington described the exact pattern of inheritance of autosomal dominant disease years before the rediscovery by scientists of Mendelian inheritance.
Sources: en.wikipedia.org
=== 2000–2011: Established actor and diversification === In 2000, Carrey reteamed with the Farrelly brothers, who had previously directed him in Dumb and Dumber, for the black comedy film Me, Myself & Irene, a film that received mixed reviews but enjoyed box office success. Carrey played the role of state trooper Charlie Baileygates, who has multiple personalities and romances a woman portrayed by Renée Zellweger. That same year, Carrey starred in the second highest-grossing Christmas film of all time, How the Grinch Stole Christmas, playing the title character, for which he received both praise and criticism from critics alongside a Golden Globe nomination. For his next feature film, Carrey starred opposite Jennifer Aniston and Morgan Freeman in Tom Shadyac's international hit comedy Bruce Almighty (2003). Carrey played a television newsman who unexpectedly receives God's omnipotent abilities when the deity decides to take a vacation. The film received mixed reviews upon release but still became a financial success, earning over $484 million worldwide, and going on to become the seventeenth highest-grossing live action comedy of all time. In 2004, Carrey starred in Eternal Sunshine of the Spotless Mind. The film received critical acclaim upon release. Critics highly praised Carrey's portrayal of Joel Barish, in addition to the performance of his co-star Kate Winslet, who was nominated for an Oscar.
=== Human use === Nitrofurazone was previously available as a prescription in the U.S., and was indicated as a topical solution, topical cream, or topical ointment for the treatment of bacterial skin infections, wounds, burns, and ulcers. It was also used as a prophylactic measure to prevent infection that could potentially result in skin graft rejection. Nitrofurazone is still very popular as a topical solution for the treatment of tonsillitis in Russia.
Day of Defeat received "generally favorable reviews" according to the review aggregation website Metacritic. IGN praised the game for its use of narrow spaces to stimulate the game's "relentless pacing", and GameSpy spoke highly of its attention to detail. Reviewers also praised Day of Defeat for its promotion of teamwork through purposefully tight corridors that force players to cooperate, lest they be killed by an enemy outside their field of vision. Both GameSpy and GameSpot levied criticism against the game for its sub-par visuals and "downright ugly" color palette, blaming the aging GoldSrc engine for the aesthetic issues. Many reviewers drew parallels between Day of Defeat and Battlefield 1942, the latter of which had been released only six months prior to the former. Both games were set in World War II and featured gameplay that was heavily reliant on their respective class-based systems, which lead reviewers to make direct comparisons between the two in their reviews of Day of Defeat. The game was also faulted for its lack of usable vehicles, contrasting Battlefield's usage of operable vehicles as a key gameplay component. PC Gamer US awarded Day of Defeat its 2001 "Mod of the Year" prize. The editors wrote, "Made by amateur developers not yet of American drinking age, Day of Defeat absorbed entire weeks of office LAN play."
==== Rise of organic chemistry and experimental physiology ==== In chemistry, one central issue was the distinction between organic and inorganic substances, especially in the context of organic transformations such as fermentation and putrefaction. Since Aristotle these had been considered essentially biological (vital) processes. However, Friedrich Wöhler, Justus Liebig and other pioneers of the rising field of organic chemistry—building on the work of Lavoisier—showed that the organic world could often be analyzed by physical and chemical methods. In 1828 Wöhler showed that the organic substance urea could be created by chemical means that do not involve life, providing a powerful challenge to vitalism. Cell extracts ("ferments") that could effect chemical transformations were discovered, beginning with diastase in 1833. By the end of the 19th century the concept of enzymes was well established, though equations of chemical kinetics would not be applied to enzymatic reactions until the early 20th century. Physiologists such as Claude Bernard explored (through vivisection and other experimental methods) the chemical and physical functions of living bodies to an unprecedented degree, laying the groundwork for endocrinology (a field that developed quickly after the discovery of the first hormone, secretin, in 1902), biomechanics, and the study of nutrition and digestion. The importance and diversity of experimental physiology methods, within both medicine and biology, grew dramatically over the second half of the 19th century.
List of British Jewish writers includes writers (novelists, poets, playwrights, journalists, authors of scholarly texts and others) from the United Kingdom and its predecessor states who are or were Jewish or of Jewish descent.
Sources: en.wikipedia.org
Simple drying usually removes water by evaporation from a liquid or solid, often with heat. Lyophilization first freezes the material and then removes ice by sublimation under vacuum. This avoids prolonged exposure to liquid water and high temperatures.
Reduced pressure lowers the boiling point of water and allows ice to sublime at temperatures below freezing. It also helps remove water vapor from the product toward the condenser. The exact pressure is chosen to stay below the triple point of water.
No. Materials with low solids content or high volatile solvents may form weak or collapsed cakes. Some proteins and cells require stabilizers to survive freezing and drying stresses. Feasibility depends on formulation and process design.
Yes, the terms are generally interchangeable. Lyophilization is more common in pharmaceutical and laboratory contexts, while freeze-drying appears widely in food science and general writing. Both describe removal of solvent by sublimation under vacuum after freezing.