If you have been reading about Sublimation 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.
Last reviewed on 2025-12-04. Where a claim depends on a specific study, the study is described rather than over-claimed.
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.
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 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.
| Property | Value | Notes |
|---|---|---|
| Physical state | Solid, porous cake or powder | Depends on formulation and container |
| Typical storage temperature | 2–25 °C, protected from moisture | Some materials require colder conditions |
| Solubility class | Usually readily soluble after reconstitution | Not an intrinsic chemical property |
| Common analytical method | Karl Fischer titration | Used for residual moisture |
| Common synonyms | Freeze-drying; lyophilisation | Lyophilisation is a spelling variant |
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.
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.
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 formulation often contains excipients that protect the active ingredient during freezing and drying. Bulking agents provide structure, while lyoprotectants stabilize sensitive molecules. The freezing step can produce ice crystals whose size and distribution affect the drying rate, and cycle design includes freezing, annealing, and drying phases. If the product temperature rises above a critical value, the cake may collapse or lose its porous structure. Successful lyophilization therefore depends on the interaction between formulation, equipment, and cycle design.
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.
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.
The physics of freeze-drying couples heat transfer, mass transfer, and phase change. Heat supplied through the shelf must reach the sublimation front without melting the ice or degrading the product. Water vapor then travels through the already dried layer and leaves the chamber, where low pressure and cold traps keep it from returning. The dried layer acts as a resistance to vapor flow, so drying rate changes as the front recedes. Open questions remain about how pore structure and formulation heterogeneity affect drying uniformity at larger scales.
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.
molecular cloning Any of various molecular biology methods designed to replicate a particular molecule, usually a DNA sequence or a protein, many times inside the cells of a natural host. Commonly, a recombinant DNA fragment containing a gene of interest is ligated into a plasmid vector, which competent bacterial cells are then induced to uptake in a process known as transformation. The bacteria, carrying the recombinant plasmid, are then allowed to proliferate naturally in cell culture, so that each time the bacterial cells divide, the plasmids are replicated along with the rest of the bacterial genome. Any functioning gene of interest within the plasmid will be expressed by the bacterial cells, and thereby its gene products will also be cloned. The plasmids or gene products, which now exist in many copies, may then be extracted from the bacteria and purified. Molecular cloning is a fundamental tool of genetic engineering employed for a wide variety of purposes, often to study gene expression, to amplify a specific gene product, or to generate a selectable phenotype.
== Background and recording == Produced by Ethan Kath, III was recorded in Berlin and Warsaw, and mixed in London. The album addresses the theme of oppression, with the musicians using different pedals and keyboards to create a diverse "palette of sound". "A lot of bad things have happened to people close to me since II and it's profoundly influenced my writing as I've realized there will never be justice for them. I didn't think I could lose faith in humanity any more than I already had, but after witnessing some things, it feels like the world is a dystopia where victims don't get justice and corruption prevails", Alice Glass explained in a statement. On October 9, 2012, the track listing for the album was revealed via the duo's official Facebook page.
The yearly Ministerial Council Meeting, with the Ministers of Economy of all member countries and the candidates for enhanced engagement among the countries. The annual OECD Forum, which brings together leaders from business, government, labour, civil society and international organisations. Held every year since June 2000, the OECD Forum takes the form of conferences and discussions, is open to public participation and is held in conjunction with the MCM. Thematic Ministerial Meetings, held among ministers of a given domain (i.e., all Ministers of Labour, all Ministers of Environment, etc.). The bi-annual World Forum on Statistics, Knowledge and Policies, which does not usually take place in the OECD. This series of meetings has the ambition to measure and foster progress in societies. The Forum for Harmful Tax Practices OECD Eurasia Week, which includes several high-level policy dialogue discussions to share best practices and experiences in addressing common development and economic challenges in Eurasia.
== In plants == Approximately 30 GRX isoforms are described in the model plant Arabidopsis thaliana and 48 in Oryza sativa L. According to their redox-active centre, they are subgrouped in six classes of the CSY[C/S]-, CGFS-, CC-type and 3 groups with additional domains of unknown function. The CC-type GRXs are only found in higher plants. In Arabidopsis, GRXs are involved in flower development and Salicylic acid signalling.
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=== Mitral regurgitation === Chest x-ray in mitral regurgitation can show an enlarged left atrium, as well as pulmonary venous congestion. It may also show valvular calcifications specifically in combined mitral regurgitation and stenosis due to rheumatic heart disease. ECG typically shows left atrial enlargement, but can also show right atrial enlargement if the disease is severe enough to cause pulmonary hypertension. Echocardiography is useful in visualizing the regurgitant flow and calculating the RF. It can also be used to determine the degree of calcification, and the function and closure of the valve leaflets. Severe disease has an RF of >50%, while progressive mitral regurgitation has an RF of <50%.
The Royal Arch Purple, properly the Grand Royal Arch Purple Chapter of Ireland, is an organisation related to Orangeism but not recognised by the Grand Orange Lodge of Ireland which recognises only two degrees, those of Orange and Plain Purple. It is a necessary prerequisite for entry into the Royal Black Institution.
