Everything below concerns Lyophilization. We keep the language plain, cite what the science says, and separate well-supported claims from open questions.
Last reviewed on 2025-11-30. Where a claim depends on a specific study, the study is described rather than over-claimed.
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.
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.
| Property | Value | Notes |
|---|---|---|
| Common name | Freeze-drying | Process removes water by sublimation under vacuum. |
| Typical primary drying shelf temperature | -40 C to -10 C | Set below the formulation's collapse temperature. |
| Typical chamber pressure | 0.05-0.3 mbar | Low pressure allows ice to sublime below its triple point. |
| Water content after drying | 0.5-3% by weight | Higher values may reduce storage stability for some materials. |
| Key thermal parameter | Collapse temperature | Measured by freeze-drying microscopy or differential scanning calorimetry. |
Lyophilization is a dehydration process that removes water from a frozen material by sublimation under low pressure. The material is first frozen to convert liquid water into ice. Next, the pressure is reduced below the triple point of water so that ice changes directly into vapor without passing through a liquid phase. This step is called primary drying. The result is a porous solid or cake that retains the original shape of the frozen solution.
After primary drying, secondary drying removes water that remains bound to the material. This stage raises the shelf temperature while maintaining low pressure, which encourages desorption of unfrozen water. Residual moisture can be reduced to a low percentage, improving stability for many products. The process parameters, including freezing rate, shelf temperature, and chamber pressure, influence the final pore structure and reconstitution behavior. Control of these variables helps prevent collapse or meltback during drying.
A typical cycle begins with freezing, which fixes the material into a solid and determines ice crystal size. Primary drying then raises heat under vacuum so ice sublimes, often near or below the collapse temperature of the formulation. Secondary drying removes bound water that remains after ice is gone, usually by gently warming the product. Each stage balances heat input against pressure to avoid melting or structural damage. Temperature probes and pressure sensors guide the transition between stages.
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.
==== History ==== Kelp tea is thought to have been drunk from quite a long time ago because "the Japanese have incorporated kelp and seaweed into their diets for 1,500 years". It is said that, in 951, Kūya made a statue of the Ekādaśamukha to cure an epidemic that was spreading in the capital and went around the city giving oo-buku-cha to the sick. Tea using kelp already existed in Edo period (1603–1868) at the latest, and people in these days drank it by pouring boiling water over chopped kelp.
The inquiry will have two areas of focus – a review of the "placement and categorisation" of all inmates at Wandsworth, and an investigation of all people in custody currently charged with terror offences. The UK's first EV-only manufacturing plant begins production at Ellesmere Port, Cheshire. The UK experiences a fourth day of temperatures exceeding 30 °C (86 °F), the highest consecutive number on record for the month of September, with hot weather expected to continue until the weekend. 8 September – The first anniversary of the death of Elizabeth II is marked by gun salutes at Hyde Park and the Tower of London, as well as the release of a short message from Charles III along with a previously unreleased portrait of the Queen taken in 1968. 9 September – Following a four-day manhunt, Daniel Khalife is arrested by the Metropolitan Police in Chiswick, London. 10 September The Sunday Times reports that two men have been arrested under the Official Secrets Act, including a researcher in the UK Parliament accused of spying for China. Mo Farah, considered one of the greatest British athletes of all time, takes part in the final race of his career at age 40, finishing fourth in the Great North Run. The Metropolitan Police confirm that Daniel Khalife has been charged with escaping from Wandsworth Prison. He appears before Westminster Magistrates Court the following day, where he is remanded in custody until 29 September. 11 September The GMB Union confirms that the UK's 400 Wilko stores will close by early October after a bid to rescue the retailer fell through.
Proteomics is the large-scale study of proteins. The proteome is the entire set of proteins produced or modified by an organism or system. Proteomics is an interdisciplinary field that covers the exploration of proteomes from the overall level of protein composition, structure, and activity. While the scale and complexity of the proteome is formidable, recent technological progress has substantially expanded the sensitivity and scope of proteome analysis. Proteomics generally denotes the large-scale experimental analysis of proteins and proteomes, but often refers specifically to protein purification and mass spectrometry. Indeed, mass spectrometry is the most powerful method for analysis of proteomes, both in large samples composed of millions of cells, and in single cells. Proteins are vital macromolecules of all living organisms, with many functions such as the formation of structural fibers of muscle tissue, enzymatic digestion of food, or synthesis and replication of DNA. In addition, other kinds of proteins include antibodies that protect an organism from infection, and hormones that send important signals throughout the body. Proteomics enables the identification of ever-increasing numbers of proteins. This varies with time and distinct requirements, or stresses, that a cell or organism undergoes.
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Xaa-Pro dipeptidase, also known as prolidase, is an enzyme that in humans is encoded by the PEPD gene. Prolidase is an enzyme in humans that plays a crucial role in protein metabolism and collagen recycling through the catalysis of the rate-limiting step in these chemical reactions. This enzyme is coded by the gene PEPD (peptidase D), located on chromosome 19. Serum prolidase activity is also currently being explored as a biomarker for diseases.