=== Beverages === Buckwheat tea, known as kuqiao-cha (苦荞茶) in China, memil-cha (메밀차) in Korea and soba-cha (蕎麦茶) in Japan, is a tea made from roasted buckwheat. Buckwheat has been used as a substitute for other grains in gluten-free beer. It is used in the same way as barley to produce a malt that can form the basis of a mash that will brew a beer without gliadin or hordein (together gluten) and therefore can be suitable for coeliacs or others sensitive to certain glycoproteins. Buckwheat whisky is a distilled alcoholic beverage made from buckwheat. It is produced in the Brittany region of France and in the United States. Buckwheat shōchū (焼酎) is a Japanese distilled beverage produced since the 16th century. The taste is milder than barley shōchū.
MLSE and NBA had applied to register the Raptor's logo Raptors, a basketball with three diagonal claw gashes, for various goods and services. The Trademark Trial and Appeal Board dismissed Monster's claim. In March 2016, Monster filed a lawsuit to revoke the company trademark of Thunder Beast LLC of Washington, D.C., a small root beer brewery, insisting the use of "beast" in the company name encroached on Monster's trademark slogan, "Unleash the Beast". The owner of Thunder Beast, Stephen Norberg, was fighting Monster's lawsuit as of 2019. In August 2018, Monsta Pizza of Wendover in Buckinghamshire, United Kingdom, fought a claim brought by Monster Energy in the Intellectual Property Office. The claim was that the pizza firm could be mistaken for Monster Energy, leaving customers confused. The pizza firm won a landmark ruling against Monster Energy, when the court decided there would be no case of misrepresentation. In fact, Monster Energy loses many of their lawsuits; however, as with other cases of "trademark bullying", the main goal of the lawsuit seems to be bankrupting the opposition at which they are quite successful. Also in 2018, Monster Energy brought a lawsuit against Vital Pharmaceuticals Inc. (VPX), then producer of Bang Energy, a competitor of Monster Energy. The lawsuit alleged false advertising as well as theft of trade secrets. The matter concluded with a jury verdict in favor of Monster Energy.
== Personal life == On November 11, 1932, he married the socially connected Blanchette Ferry Hooker (1909–1992), who was to serve as chairman of the Asian Cultural Council from 1980 to 1990, and who established the Blanchette H. Rockefeller Fellowship Fund, in Japan. They had one son and three daughters:
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=== Encoding === Methionine is one of only two amino acids encoded by a single codon (AUG) in the standard genetic code (tryptophan, encoded by UGG, is the other). In reflection to the evolutionary origin of its codon, the other AUN codons encode isoleucine, which is also a hydrophobic amino acid. In the mitochondrial genome of several organisms, including metazoa and yeast, the codon AUA also encodes for methionine. In the standard genetic code AUA codes for isoleucine and the respective tRNA (ileX in Escherichia coli) uses the unusual base lysidine (bacteria) or agmatidine (archaea) to discriminate against AUG. The methionine codon AUG is also the most common start codon. A "Start" codon is message for a ribosome that signals the initiation of protein translation from mRNA when the AUG codon is in a Kozak consensus sequence. As a consequence, methionine is often incorporated into the N-terminal position of proteins in eukaryotes and archaea during translation, although it can be removed by post-translational modification. In bacteria, the derivative N-formylmethionine is used as the initial amino acid.
==== Efp ==== Efp, or estrogen-inducible RING-finger protein, is an E3 ubiquitin ligase whose overexpression has been shown to be the major cause of estrogen-independent breast cancer. Efp's substrate is 14-3-3 protein which negatively regulates cell cycle.
=== Active site === There are two distinct bi-lobed active site cavities located at the bottom edge of each monomer’s αβαβα core. Identical six-residue loops, which meet at the dimer interface, separate the two active sites from each other. The loops being with Thr132 in the active site and ends with a cis-peptide bond to Pro138. A Met137 residue plugs a hole in the other monomer’s active site. Therefore, the active site is buried except for a 16 Å CoA-binding tunnel that connects the catalytic surface to the outer surrounding milieu. The width of the tunnel is too narrow for the aromatic substrates and products that must pass through it, implying that there must be some dynamic mobility within and around the tunnel when placed in solution. The active site contains a conserved catalytic triad of Cys164, His303 and Asn336. These residues aid in multiple decarboxylation and condensation reactions, with Cys164 acting as the active site nucleophile. Phe215 and Phe265 are two other important amino acids that act as “gatekeepers” to block the lower protein of the opening between the CoA-binding tunnel and the active site cavity. This limits the access of water to the active site while accommodating substrates and intermediates of varying shapes and sizes. Phe215 also orients the substrates at the active site during elongation of the polyketide intermediate.
Bassinger reprised the role of Stargirl in the ninth episode of the fourth season of the HBO Max series Titans, titled "Dude, Where's My Gar?"; that series exists on Earth-9 of the live action multiverse.
Sources: en.wikipedia.org
Freezing only converts liquid to solid. Lyophilization adds vacuum and controlled warming so frozen solvent sublimes, leaving a dry porous solid. The two steps are related but not interchangeable.
Reduced pressure keeps the solvent below its triple point, allowing ice to become vapor without melting. Vacuum also helps remove water vapor from the product chamber. The exact pressure is chosen with the formulation and equipment.
Residual moisture is water that remains in the dried solid after secondary drying. It is often measured by Karl Fischer titration, near-infrared spectroscopy, or thermogravimetry. Acceptable levels depend on the material and its stability profile.
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.