Andros Darryl Townsend (born 16 July 1991) is an English professional footballer who plays as a right winger for Thai League 1 club PT Prachuap. A graduate of the Tottenham Hotspur academy, Townsend was initially loaned out to several League One and then Championship clubs alongside limited Tottenham first-team appearances, before making his Premier League debut in September 2012. After further limited appearances and then a half-season loan to Premier League club Queens Park Rangers, Townsend established himself as a Tottenham player between 2013 and 2015. He subsequently fell out of favour at Tottenham, and following a short spell at Newcastle United in the 2015–16 season, he transferred to fellow English side Crystal Palace in the summer of 2016. After five years at Palace, he departed for Everton in 2021, though his time at the club was hampered by a long-term injury sustained in 2022. Upon his release from Everton, in July 2023, he joined Luton Town. Townsend earned his first England cap on 11 October 2013, and made 13 appearances in his senior international career, scoring three goals.
24195Am + 42He → 24397Bk + 2 10n After the irradiation, the coating was dissolved with nitric acid and then precipitated as the hydroxide using concentrated aqueous ammonia solution. The product was centrifugated and re-dissolved in nitric acid. To separate berkelium from the unreacted americium, this solution was added to a mixture of aqueous ammonia and ammonium sulfate and heated in the presence of atmospheric oxygen to convert all the dissolved americium into the oxidation state +6. Unoxidized residual americium was precipitated by the addition of hydrofluoric acid as americium(III) fluoride (AmF3). This step yielded a mixture of the accompanying product curium and the expected element 97 in form of trifluorides. The mixture was converted to the corresponding hydroxides by treating it with potassium hydroxide, and after centrifugation, was dissolved in perchloric acid.
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To facilitate the work of the CDC, a Medical Laboratory Services Advisory Committee was appointed. Inhorn was the only State Laboratory Director to serve on the MLSAC Advisory Committee, perhaps because the WSLH had a strong history of proficiency testing in clinical laboratories in Wisconsin. Inhorn's assignment for CLIA-67 was to develop a protocol for PT programs to be used in the future. Many changes had been made to CLIA-67, but major weaknesses in the program still existed. It would take another two decades before new federal legislation, called CLIA-88, would address these shortcomings. Inhorn was appointed to the new CLIA-88 advisory board and served during the first two years of its existence. During the ensuing years, many more health laboratories opened in the U.S. and new technology introduced built-in controls, so that performance was validated without confirmation by laboratory workers.
== A scientific home in Pittsburgh == In a few short years, the Dean of the School of Medicine, himself a professor of Biochemistry, invited Hofmann to become Chairman of the Department. From the moment he took the position of Chairman of Biochemistry, it became clear that although he would always be a son of Switzerland, the United States offered him career opportunities he could never hope for in a small country like Switzerland. The US was to become his permanent home. The burgeoning field of peptide chemistry became his scientific focus and, in his own words, he fell in love with a molecule that was known to stimulate the adrenal cortex to produce the very steroids that had so fascinated him in Reichstein's laboratory. That molecule, not yet isolated, was ACTH and the love affair was lifelong. Despite detours into other areas, he kept returning to ACTH. In the last years before his death, he was developing methods to isolate the ACTH receptor.
In human anatomy, the vitreous body (from Latin vitreus 'glassy') is the clear gel that fills the space between the lens and the retina of the eye (the vitreous chamber) in humans and other vertebrates. It is often referred to as the vitreous humor (also spelled humour, from Latin meaning 'liquid'), or simply "the vitreous". Vitreous fluid or "liquid vitreous" is the liquid component of the vitreous gel, found after a vitreous detachment. It is not to be confused with the aqueous humor, the other fluid in the eye that is found between the cornea and lens.
By 1809, in his Philosophie Zoologique, Lamarck had created nine phyla apart from vertebrates (where he still had four phyla: mammals, birds, reptiles, and fish) and molluscs, namely cirripedes, annelids, crustaceans, arachnids, insects, worms, radiates, polyps, and infusorians. In his 1817 Le Règne Animal, Georges Cuvier used comparative anatomy to group the animals into four embranchements ('branches' with different body plans, roughly corresponding to phyla), namely vertebrates, molluscs, articulated animals (arthropods and annelids), and zoophytes (radiata) (echinoderms, cnidaria and other forms). This division into four was followed by the embryologist Karl Ernst von Baer in 1828, the zoologist Louis Agassiz in 1857, and the comparative anatomist Richard Owen in 1860. In 1874, Ernst Haeckel divided the animal kingdom into two subkingdoms: Metazoa (multicellular animals, with five phyla: coelenterates, echinoderms, articulates, molluscs, and vertebrates) and Protozoa (single-celled animals), including a sixth animal phylum, sponges. The protozoa were later moved to the former kingdom Protista, leaving only the Metazoa as a synonym of Animalia.
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Primary drying removes ice by sublimation at low pressure and low shelf temperature. Secondary drying removes bound water by raising the shelf temperature, often under the same vacuum. The two stages differ in the water state being removed.
Freezing determines ice crystal size, pore structure, and the concentration of solutes in remaining liquid. Faster freezing generally creates smaller ice crystals and a denser dried matrix. These features affect drying rate and reconstitution behavior.
Lyophilization reduces water content but usually leaves a small amount of water in the dried material. Some water remains bound to solids or trapped in the dried matrix. Very low water targets can require extended secondary drying, which may alter product stability.
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.